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Symptoms resulting from the feeding of true bugs on growing hazelnuts
Abstract
Palomena prasina (L.) (Hemiptera: Pentatomidae) and Gonocerus acuteangulatus (Goeze) (Hemiptera: Coreidae) are new pests in French hazel orchards (Corylus avellana L., Corylaceae). Knowing the symptoms in growing hazelnuts resulting from pests feeding on them is important for risk assessment and risk management. Insects were isolated in net sleeves on hazelnuts of the Pauetet cultivar at various phenological stages for 1 week, and symptoms resulting from the insects’ feeding were observed at harvest. From pre-shell expansion to kernel expansion and from kernel expansion to kernel maturation, feeding mainly results in blank nuts and necrotic spots, respectively. The feeding of adult insects, as well as third- and fourth-instars, resulted in blank nuts. When adults and fifth-instars fed on the kernel, necrotic spots resulted. The stylet penetration potential of adult insects and late-instars is higher, allowing them to reach the kernel and cause abortion or necrotic spotting. Blank nuts are the main damage observed, and their intensity is highly related to changes in both hazelnut and bug phenology. Therefore, symptoms should be discussed in light of the cultivar and bug occurrence in the field. This study contributes to the development of decision tools for integrated pest management of true bug pests that feed on hazelnuts.
... The damage produced by H. halys on hazelnuts mainly concerns the fruits. In fact, it causes different kinds of injuries depending on the development phase of the fruit [23,24]. When the bite occurs during the shell expansion, the seed growth stops, inducing a kernel abortion (empty shells). ...
... The sex ratio in the first part of the season after overwintering was biased toward females ( Figure 3b). This is another variable to consider because females are more voracious than males in several Pentatomid species, for which a greater presence of females in a period could cause higher damage [24,52]. The sex ratio varied considerably over time according to the development of the different generations (two per year), tending toward parity when the adults of the first generation of the year arrived or developed in the groves. ...
... However, the analysis of the phenological phases permits us to state that during the time of maximum density of H. halys, the early cultivar (SG) was in the kernel expansion stages. These are the most susceptible stages of fruit development for cimiciato defect occurrence, consistent with previous studies on G. acuteangulatus, P. prasina [24], and H. halys [23]. These studies indicated that the type of damage to the hazelnut kernel is strongly related to the moment of attack by stink bugs in relation to fruit development. ...
Over the past decade, Halyomorpha halys has become one of the main threats to hazelnut production. Its trophic activity makes kernels inedible due to strongly detrimental effects on the organoleptic quality. Its management in Italy is still tricky due to the lack of effective native biocontrol agents and authorized and effective insecticides. A field test was performed on San Giovanni (SG) and Tonda Romana (TR) cultivars (early and late ripening, respectively) to assess the intensity of cimiciato damage with different pest management approaches (no insecticide and integrated pest management, IPM). Moreover, phenological analysis of fruits and the monitoring of stink bug species by traps and plant beating were carried out. In the untreated plots, the SG cv showed a higher cimiciato incidence with respect to the late TR cv (40% SG-NI vs. 23% TR-NI). This was probably due to the different phenological phases in which stink bugs injured the fruits. In fact, stink bug bites provoke different kinds of injuries (blanks, shriveled, and cimiciato) according to the fruit's development period. Indeed, in the period of highest insect occurrence in the field, the fruits of the early cv (SG) were in kernel expansion, a phenological phase in which bug injuries are more likely in cimiciato defects. Lastly, the IPM did not provide sufficient fruit protection (19% SG-IPM vs. 11% TR-IPM). The interaction between the phenological development of hazelnuts and the brown marmorated stink bug represents a critical aspect in understanding and implementing effective strategies for controlling this key pest on hazelnut trees.
... Few species had been identified as major pests [9][10][11], but when orchards are not treated with regularly with pesticides, these species can cause significant yield losses. In France, the hazelnut weevil, Curculio nucum Linnaeus, 1758 (Coleoptera: Curculionidae: Curculionini), is the main pest, followed by generalist pests, such as true bugs [12]. ...
... The net sleeves were then opened to remove the weevils and treated to avoid missing any, as described by Hamidi and coll. [12]. The experiment ended on 2 August. ...
... The relationship between belted nuts, blank nuts, and shrivelled kernels and kernel development stage was the same observed with true bugs [12,36,37]; that is, when the kernels were less than~5 mm in diameter, the seeds died, leading from belted to blank nuts. When the shells stopped growing, blank nut symptoms were prevalent. ...
Hazelnut is an important food resource for the larvae and adults of the hazelnut weevil, Curculio nucum. While wormy nuts reflect the impact of such weevils at harvest time, little is known about the other types of damage they cause. To establish a comprehensive list of damages, and thereby identify the period of hazelnut vulnerability, male and female weevils were collected weekly and isolated on fruiting branches for 1 week. Based on nut development, higher rates of dropped nutlets, belted nuts, and blank nuts were observed at harvest. Marks specific to weevils, including wormy nuts, riddled shells, and larvae paths on the basal scar, were recorded during nut lignification. Belted nuts and blank nuts are empty nuts and constituted the main damage. The feeding activities of both the adults and larvae, but also the oviposition punctures, are likely to be the main causes of embryo abortions. The greatest damages occurred during kernel growth and when the shell had almost reached its final size. The larvae failed to penetrate fully lignified shells, with dead larvae mainly being found on the basal scar, the later softer part of the hazelnut. In Ségorbe cultivars, the dynamic of hazelnut development is the main factor involved in its susceptibility to C. nucum, with aborted nuts being the most underestimated damage.
... Palomena prasina (L.) (Hemiptera: Pentatomidae), the green shield bug (GSB), is a widely distributed species in the Eurosiberian region (Lupoli & Dusoulier, 2015). The feeding punctures of this polyphagous stink bug lead to kernel necrosis or to empty hazelnuts (Romero et al., 2009) with type of damage depending on the feeding period (Hamidi et al., 2022). As a consequence, P. prasina causes heavy crop losses in commercial orchards in Europe (e.g. ...
... Saruhan et al., 2023;Ateş &Kaçar, 2021, for Turkey, andBosco et al., 2018, for Italy). In southern France, P. prasina is a major pest of hazelnuts (Hamidi et al., 2022) and a minor pest of other crops including apples and kiwis (Blanc, 1988). ...
Palomena prasina, the green shield bug (GSB), is widely distributed in the Eurosiberian region. In the Southwest of France, it is considered as a serious pest of hazelnuts, its feeding punctures lead to blank hazelnuts and kernel necrosis, causing heavy losses in commercial orchards. To date, no Integrated Pest Management strategy is available to control P. prasina. Control strategies often focus on the pests' spring-summer ecology, when they are in the field or in the vicinity of crops. However, the abundance of pest populations in crops is also related to their autumn-winter ecology. The present work focussed on the autumn-winter ecology of P. prasina to identify new opportunities for this pest suppression. We investigate (i) where P. prasina overwinters, (ii) if it aggregates in its overwintering sites and (iii) if it mates while overwintering. Samples were collected over a 2-year period in different ecosystems (forests, hedges, orchards), in human made structures and habitats (litter, bushes/trees, dead trees). The reproductive status of GBS individuals was monitored in winter, and in spring when they emerged from overwintering sites. Our results show that 97% P. prasina adults overwinter in the leaf litter of orchards and natural ecosystems and that 70% overwinter individually. The abundance of GSB in those sites is negatively correlated with litter temperature and positively correlated with humidity levels. Furthermore, adults only mate after leaving their overwintering site. Finally, unexpectedly, there was an important number of over-wintering adults hosting endoparasitoids (32%). The fact that GSB overwinters alone in the leaf litter means controlling its populations by destroying the overwintering sites is not a solution. All the same, our results point out some promising lines of research for developing methods to control P. prasina. First, the emergence traps, in particular the cone traps, proved efficient for collecting emerging adults and could be considered for monitoring. Moreover, our observations suggest the existence of long-range mating signals that could be exploited for trapping. Last but not least, the important number of overwintering parasitised adults is a potential biocontrol avenue.
... More broadly, categories and rates of damage may vary according to the phenology of the fruit, the species of insect and their developmental stage (Bosco et al., 2018;Hamidi et al., 2022;Hedstrom et al., 2014). The occurrence of true bug species and their impact on French hazelnuts have been poorly studied. ...
... To assess the phenological development stage of the hazelnuts, 10 developing nuts to mature nuts were collected weekly from the trees bearing the sleeves. The kernels were measured using a caliper following the protocol of Hamidi et al. (2022). Hazelnut phenology was classified in four main stages of development following the hazelnut BBCH scale (Paradinas et al., 2022): pre-expansion, shell expansion, kernel expansion and kernel maturation (Table 1). ...
Since 2015, the number of hazelnuts damaged by insects in France has increased exponentially. Palomena prasina, Pentatoma rufipes (Hemiptera: Pentatomidae), and Gonocerus acuteangulatus are common insect species on hazel trees. In France, their pest status is unclear, and consequently limited data are available on their impact on French hazelnut cultivars. In 2016 and 2017, bugs were collected in orchards, and in 2018, specimens were isolated from hazelnut branches in net sleeve bags at different developmental stages throughout the season. At harvest, nuts shells were removed, and symptoms of feeding analyzed. Pe. rufipes, Pa. prasina, and G. acuteangulatus represented 34, 28, and 6%, respectively, of all the bugs found in hazel orchards in 2016. In 2017, Pe. rufipes represented only 5%, while Pa. prasina was 48%, and G. acuteangulatus was 29%. While P. prasina and G. acuteangulatus are well-known as hazelnut pests in other areas, populations of P. rufipes are more erratic. Pe. rufipes caused the same amount of damage as Pa. prasina even though it penetrated deeper for feeding. Blank nuts, shrivelled, and corked kernels were the main injury symptoms. Brown spots caused by feeding mainly appeared during kernel expansion. However, white spots occurred when bugs fed on the kernels later in the season when they were fully developed. The study shows that Pa. prasina and Pe. rufipes are secondary hazelnut pests and need to be carefully monitored.
... Often, the altering phenomena generated in the orchard can amplify their detrimental effects during postharvest storage. One of the most detrimental alterations to hazelnut quality is caused by a group of insects belonging to the family of Coreidae (Gonocerus acuteangulatus) and Pentatomidae (Nezara viridula, Palomena prasina) [3]. In the last years, the problem has been exacerbated by the wide colonization of Europe and America areas by Halyomorpha halys (fam. ...
... On hazelnuts, stink bugs can cause different types of damage, depending on the stage of development in which the fruit is hit. In particular: i) if the insect bites the fruit in the pre-expansion phase of the shell, hazelnuts will be almost certainly subject to drop or traumatic abortion; ii) if the fruit is bitten while the shell is expanding, a traumatic abortion of the kernel will almost always occur, therefore shells will be empty at harvest; iii) if the fruit is hit during the kernel expansion or the ripening phase, kernels will be shrivelled or they will present a high incidence of the characteristic off-flavour defined as "cimiciato" or "corked" [3][4][5][6]. By visual inspection, cimiciato defect can appear as one or more spots on the kernel surface (external or visible cimiciato) or the damage can be located inside the kernel, and this prevents it to be detected visually, but the injure becomes visible only after opening the fruit in two halves (hidden or internal cimiciato) [6]. ...
The development of new non-invasive approaches able to recognize defective food is currently a lively field of research. In particular, a simple and non-destructive method able to recognize defective hazelnuts, such as cimiciato-infected ones, in real-time is still missing. This study has been designed to detect the presence of such damaged hazelnuts. To this aim, a measurement setup based on terahertz (THz) radiation has been developed. Images of a sample of 150 hazelnuts have been acquired in the low THz range by a compact and portable active imaging system equipped with a 0.14 THz source and identified as Healthy Hazelnuts (HH) or Cimiciato Hazelnut (CH) after visual inspection. All images have been analyzed to find the average transmission of the THz radiation within the sample area. The differences in the distribution of the two pop- ulations have been used to set up a classification scheme aimed at the discrimination between healthy and injured samples. The performance of the classification scheme has been assessed through the use of the confusion matrix on 50 samples. The False Positive Rate (FPR) and True Negative Rate (TNR) are 0% and 100%, respectively. On the other hand, the True Positive Rate (TPR) and False Negative Rate (FNR) are 75% and 25%, respectively. These results are relevant from the perspective of the development of a simple, automatic, real-time method for the discrimination of cimiciato-infected hazelnuts in the processing industry.
... Although a number of studies link the activity of true bugs with damage to nuts (Tavella et al., 2001;Tuncer et al., 2005;Hedstrom et al., 2014), the identification of the most susceptible phenological stages is still being explored (Hamidi et al., 2022). This study explores this topic, focusing on the damaging activity of three of the most destructive true bugs in two experimental fields: G. acuteangulatus and N. viridula in an experimental field in Viterbo (Italy), and P. prasina in an experimental field in Tarragona (Spain). ...
Hazelnut cultivation is continuously exposed to biotic adversities, with insect pests typically causing considerable production losses. Most of the damage is the result of feeding activity of ‘true bug’ species (Hemiptera: Heteroptera), which affects both nut quality and quantity. True bugs can cause the traumatic abortion of cotyledon tissues or other changes in the nut. The latter consists of necrosis of the kernel with the appearance of black or white spots and shrivelling. The type of damage is related to the timing of the feeding activity and the phenological stage of the nuts. This study aims to evaluate the relationship between the nut phenological stages and some of the most important true bug species in two different districts where European hazelnuts are produced. To pursue this aim, an experiment was conducted in the Tarragona hazelnut district (Spain) and in the Viterbo hazelnut district (Italy). Hazelnut plants were selected, and some branches were wrapped with net sleeves. In each net sleeve, Palomena prasina, Gonocerus acuteangulatus, and Nezara viridula adults were inserted when the nuts reached different stages of phenological development. As a result, two developmental stages of the kernel were identified during which the feeding activity of the true bugs causes traumatic abortion and ‘cimiciato’, respectively. According to the phenological scale developed by IRTA, these two stages are g2/G1 and G4/G5. These results are of great importance in the development of control strategies and the information provided will be helpful in reducing the number of treatments required to control true bugs.
... Organic management would be considered as viable only with good management of weeds, suckers and insects using various techniques. Concerning insect defects, several authors described kernel and in-shell symptoms caused by stink bugs or nut weevils (Germain and Sarraquigne, 2004;Moraglio et al., 2009;Hedstrom et al., 2014;Hamidi et al., 2022). These symptoms can range from bud fall to empty hazelnuts and kernel necrosis . ...
In France, organic hazelnut production is a real challenge. Considering the lack of organic solutions to limit insect pests in orchards, yield and nut quality could be impacted. This trial aims at evaluating: i) tree growth and nut productivity; ii) nut quality; iii) abundance of insect pests; and iv) soil insect biodiversity under organic and conventional orchard management. Trees were significantly taller and bigger in a conventional orchard than in an organic orchard (291 cm height and 72.9 mm diameter under conventional vs. 196 cm height and 43.3 mm diameter under organic). In the organic orchard, the yield was low (0.231 t ha-1), while in the conventional system, the yield was 1.91 t ha-1 during the 6th year. Concerning insect pests, few stink bug species (Hemiptera) were observed in conventional orchards. Three Gonocerus acuteangulatus were observed in both orchards, one in the organic and two in the conventional orchard. One individual of Palomena prasina, and one individual of Peribalus strictus were identified in the conventional orchard while five individuals of Nezara viridula were identified in the organic orchard. Stink bug damage ranged from 4 to 14.5% in organic orchards and from 0.4 to 4.9% in conventional orchards over the three harvests. While no nut weevils were collected in the orchards, the observed damage of Curculio nucum on nuts was 0.47-1.55% in the organic and 0.17-0.37% in the conventional orchards. Finally, in the soil, a larger number of insects were collected in the organic orchards than in the conventional orchards, respectively 17.2 vs. 5.7 individuals per soil sample in 2019, and 10.2 vs. 8.9 in 2020. The macrofauna was distributed into 3 classes, scavengers (73 vs. 68%), predators (12 vs. 8%) and harmful (15 vs. 24%), respectively, in organic and conventional orchards. To conclude, while the soil biodiversity was better in the organic orchard, soil preparation for tree establishment seems to be essential for improving tree growth and yield under organic systems.
... More than 15 stink bug species (Hemiptera: Pentatomidae, Coreidae, and Acanthosomatidae) have been found in hazelnut orchards of different hazelnut countries, affecting the hazelnut production qualitatively and quantitatively (Tavella et al., 1997;Tavella et al., 2001;Tuncer et al., 2005;Ozdemir et al., 2022). Stink bugs' damage can result in fruit abortion during the early season, empty and gray-black nuts during the early nut development stage, shriveled kernels during the early kernel development stage, and corked kernels during the kernel expansion period (Kurt, 1975;Tavella et al., 2001;Tuncer et al., 2005;Saruhan and Tuncer, 2010;Hamidi et al., 2022). Their damage is usually unnoticed before harvest since fruit abortion and empty nuts without kernels are not linked with bug activity by most farmers. ...
The green shield bug (GSB) (Palomena prasina, Hem.: Pentatomidae) is one of the most important pests of hazelnut in Turkish hazelnut orchards. This harmful insect causes serious yield and quality losses by feeding directly on fruits every year. Their feeding on hazelnut fruits may result in nut abortion (empty nuts) in early season and cause shriveled and corked kernels in kernel expansion period. Insect pest management must be decided by depending on insect population level in field according to integrated pest management concept. Economic injury level (EIL) and economic threshold (ET) are the main essential points that must be considered in decision for pest control. Thus it can be possible to protect the natural environment from unnecessary pesticide applications and the growers from high production costs. Therefore determining of economic decision levels for control action of pests is critical. Especially, this is an important issue for hazelnut that are grown in hundreds of thousands hectares area in Turkey and for the GSB that is serious pest needing a couple of chemical application in a year. The economic decision levels vary mainly due to insect species and its damage potential, crop value in market and control costs so to years and countries. Therefore it is changeable in time. This study aimed to calculate the EIL and ET values for GSB control action in hazelnut orchards of Turkey by using new economic market data. Yield loss caused by one individual of GSB was calculated from previous research data done by authors. Direct yield loss and quality/quantity losses of damaged kernels calculated separately and then combined. The data including crop value and control costs necessary for calculation was updated from free market. In calculation of EIL/ET, the most common formula (EIL= C/ VxbxK) was used. As a result, economic threshold was found 3.8 insect/decare (0.1 ha) for K=1 value and 4.76 insect/decare for K=0.8 value, for single insecticide application. When ET values were converted in traditional Turkish approach that is special for hazelnut orchards; ET values for K=1 and K=0.8 were 0.76 insect/ 10 “hazelnut “ocak” (traditional growing of hazelnut plants together) and 0.95 insect/ 10 “ocak” respectively. If 2 applications per year for GSB was considered, ET values were found as 9.47 insect/ da, about 10 insect/da and 1.9 insect/ 10 “ocak” for Turkey, about 2 insect/10 ocak.
... More species/genera are reported in Table 1 which could be involved in defensive mutualism on hazelnut; this is the case of E. nigrum, Chaetomium, , and Cordyceps, Hirsutella, Simplicillium as entomopathogens (Nicoletti & Becchimanzi 2020). Particularly, the role of endophytic entomopathogens is increasingly appreciated for its general impact in plant protection (Mantzoukas & Eliopoulos 2020;Nicoletti & Becchimanzi 2020, 2021; on hazelnut, it deserves to be carefully investigated with reference to the high economic incidence on production by insects such as weevils (Curculio spp.) and stink bugs (Heteroptera: Pentatomidae, Coreidae) (Hamidi et al. 2022;Shanovich & Aukema 2022). ...
Results of a vast research activity carried out worldwide in the last decades have demonstrated that endophytic fungi hold a fundamental role in improving plant fitness based on their aptitudes as growth promoters and/or defensive mutualists. These properties may have applicative perspectives in crop production, particularly for tree species such as hazelnut (Corylus avellana), which is mostly cropped extensively in semi-natural contexts of highland regions throughout the temperate zones. The available data on the occurrence, ecological roles, and applications in biotechnology of endophytic fungi associated with hazelnuts are revised in this paper in view to provide a reference supporting future investigations and projects aimed at exploiting the potential of this component of the plant microbiome.
... The most important factor influencing crop yield and quality in plants is probably environmental stresses caused by climate change; therefore, it is very important and realistic to focus on the effects of environmental stressors on the vegetative and generative development of hazelnut in studies conducted to increase yield [6]. From the point of view of reproductive biology, the most important factor affecting the yield of hazelnut is delayed fertilization [7]. Since the ovary is not sufficiently differentiated at the time of pollination, pollen grains must wait for the ovary to mature for about 2-3 months [8,9]. During this period, the success of pollination and fertilization is at risk since pollen grains can lose their efficiency by being exposed to various environmental stresses, such as temperature, drought, salinity, air pollutants and ultraviolet radiation [10]. ...
Increasing ultraviolet (UV) radiation is expected to become a problem in hazelnut cultivation. The aim of this study is to examine the effects of UV-B on hazelnut pollen. To this end, the pollens were exposed to UV-B for 1, 2, and 3 h at distances of 10, 20, 30, and 40 cm. Groups treated for 2 h at 20 cm and 3 h at 10 and 20 cm were identified as the most affected based on the results of viability, germination, and tube elongation. Further studies on these groups showed that UV-B does not change the DPPH radical scavenging activity for all groups. However, total phenolic compounds decreased after 3 h of treatment at 10 and 20 cm, while total flavonoid compounds decreased after all treatment groups. The UV-B absorbance of cytoplasmic and cell-wall-bound fractions decreased for all groups. The UV-B absorbance of the sporopollenin-derived fraction increased after 2 h of treatment at 20 cm but decreases after treatment for 3 h at 10 and 20 cm. In summary, exposure to UV-B for different times and distances adversely affected pollen grains in terms of pollen viability , germination rate, tube length, and the level of antioxidant molecules and UV-absorbing compounds .
... The most important factor influencing crop yield and quality in plants is probably environmental stresses caused by climate change; therefore, it is very important and realistic to focus on the effects of environmental stressors on the vegetative and generative development of hazelnut in studies conducted to increase yield [6]. From the point of view of reproductive biology, the most important factor affecting the yield of hazelnut is delayed fertilization [7]. Since the ovary is not sufficiently differentiated at the time of pollination, pollen grains must wait for the ovary to mature for about 2-3 months [8,9]. During this period, the success of pollination and fertilization is at risk since pollen grains can lose their efficiency by being exposed to various environmental stresses, such as temperature, drought, salinity, air pollutants and ultraviolet radiation [10]. ...
Increasing ultraviolet (UV) radiation is expected to become a problem in hazelnut cultivation. The aim of this study is to examine the effects of UV-B on hazelnut pollen. To this end, the pollens were exposed to UV-B for 1, 2, and 3 h at distances of 10, 20, 30, and 40 cm. Groups treated for 2 h at 20 cm and 3 h at 10 and 20 cm were identified as the most affected based on the results of viability, germination, and tube elongation. Further studies on these groups showed that UV-B does not change the DPPH radical scavenging activity for all groups. However, total phenolic compounds decreased after 3 h of treatment at 10 and 20 cm, while total flavonoid compounds decreased after all treatment groups. The UV-B absorbance of cytoplasmic and cell-wall-bound fractions decreased for all groups. The UV-B absorbance of the sporopollenin-derived fraction increased after 2 h of treatment at 20 cm but decreases after treatment for 3 h at 10 and 20 cm. In summary, exposure to UV-B for different times and distances adversely affected pollen grains in terms of pollen viability , germination rate, tube length, and the level of antioxidant molecules and UV-absorbing compounds .
... Palomena prasina was cited as a very occasional pest in southeastern France and around the Mediterranean (Galet, 1982); the species is currently an emerging pest in southern France but mainly affects apples and hazelnuts (Hamidi et al., 2022;Streito and Bout, 2019). Nezara viridula is an exotic pest species currently on the rise in France (Streito and Bout, 2019) but not referenced as a serious pest of grapevines (McPherson, 2018). ...
Here we report the first detection of Halyomorpha halys (Stål, 1855) in Bordeaux vineyards. The species is native to Eastern Asia and was introduced to France in 2012. Halyomorpha halys is highly polyphagous and causes significant damage to various crops, including grapevines. From 2018 to 2020, Pentatomidae species were collected in vineyards in the Bordeaux region. In 2020, the first nymphs and adults of H. halys were identified in the plot centres. The study emphasizes the need for field population monitoring in risk assessment and, consequently, risk management.
We present a genome assembly from an individual female Gonocerus acuteangulatus (the Box Bug; Arthropoda; Insecta; Hemiptera; Coreidae). The genome sequence is 1,106.2 megabases in span. Most of the assembly is scaffolded into 10 chromosomal pseudomolecules, including the X sex chromosome. The mitochondrial genome has also been assembled and is 15.31 kilobases in length. Gene annotation of this assembly on Ensembl identified 22,286 protein coding genes.
European hazelnut cultivars are grouped by comparing their phenological development to a few reference cultivars such as ‘Barcelona’, ‘Tonda di Giffoni’ and ‘Tonda Gentile delle Langhe’. The cultivars are described as earlier or later than the references for blooming, and harvest time. BBCH scales describe the plant phenological stages according to a numerical scale. The conversion of alphanumerical codes to a fully numerical code would allow easier phenological computer data analysis. While the scale is widely used in predictive agriculture, it needs to be updated for hazelnut cultivation considering current knowledge. The aim of this study was to present a consolidated BBCH scale for European hazelnut phenotyping. The plant phenology was divided into eight growth stages, from bud development to senescence as follows: stage 0, bud development; stage 1, leaf development; stage 3, stem elongation; stage 5, male inflorescence emergence; stage 6, male and female flowering; stage 7, fruit development; stage 8, fruit ripening; and stage 9, dormancy or winter rest. The eight growth stages were subdivided into 53 specific sub-stages corresponding to each specific phenophase of the hazelnut growing season. This updated scale is easily usable once the translation between historical and BBCH scales are grasped by the observer. The phenological stages of hazelnut can be described from the male inflorescence development (stage 5) in one year until fruit ripening (stage 8), which occurs in the next year.
The yellow marmorated stink bug, Erthesina fullo (Thunberg, 1783), is a major pest of certain tree fruits in Northeast Asia. To better understand the feeding mechanism of E. fullo, the fine structure of the mouthparts, including the distribution and abundance of sensilla, are examined with scanning electron microscopy (SEM), and their functions are observed directly under laboratory conditions. The feeding performance is described in detail and illustrated for the first time. The adult feeding process involves several steps, including exploring and puncturing of the host plant epidermis, a probing phase, an engorgement phase, and removal of the mouthparts from the host tissue. Proceeding from labium towards the mandibular stylets, the movement pattern becomes increasingly stereotypical, including the sensilla on the tip of the labium probing, the labium making an elbow-like bend between the first and second segment, the base of the stylet fascicle housing in the groove of the labrum, the mandibular stylets penetrating the site and maxillary stylets feeding. In terms of morphology, the mouthparts are similar to those of other Heteroptera, consisting of a triangular pyramidal labrum, a tube-like and segmented labium with a deep groove on the anterior side, and a stylet fascicle consisting of two mandibular and two maxillary stylets. The four-segmented labium has five types of sensilla basiconica, three types of sensilla trichodea, two types of sensilla campaniformia and 1 type of sensilla coeloconica. Among them, sensilla trichodea one and sensilla basiconica one are most abundant. The tripartite apex of the labium is covered with abundant sensilla trichodea three and a few sensilla basiconica 5. The mandibular stylet tips have two nodules preapically on the dorsal margin of the convex external surface, which may help in penetrating plant tissue and anchoring the mouthparts. The externally smooth maxillary stylets interlock to form a larger food canal and a smaller salivary canal. The structure and function of the mouthparts are adapted for the phytophagous feeding habit in this species. Similarities and differences between the mouthparts of E. fullo and those of other Heteroptera are discussed.
In the United States, California (CA) is the primary commercial producer of pistachio nuts, Pistacia vera L. (Anacardiaceae). The brown marmorated stink bug (BMSB), Halyomorpha halys (Stål) (Hemiptera: Pentatomidae), an invasive and polyphagous insect pest from Asia, has established in urban areas in several pistachio-growing counties in CA. Breeding BMSB populations have not been detected in commercial pistachio acreage. However, the detection of BMSB in Kern and Fresno counties, major Kerman pistachio producing areas in CA, underscored key knowledge gaps on BMSB ecology in CA and motivated investigations on the susceptibility of pistachio nuts to BMSB feeding. Laboratory feeding trials conducted in quarantine under permit indicated that adult BMSB stylets can penetrate developing pistachio shells and associated feeding was correlated with kernel necrosis for nuts collected mid to late season (June to August 2016). Feeding damage estimates indicated that higher levels of kernel injury were associated with female BMSB when compared to feeding by male BMSB. These results suggest that there is probable risk of feeding damage to field grown pistachios from BMSB. The implications of this study for BMSB pest management in the CA pistachio system and future research directions are discussed.
Following its first detection, Halyomorpha halys has become a key pest in many crops in NW Italy. In this area, one of the most important crops is hazelnut, in which the species can cause severe damage through feeding on nuts. Therefore, semi-field trials were carried out in NW Italy to compare the harmfulness of H. halys with that of the local hazelnut bug species, such as Gonocerus acuteangulatus, Nezara viridula, and Palomena prasina. Additionally, a 2-year field survey was conducted in hazel groves in NW Italy and W Georgia, another important hazelnut cropping area, to assess the presence and abundance of the new invasive species and to evaluate the damage at harvest. Monitoring was carried out by plant beating and by commercial traps throughout the growing season. In semi-field trials, H. halys was the most harmful species, causing the highest damage in kernels, and was able to survive and reproduce at higher rates. During field surveys in NW Italy, H. halys was sampled in groves late in the season in 2015 and, with higher populations, throughout the season in 2016. In W Georgia, bug population levels consistently increased in the 2-year period, resulting in a significant increase in damage at harvest in 2016. A similar trend is hence expected also in NW Italy in the following years. Moreover, data on individuals collected in different points of the hazelnut groves confirmed the border-driven behavior of this pest, leading to consideration of potential integrated pest management solutions.
Mouthpart structure and feeding behavior in the temperate firebug, Pyrrhocoris sibiricus Kuschakevich, an important pest that feeds on seeds of leguminous and gramineous plants, are described for the first time. Mouthparts were observed using scanning electron microscopy to examine the external morphology, distribution and abundance of sensilla on mouthparts. Feeding performance by adults on both seeds and shoots were observed using a binocular microscope. The four-segmented labium contains 3 types of sensilla trichodea, 3 types of sensilla basiconica, 1 type of sensilla placodea and 1 type of sensilla campaniformia. Among them, sensilla trichodea are most abundant. The tripartite apex of the labium consists of two lateral lobes and an apical plate. Each lateral lobe possesses a field of 12 thick-walled uniporous peg sensilla and long non-porous hair sensilla. The mandibular stylet tips have three central teeth and two pairs of lateral teeth, which may help in penetrating hard seed coats. A series of scale-like projections are present on the inner surface of the mandibular stylets. The externally smooth maxillary stylets interlock to form a larger food canal and a smaller salivary canal, and there are five tubercles near the tip of the right stylet. Cross-sections of the stylet fascicle show that each mandibular stylet has a dendritic canal. The adult feeding process involves several steps, including exploring and puncturing of the host epidermis, a probing phase, an engorgement phase, and removal of the mouthparts from the host tissue. The structure and function of the mouthparts are adapted for the seed feeding habits.
There are a lot of insects and mite pests in hazelnut orchards in Turkey. Most pests affect hazelnut production through direct or indirect injury, but a few affect kernel quality and reduce yields by feeding on the nuts themselves.recent years, hazelnut exporters have begun to complain about this kind of damage reducing kernel quality because it has a negative effect on exports. It was established that more than 15 bug species could affect kernel quality (Heteroptera: Pentatomidae, Coreidae and Acanthosomatidae) in Turkish hazelnut orchards. This study determined fluctuations in the population of these bugs in six hazelnut orchards and on three main cultivars. Palomena prasina and Gonocerus acuteangulatus were found to be the main species. The pest population was above the economic damage threshold.a cage experiment with P. prasina, three types of injury were determined.addition to field and cage experiments, quite significant data about bug-related kernel damage were obtained from hazelnut factories. Kernel damage varied according to variety, locality and sample, reaching levels of around 20% of the total crop.
HIGHLIGHTS In an abortive ovary of hazel, an integument seldom differentiated and a mature embryo sac never developed.
In an abortive ovary of hazel, pollen tube growth was arrested at the style base about 40 days after blooming. Thus, fertilization of the ovule was precluded.
Ovary abortion in the four hybrid cultivars was indicated to be associated with insufficient resource availability to support fruit set by all flowers, whereas ovary abortion in C. heterophylla was at least partly determined by pollen availability.
In Northeast China, a high frequency of ovary abortion contributes to serious losses in yield of hazelnut. The development of pistillate inflorescences and fruit clusters of four large-fruited hybrid hazel cultivars and the small-fruited Corylus heterophylla were used to study ovary abortion and its possible causes during the progamic phase in hazel. The average number of pistillate (ANP) flowers per inflorescence and average number of fruit (ANF) per cluster of four hybrid hazel cultivars were 7.6–8.5 and 2.4–3.0 respectively; in C. heterophylla, its ANP and ANF was 5.8–6.2 and 3.5, respectively. The total drop varied from 50 to 67%. Ovary abortion in hazel initiated from about 30 days after blooming. The percentage of abortive ovaries (PAO) in the four hybrid hazel cultivars ranged from 63 to 72%, and was significantly higher than that of C. heterophylla (29–42%). Only the abortive ovary ratio of C. heterophylla was significantly reduced after artificial pollination. Fruit number per cluster was positively and negatively correlated with yield and nut mass, respectively. In abortive ovaries, the diameter remained less than 2 mm during the entire fruit development, an integument seldom differentiated and a mature embryo sac never developed. In addition, pollen tube growth was arrested at the style base about 40 days after blooming. Thus, fertilization of the ovule was precluded. Compared with abortive ovary, starch content in developing ovary of four hybrid hazel cultivars and C. heterophylla were significantly higher. This study suggests that abortive ovary was incapable to finish fertilization process due to the absence of mature embryo sac and arrested pollen tubes, and this is likely associate with insufficient resource availability to support fruit set by all flowers in four hybrid hazel cultivars, whereas ovary abortion in C. heterophylla is at least partly determined by pollen availability.
California almonds [Prunus dulcis, syn. P. amygdalus, P. communis] possess a moderately lignified 'paper' shell rather than the stony, peach-pit type shells common to European and Asian cultivars. At nut maturity, more than 70% of shells of the principal California cultivar Nonpareil can be split. Use of a mechanical shaker to harvest nuts increased the proportion of nuts with split shells by 40% when compared to hand harvest. All shell splitting occurred at the ventral suture with ∼ 80% of the splits occurring at the site of the degenerating funiculus leading to the aborted or secondary ovule. Remaining splits occurred near the site of the funiculus feeding the viable ovule, and only rarely at the suture line. Abortion of one of the two ovules in the almond ovary is often initiated at or shortly after bloom, and so the final site of shell splitting appears to be predetermined early in fruit development. Measurements of the strength of the inner endocarp wall at 50 days after flowering showed distinct weaknesses in the areas of the developing funiculi. Similarly, damage to the developing kernel at 60 days after flowering by the leaffooted bug (Leptoglossus clypealis Heiderman) occurred along the ventral suture, with 80% of the damage located at the point of attachment of the secondary funiculus.
Halyomorpha halys Stål, the brown marmorated stink bug (Hemiptera: Pentatomidae), is an invasive pest with established populations in Oregon. The generalist feeding habits of H. halys suggest it has the potential to be a pest of many specialty crops grown in Oregon, including hazelnuts, Corylus avellana L. The objectives of this study were to: 1) characterize the damage to developing hazelnut kernels resulting from feeding by H. halys adults, 2) determine how the timing of feeding during kernel development influences damage to kernels, and 3) determine if hazelnut shell thickness has an effect on feeding frequency on kernels. Adult brown marmorated stink bugs were allowed to feed on developing nuts for 1-wk periods from initial kernel development (spring) until harvest (fall). Developing nuts not exposed to feeding by H. halys served as a control treatment. The degree of damage and diagnostic symptoms corresponded with the hazelnut kernels' physiological development. Our results demonstrated that when H. halys fed on hazelnuts before kernel expansion, development of the kernels could cease, resulting in empty shells. When stink bugs fed during kernel expansion, kernels appeared malformed. When stink bugs fed on mature nuts the kernels exhibited corky, necrotic areas. Although significant differences in shell thickness were observed among the cultivars, no significant differences occurred in the proportions of damaged kernels based on field tests and laboratory choice tests. The results of these studies demonstrated that commercial hazelnuts are susceptible to damage caused by the feeding of H. halys throughout the entire period of kernel development.
© 2014 Entomological Society of America.
Unlike most angiosperms, in which fertilization occurs within several days after pollination, fertilization in hazel (Corylus Spp.) is delayed by two to three and a half months. However, the female inflorescences or young fruits are too hard or lignified to be dissected according to regular paraffin sectioning technique. So, what the nature of development during the extended progamic phases of hazel remains unknown. The female inflorescence development and pollen tube growth mode during the delayed fertilization stage in hazel were investigated by improved paraffin sectioning and aniline blue staining of pollen tubes. The results showed ovaries and ovules of hazel were invisible at the time of blooming. Early ovary and ovule primordium began to form from 15 to 20 days after blooming, respectively. Integument and mature embryo sacs differentiated from the nucellus on 40th and 55th day after blooming, respectively. Pollen tubes were retarded in the bottom of the style or the pollen tube cavity (PTC, a specifical lignified cavity structure at the bottom of style for pollen tube to rest during progamic phase) for about 26 days. Then, the pollen tubes were observed to leave the PTC and began to enter the ovary. After that, a single pollen tube passed through the vicinity of the micropyle. Finally, pollen tubes turned a corner and penetrated the embryo sac through the tissue of the chalaza instead of micropyle on 52 and 55 days after blooming, respectively. The results of more in-depth information will be beneficial to better understanding of the delayed fertilization process in hazel.
Rostrum length, mandible serration, and food and salivary canals areas of selected species of stink bugs (Heteroptera, Pentatomidae). Laboratory studies were conducted to compare rostrum length morphology of mandible serration and area of food and salivary canals of Dichelops melacanthus (Dallas) (Dm), Euschistus heros (F.) (Eh), Nezara viridula (L.) (Nv), and Piezodorus guildinii (Westwood) (Pg) (Heteroptera: Pentatomidae). Nv showed the longest (5.9 mm) and Pg the shortest (3.5 mm) rostrum length; Dm and Eh were intermediate. Length and width of mandible tip areas holding serration was bigger for Nv (106.0 and 30.2 pm, respectively) and smaller for Pg (71.1 and 23.7 mu m), with all species having four central teeth and three pairs of lateral teeth. The inner mandible surface showed squamous texture. Cross-section of food and salivary canals (Fe and Sc) indicated greater area for Nv and Dm compared to Eh and Pg; however, the ratio Fc/Sc, yielded the highest relative area for Pg.
The paper reviews the data on diapause and related phenomena in stink bugs (Heteroptera: Pentatomidae). Using stink bugs as examples, the consecutive stages of the complex dynamic process of diapause (such as diapause preparation, induction, initiation, maintenance, termination, post-diapause quiescence, and resumption of direct development) are described and discussed. Out of 43 pentatomid species studied in relation to diapause in the Temperate Zone up to date, the majority (38 species) overwinter as adults, two species—as eggs, and another two species—as nymphs. Pentatoma rufipes is believed to be able to overwinter at different stages of its life cycle. Less than 5 % of pentatomid species are probably able to overwinter twice. Only five species have obligate diapause, others have the facultative one. Day-length and temperature are the main diapause inducing factors in the majority of species. The role of food in the control of seasonal development is essential in the pentatomid species feeding on plant seeds. In different species, different stages are sensitive to day-length. Some pentatomids retain sensitivity to photoperiod even after diapause, others lose it and become photo-refractory (temporarily or permanently). In Pentatomidae, such seasonal adaptations as photoperiodic control of nymphal growth rates, seasonal body colour change, migrations, and summer diapause (aestivation) are widely represented, whereas wing and/or wing muscle polymorphism has not been reported yet. In the subfamily Podopinae, induction of facultative reproductive winter diapause is under the control of photoperiod and temperature. All species feed on seeds and their seasonal development to a great extent reflects availability of food. However, the same food preferences and pattern of seasonal development are also characteristic to many species from the subfamily Pentatominae. All species of the subfamily Asopinae are predators. Among them, Picromerus bidens and Apateticus cynicus have obligate embryonic winter diapause, which is rear among true bugs. At the same time, A. cynicus and Podisus maculiventris belong to the same tribe but have different types of diapause: obligate embryonic diapause in A. cynicus and facultative adult diapause in P. maculiventris. Other Asopinae species studied up to date have facultative adult diapause controlled by photoperiod and temperature with probably only one exception: in Andrallus spinidens, adult diapause is controlled by temperature, and photoperiod plays only a secondary role. Thus, in spite of the similar habits and feeding types among Asopinae, the species of this subfamily have different types of diapause and the latter is controlled by different factors. In the subfamily Pentatominae, most species overwinter as adults and induction of their diapause is controlled by the long-day type photoperiodic response, in spite of the differences in their feeding preferences (within phytophagy). However, there are some exceptions in this subfamily, too: Palomena prasina, P. angulosa and Menida scotti have obligate diapause, which conditions univoltinism in these pentatomids. In M. scotti, only females have obligate adult diapause, whereas males remain physiologically active through the whole winter, this pattern being unusual for Heteroptera. The univoltine seasonal cycle of this species with summer diapause (aestivation) and apparent migrations is similar to that of shield bugs (Scutelleridae). According to the analysis of seasonal development, the evolution of seasonal adaptations in Pentatomidae does not directly reflect their phylogeny. However, individual genera, small tribes or even subfamilies have similar complexes of seasonal adaptations. At the same time, Pentatominae is a large and apparently collected taxon, but most of species in this subfamily have the same facultative adult diapause.
"Large bug" damage to pistachio nuts varies by season, as well as among in- sect species and development stages, with larger bugs typically causing more damage than smaller bugs. We investigated pistachio damage by three large bug species (leaffooted bug, redshouldered stink bug and flat green stink bug) at different devel- opment stages and throughout the season, using field surveys and cage studies. Before fruit set occurs in June, most damaged nuts are dropped from the cluster without reducing fruit load. The midseason period (June to July) is the most critical because the damaged nuts remain in the cluster. After shell hardening, the kernel is largely protected from bug feeding.
The present paper describes the sensory structures on the apical segment of the labium in fifteen fulgoromorphan families (Hemiptera: Fulgoromorpha), using the scanning electron microscope. Thirteen morphologically distinct types of sensilla are identified: five types of multiporous sensilla, four types of uniporous sensilla and four types of nonporous sensilla. Three subapical sensory organ types are also recognized, formed from one to several sensilla, each characteristic of a family group. Sensilla chaetica (mechanoreceptive sensilla) fall into three categories dependent on length and are numerous and evenly distributed on the surface of the labium except where they occur on specialized sensory fields. The planthopper morphological ground plan is represented by two apical pair of sensory fields (dorsal and ventral) on which 11 dorsal pairs of sensilla (10 peg-like pairs + 1 specialized pair dome or cupola-like) and 2 ventral pairs of sensilla basiconica occur. Two main patterns (cixiid and issid) together with more specialized ones (derbid, lophopid, flatid and fulgorid) are reported. Disparity and diversity of the sensory structures are analyzed from a taxonomic and functional perspective. A gustatory function is provided for several chemoreceptive labial sensilla, as in the antennal flagellum sensilla in some other Hemiptera. This represents a more recently evolved function for the planthopper labium. Finally, further lines of study are suggested for future work on the phylogeny of the group based on the studied characters.
This study was carried out in Samsun during a 2-year period to examine the relationship between reproductive and yield loses in the ‘Tombul’ and ‘Palaz’ hazelnut cultivars. In hazelnuts, male and female flowering occur in winter after the breaking of inflorescence dormancy. In the present study, growth of the ovary of the hazelnut started in April and continued until mid-June. At the time of flowering the ovary did not form. The ovule growth showed a rapid increase at the end of June. Change in the diameter of the ovary and ovule with time showed a simple sigmoid growth curve. Fertilization occurred during the period between mid-May and the beginning of June, namely, 3.5–5 months after pollination. At this time, the diameter of the nut was 9.54 mm. Twin kernel was not observed. The ratio of double kernels was close to zero. The time period from fertilization to harvest was 89 days in 1997 and 96 days in 1998 for Tombul cultivar. For the Palaz, this period was 84 days in 1997 and 86 days in 1998. The rate of pistillate flower clusters which dropped in April–May was more than those dropped in June–August.
Gonocerus acuteangulatus (Goeze) (Hemiptera Coreidae) and Eurygaster maura (L.) (Hemiptera Scutelleridae) can cause detri-mental effects on the yield quality of hazelnut and wheat, respectively, because of proteolytic enzymes injected into kernels via their saliva during the feeding activity. The research was carried out to develop an alternative rapid diagnostic method able to de-tect damage through the presence of bug proteinase in hazelnut and wheat kernels using biochemical markers; in particular, poly-clonal antibodies against salivary glands of Leptoglossus occidentalis Heidemann (Hemiptera Coreidae) and of E. maura were assayed to detect saliva in bug-damaged nut and wheat kernels. The promising results achieved are showed and discussed.
This book compiles for the first time all the current information on the electronic monitoring of the feeding behaviour of phytophagous true bugs, describing the mouthparts and modes of feeding of. It includes state-of-the-art illustrations of feeding sites on the various plant structures, and examines how the different feeding strategies are related to the variable waveforms generated using the electropenetrography (EPG) technique. Further, the book discusses the damage (physical and chemical) resulting from feeding activities, as well as the plant reactions to the damage. Covering in detail all EPG studies developed and conducted using true bugs published to date, it explores the use of electronic monitoring of feeding coupled with histological analyses to improve chemical and gene silencing (RNAi) strategies to control true bugs.
Stink bugs (Hemiptera: Pentatomidae) and related species continue to plague cotton, Gossypium hirsutum L. (Malvaceae), worldwide. Stink bugs utilize their stylets (housed within the rostrum) to feed upon cotton bolls and transmit pathogens that cause seed and boll rot of cotton. Stylet penetration potential of stink bugs is influenced by species and recent observations indicated a phenomenon whereby stink bugs with shorter rostra yielded deeper stylet penetration estimates. The objective of this study was to elucidate the relationship between rostrum length and known stylet penetration estimates for two pairs of similar‐sized pentatomid species: Chinavia hilaris (Say) vs. Euschistus servus (Say), and Oebalus pugnax (Fabricius) vs. Piezodorus guildinii Westwood. For each species, individual rostral segments were measured to yield total lengths, and measurements were compared against known stylet penetration estimates. Chinavia hilaris and P. guildinii have longer rostra than E. servus and O. pugnax, respectively, yet E. servus and O. pugnax yielded deeper stylet penetration estimates. Deeper stylet penetration by species with shorter rostra can be attributed to differences in the lengths of rostral segments 1 and 2. Euschistus servus and O. pugnax each had significantly longer rostral segments 1 and 2 than C. hilaris and P. guildinii, respectively. Also, the cumulative lengths of rostral segments 1 and 2 comprised a higher overall proportion of the entire rostrum length in E. servus and O. pugnax vs. C. hilaris and P. guildinii, respectively. Rostral segments 1 and 2 are instrumental in the feeding mechanics of these phytophagous species; it is clear that their greater length and their role in stylet penetration model calculations – including the lengths of segments 3 and 4 – override the presumption that total rostrum length equates to stylet penetration potential. This novel finding contributes to the general knowledge of stink bug feeding mechanics.
Members of the subfamily Asopinae (common names: predatory stinkbugs or soldier bugs) are set apart from the other pentatomid subfamilies by their essentially predaceous feeding habits. Asopine first instars do not attack prey and only need moisture, mainly plant juices, to develop. Although for some predatory stinkbugs partial development on certain plant foods has been observed, nymphs from the second instar on require animal food to complete development. Further, nymphs and adults are often observed to take up plant juices or free water in addition to feeding on prey, suggesting that metabolic water or that from prey is insufficient for survival (Schumacher 1910, for more details see Section 3.2). Unlike phytophagous pentatomids, predatory stinkbugs are characterized by having a crassate rostrum. The first segment is markedly thickened and free, only the base being embedded between the bucculae. This enables a fully forward extension of the rostrum and thus facilitates feeding on active prey. The bucculae form a rostral groove that does not reach the posterior margin of the head. The rostrum generally extends beyond the coxae of the middle legs, but never surpasses the base of the venter. The scutellum is mostly much shorter than the abdomen, but in some genera it is enlarged, covering most of the abdominal dorsum. The anterior tibiae have a short, acute spine on the lower surface (Schouteden 1907; Schumacher 1910; Miller 1956; DeCoursey and Allen 1968; Thomas 1992, 1994). McDonald (1966) stated that the genitalia of the Asopinae have no unique characters, although the asopine males are unique in combining the presence of genital plates (parandria) with a thecal shield.
Of the eight recognized subfamilies of stink bugs, only species of two subfamilies, Edessinae and Pentatominae, are serious crop pests. Because of their polyphagous feeding habits, stink bugs are serious pests in crops such as legumes, grasses, grains, vegetables and fruit and nut trees (Panizzi et al. (2000). In recent years, the incorporation of Bacillus thuringiensis genetically modified-based crops (Bt crops), primarily against lepidopteran pests, has led to a reduction in insecticide use. As a consequence, some stink bugs and mirids have increased their population levels, reaching outbreak levels (Green et al. 2001, Kennedy 2008, Lu et al. (2010). Additionally, extended non-tillage practices appear to contribute to the pervasive population rise in these insects (Chocorosqui and Panizzi 2004, Seffrin et al. (2006). Another recent phenomenon, which is related to climate change, is the invasion of temperate climate regions by tropical or subtropical species, such as Halyomorpha halys (Stal), Bagrada hilaris (Burmeister) and Piezodorus guildinii (Westwood) (Panizzi 2015). These situations challenge entomologists to develop efficient pest management strategies for stink bugs. 227In general, the management of stink bugs has been based on population control with insecticide applications, which have increased dramatically in recent years (Panizzi 2013). This practice is unsustainable over the long-term because of the known side-effects of synthetic insecticides
Activity-guided fractionation in combination with sensory analytics, LC-TOF-MS, and 1D/2D-NMR spectroscopy enabled the identification of the bitter tasting diarylheptanoids asadanin, giffonin P and the previously not reported (E)-7,9,10,13-tetrahydroxy-1,7-bis(2-hydroxyphenyl)hept-9-en-11-one and 4,12,16-trihydroxy-2-oxatricyclo[13.3.1.13,7]-nonadeca-1(18),3,5,7(20),8,15,17-heptaen as well as the yet unknown astringent compounds 2-(3-hydroxy-2-oxoindolin-3-yl) acetic acid 3-O-6´-galactopyranosyl-2“-(2“oxoindolin-3“yl) acetate and 3-(O-β-D-glycosyl) dioxindole-3-acetic acid in Cimiciato-infected hazelnuts exhibiting a bitter off-taste. Quantitative LC-MS/MS studies, followed by dose/activity considerations confirmed for the first time asadanin to be the key contributor to the bitter taste of Cimiciato-infected hazelnuts. Furthermore, quantitative studies demonstrated that neither the physical damage alone, nor a general microbial infection is able to initiate a stress-induced asadanin generation, but most likely either specific Cimiciato-specific microorganisms associated with the bugs, or specific chemical stimulants in the bugs’ saliva is the cause triggering asadanin biosynthesis. Finally, also germination was found for the first time to activate diarylheptanoid biosynthesis, resulting in higher contents of bitter tasting phytochemicals and development of the bitter off-taste.
Change of fat contents and fatty acids were analyzed during the fruit development period in the hazelnuts Tombul and Palaz cultivars. Palmitic acid in hazelnuts was the main saturated fatty acid followed by the stearic acid. The main unsaturated fatty acid in kernels of studied hazelnut cultivars was found to be oleic acid, followed by linoleic acid. But, linolenic acid was trace amount. Fat content has increased during the fruit development period and reached it's maximum at the date of harvest maturity. Palmitic (16:0) and stearic (18:0) acid contents have decreased at the beginning of the fruit development period (28.6.1995-12.7.1995) and then an important change have not occurred. Oleic (18:1) acid has increased regularly and reached maximum at the harvest date. Linoleic (18:2) acid has decreased parallel to the oleic (18:1) acid.
Fluorescence microscopy was used to study incompatibility in wild Corylus species. Selfpollinations as well as intraspecific and interspecific crosses were made in the laboratory. Clearly incompatible reactions were observed following nearly all self-pollinations, indicated by reduced pollen germination and pollen tubes that were short, usually "comma-shaped," often terminating in pronounced bulbs, and failing to penetrate the stigma. Both compatible and incompatible reactions were observed in intra-and interspecific pollinations with some reciprocal differences. Pollen-stigma interactions suggest that sporophytic incompatibility exists in wild Corylus species and that a large number of S-alleles is involved. Several interspecific crosses were compatible yet failed to set nuts in the field, indicating the presence of other barriers in these combinations. Controlled self-pollinations in the field gave low set in representatives of C. americana and C. sieboldiana, but one of four C. californica and two of three C. colurna selections set well. The apparent self-compatibility of these selections deserves further investigation.
In northwestern Italy, hazelnut yield losses and kernel defects are increasing. Early fruit drop and defects like blanks, shriveled or spotted kernels are usually attributed to insect feeding. Previous research has shown that the pests most commonly found were bugs, in particular Gonocerus acuteangulatus and Palomena prasina. The aim of this research was to determine if both species cause early nut drop, and which defects are due to bug feeding on developing nuts. The trials were performed in a nut orchard at Cravanzana (Cuneo province) during 1997-1998. In early spring, six hazelnut trees sprayed with insecticides were singly isolated in net cages. After one month, bugs were introduced into the cages as follows: G. acuteangulatus in two cages, P. prasina in another two, and no insects in the last two. To assess the influence of the cages on yield, two non-isolated trees were checked. Dropped nuts were collected every week in June and July and then examined. At harvest, the nuts of the eight trees were harvested and nut samples were observed for damage. In both years, independent of insect introduction, the quantity of early nut drop was similar in the caged plants but higher in the uncaged plants. However, this drop did not influence the yield. At harvest, spotted kernels were observed in the cages with bugs but not in those without insects, and we therefore conclude that this damage was due to bug stings. The frequency of injured kernels varied from 0.7 to 1.0% with G. acuteangulatus, and from 1.3 to 4.0 % with P. prasina.
Members of the Miridae (Lygus lineolaris Palisot de Beauvois and Pseudatomoscelis seriatus Reuter) and Pentatomidae (Acrosternum hilare Say, Euschistus servus (Say), Euschistus tristigmus (Say), Euschistus quadrator Rolston, Oebalus pugnax (F.), Piezodorus guildinii (Westwood), and Thyanta custator accerra McAtee) comprise a piercing-sucking insect complex that continues to plague multiple crops, including cotton. All these species have been associated with pathogen transmission. Breaching of boll carpel walls facilitates introduction of pathogens, and it is unknown whether stylets of these pests can fully penetrate carpel walls. Thus, stylet penetration estimates are needed and have been the focus of the present work. Stylet penetration estimates for L. lineolaris were significantly deeper than P. seriatus. Among the Pentatomidae, highest mean penetration was estimated for E. servus followed by A. hilare, yet A. hilare possessed a longer rostrum. Similarly, O. pugnax showed deeper penetration estimates than P. guildinii yet P. guildinii possessed a longer rostrum. Thus, rostrum length should not be equated to penetration potential. Pseudatomoscelis seriatus and L. lineolaris both infest early-season cotton, and the ranges of observed penetration indicate these insects, as well as the Pentatomidae, can breach the walls of critical pinhead squares and smaller bolls. The insects addressed herein affect a myriad of crops globally, and penetration estimates allow identification of growth stages susceptible to feeding and disease transmission.
Published by Oxford University Press on behalf of Entomological Society of America 2015. This work is written by a US Government employee and is in the public domain in the US.
Corylus heterophylla Fisch typically produces high ratio of blank nut in Northeast China. Structure changes of female flower cluster and fruit were observed and patterns of disodium fluorescein transport into ovule and funiculus from fruit stalks were studied in the year of 2010–2012. The results indicated that early ovary and ovule of hazelnut were visible on about 20 and 45 days after blooming respectively, and the sizes of two ovules within an ovary were equal prior to 55 days after blooming, then the differences in ovule size became obviously along with development of the fruit. Ovules within blank fruit had little changes in size and maintained 2.0–4.0 mm in length until harvest. However, the ovary size of blank was much closed to that of filled one during the whole fruit development stage. For filled nut, disodium fluorescein transport obstacle occurred at junction point of ovules and funiculus and led to the abortion of one ovule from 60 to 90 days after blooming, while bright fluoresce could be observed in funiculus until near harvest. For the blank fruit, fluorescein transport obstacle happened at junction point of ovules and funiculus first on 55 day after blooming, then the funiculus failed to execute the transport function from 60 to 90 days after blooming. In conclusion, transport obstacle occurred at junction point of ovules and funiculus first, and then happened in funiculus, and these phenomena were closely related with blank fruit formation in C. heterophylla Fisch.
Pollination is very important to obtain economical yield in hazelnut. The selection of pollinizer with suitable quality and quantity of pollen is an essential practice in hazelnut orchards. In this research, the effect of different pollinizers (Kalibar8, Kalibar11, Long d’Espagne and Merveille de Bollwiller) was compared on nut and kernel development and quality of four commercial hazelnut cultivars (Rond, Segorbe, Fertile de Coutard, Negret). Result showed that the percentage of pollen germination was more than 60% for all cultivars at the time of application, indicated that all studied cultivars have high viable pollen ratio and pollen germination capacities. The dichogamy type in the selected cultivars was all the same, and protandry was common. The considered cultivars had significant differences in blooming time; so that flowering time for male flowers varied from January 28 to March 05, and for female flowers ranged between February 10 and March 08. After fruit harvesting, nut and kernel traits were evaluated. The cross-pollination with the pollen of different pollinizers had significant effect on increasing values of final fruit setting, nut and kernel weight and kernel percentage, with decreasing blank nuts in all pollinated cultivars. While, self-pollination reduced values of nut and kernel traits and increased percentage of blank nuts. It was concluded that the pollen sources had xenia and metaxenia effects in hazelnut
Kernel spot proves to be a physiological trouble, resulting from the feeding of Hemiptera, particularly Nezara viridula L. As a result of such feeding the tissue of the kernel breaks down for a short distance around the puncture, resulting in a hemispherical discolored portion. This becomes bitter and imparts its bitterness to the whole kernel. Only the kernel is affected and the trouble cannot be detected until the nut is cracked. The insects can cause kernel spot only during the period when the kernel is hardening. They do not breed on pecans; only the adults feed on the nuts. Cowpeas and soybeans, being important breeding hosts, should not be used as cover crops in the orchards.
Nut samples of hazelnut (Corylus avellana L.) cultivars, selections, and seedlings were cracked and scored for frequency of good kernels and 7 types of defects. Blanks, poorly filled nuts, and moldy kernels were the most common defects. Variance components were calculated using defect counts from trees of 17 genotypes which were sampled in each of 4 years. The largest components were for among genotypes, genotype × year interaction, and between samples within trees. Year effects were large only for poorly filled nuts. The genotype × year interaction term was large for black tips, shrivels, and blanks. Variance components indicate limited genetic variability for brown stain, but moderate to large amounts for all other defects. Narrow sense heritability estimates from regression of progeny means on mid-parent values exceeded 50 % for frequency of blanks (51 %), moldy kernels (61 %), kernels with black tips (60 %), and doubles (84 %), but was low for frequency of shrivelled kernels (22 %), poorly filled nuts (25 %), and brown stain (15 %). The low heritability of poorly filled nuts appears to indicate that the frequency of poor fill in the first crop or two produced by a young seedling does not reliably predict the genotype's susceptibility to this disorder rather than a lack of additive genetic variance. Heritability was intermediate for frequency of good kernels (42 %). Phenotypic correlation coefficients indicate that nut weight, kernel percentage, fiber rating, and pellicle removal rating are, for applied breeding purposes, inherited independently of the frequency of the 7 types of defects.
The increased demographic performance of biological invaders may often depend on their escape from specifically adapted enemies. Here we report that native taxa in colonized regions may swiftly evolve to exploit such emancipated exotic species because of selection caused by invaders. A native Australian true bug has expanded it host range to include a vine imported from tropical America that has become a serious environmental weed. Based on field comparisons and historical museum specimens, we show that over the past 30–40 years, seed feeding soapberry bugs have evolved 5–10% longer mouthparts, better suited to attack the forest-invading balloon vines, which have large fruits. Laboratory experiments show that these differences are genetically based, and result in a near-doubling of the rate at which seeds are attacked. Thus a native biota that initially permits invasion may rapidly respond in ways that ultimately facilitate control.
The problem of seedless nuts, or “ blanks,” is common to the filbert wherever it is grown. To the commercial grower, it represents
a serious economic loss. The cause of blanks is unknown. Suspected causes for blanks are cytomixis during megasporogenesis,
genetic incompatibility between pollenizer and main-crop cultivars, self-pollination, aneuploidy, lack of double fertilization,
embryo abortion, seasonal variation, and cultural practice.
We analyzed the triacylglycerol and phospholipid contents of hazelnuts from early development to maturity. Both were analyzed by high-performance liquid chromatography coupled to a light scattering detector. Trioleylglycerol, linoleyl-dioleylglycerol, and palmitoyl-dioleylglycerol were the most predominant triacylglycerols throughout development. Triacylglycerols showed small variation during hazelnut development. Phosphatidylcholine, phosphatidylethanolamine, and phosphatidylinositol were the most abundant phospholipids. Traces of phosphatidic acid were also detected. The statistical analysis showed that the positive correlation among the individual phospholipid contents was significant. Phospholipid contents showed a steep decrease during hazelnut development. Triacylgycerols and phosphatidylcholine were isolated by preparative thin-layer chromatography, and their fatty acid profile was determined by gas-liquid chromatography. Triacylglycerols showed a high percentage of monounsaturated fatty acid moieties, whereas phosphatidylcholine had the highest percentage of saturated and monounsaturated fatty acid moieties. The polyunsaturated fatty acid moiety showed low percentages in the triacylglycerol and phospholipid backbone.
A unique mode of fertilization called "chalazogamy", whereby the pollen tube passes through the chalaza instead of the micropyle, is known in several species of derived genera in Casuarinaceae. In this paper we report the occurrence of chalazogamy in Gymnostoma ( G. poissonianum), the most primitive genus in the family. We also show that the pollen tube grows discontinuously from the stigma to ovules in about 3 months. At the time of pollination, the ovules have not yet formed in the ovary, and require a long time to develop. The pollen tube(s) lie in a zigzag line and are branched in the upper region of the style, and their growth is arrested there until the ovary develops further. Studies of the relevant literature further revealed discontinuous pollen-tube growth in relation to a prolonged period between pollination and fertilization, as well as chalazogamy, in Betulaceae, Juglandaceae and/or Fagaceae that are closely related to Casuarinaceae. This feature may have derived early in the evolution of Fagales.
Extracts of neem, Azadirachta indica A. Juss, negatively affected feeding and development of Clavigralla scutellaris (Westwood), a coreid pest of pigeonpea, Cajanus cajan (L.) Millspaugh. Labial dabbing, pod wall penetration, and seed damage by fifth instars were significantly reduced on beans, Phaseolus vulgaris (L.), that had been dipped in aqueous, methanolic, or hexane extracts of neem seed kernel. When fourth instars were dipped directly into aqueous extract, developmental abnormalities of the wings occurred at all levels tested and fecundity dropped to zero at concentrations above 0.3125%. The LC50 value was 3.14% (220 ppm azadirachtin) at 8 d. The scelionid wasp Gryon fulviventre (Crawford) is an important natural enemy of Clavigralla spp.; egg mortality from this parasitoid ranged from 37 to 85% during the fall cropping season. Feeding by newly emerged wasps was dramatically reduced when honey was mixed with aqueous neem suspension, but 6-d survivorship of adults did not differ significantly from that of the control. Wasp oviposition behavior was altered slightly when coreid eggs were treated with neem: the period of antennation was significantly extended, but time for drilling, oviposition, and marking was unaffected. Neem-dipped eggs were accepted for oviposition and progeny emerged successfully from these treated eggs. Exposure of already parasitized eggs to neem did not interfere with progeny emergence, longevity, or sex ratio. Thus, neem extract and egg parasitoids seem to be compatible and promising control strategies for C. scutellaris. Our results suggest that use of neem against pod-sucking bugs will not interfere with natural control provided by G. fulviventre.
Effetti dell'attività trofica delle cimici sulle nocciole in relazione al periodo di attacco
- Tavella L
- McPherson JE
Research on damage rate and type of green shieldbug (Palomena prasina L. Heteroptera: Pentatomidae) on hazelnut
- Saruhan I
Saruhan I & Tuncer C (2010) Research on damage rate and type of green
shieldbug (Palomena prasina L. Heteroptera: Pentatomidae) on hazelnut. Anadolu Tarım Bilimleri Dergisi 25: 75-83.
Impact des Punaises dans les Vergers de Noisetiers en France: Phase II, Suivi des Populations en Été
- M Calvy
Calvy M (2018) Impact des Punaises dans les Vergers de Noisetiers en
France: Phase II, Suivi des Populations en Été. Master Thesis, Bordeaux
Sciences Agro, Bordeaux, France.
Overwintering Biology of the Brown Marmorated Stink Bug, Halyomorpha halys (Hemiptera: Pentatomidae)
Ciancio J (2018) Overwintering Biology of the Brown Marmorated Stink
Bug, Halyomorpha halys (Hemiptera: Pentatomidae). MSc Thesis, The
University of Western Ontario, London, Ontario, Canada.
Impact des Punaises Dans les Vergers de Noisetiers en France: Phase I, Suivi des Populations au Printemps
Guignet J (2018) Impact des Punaises Dans les Vergers de Noisetiers en
France: Phase I, Suivi des Populations au Printemps. Master Thesis,
Université de Savoie Mont Blanc, Le Bourget du Lac, France.
Les Punaises en Vergers de Noisetiers Dans l'Ouest Français
- J Henry
Henry J (2015) Les Punaises en Vergers de Noisetiers Dans l'Ouest Français,
Master Thesis, AgroSup Dijon, Dijon, France.
Effetti dell'attività trofica delle cimici sulle nocciole in relazione al periodo di attacco
- L Tavella
- M Migliardi
- C Sonnati
- M Miaja
Tavella L, Migliardi M, Sonnati C & Miaja M (2003) Effetti dell'attività trofica delle cimici sulle nocciole in relazione al periodo di attacco.
Informatore Fitopatologico 53: 47-51.
Eco-Éthologie de la Punaise Verte des Bois, Palomena prasina L. (Hemiptera : Pentatomidae), Dans un Contexte Nucicole
- E Valentie
Valentie E (2019) Eco-Éthologie de la Punaise Verte des Bois, Palomena prasina L. (Hemiptera : Pentatomidae), Dans un Contexte Nucicole. Master
Thesis, Bordeaux Sciences Agro, Bordeaux, France.