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Comparative Life History Parameters of Three Stink Bug Pest Species
Abstract
California pistachios are threatened by several stink bug species (Hemiptera: Pentatomidae), including the native Thyanta pallidovirens (Stål) and Chlorochroa uhleri (Stål), as well as the invasive Nezara viridula (L.). In pistachio, control tactics often target specific life stages, which makes knowledge about life histories fundamental to successful IPM programs. For that purpose, life history parameters of these stink bug species were assessed. Nymphal development and survivorship at seven constant temperatures, upper and lower development thresholds, thermal constants, adult longevity and fecundity, and life table parameters were evaluated. No species completed development at 15°C or 35°C. For N. viridula, egg to adult development was fastest at 30°C, whereas for T. pallidovirens there was no significant difference between 27.5 and 30°C and C. uhleri development was similar between 25 and 30°C. Egg to adult survival was highest at 22.5°C and 27.5°C. The thermal requirements as degree-days (DD) to complete immature development were estimated to be 714.3, 370.4, and 434.8 for C. uhleri, T. pallidovirens, and N. viridula, respectively. For C. uhleri, life table calculations produced a value of 56.7 d for mean generation time (To), 24.89 for net reproductive rate (Ro) and 0.057 for the intrinsic rate of increase (r). Thyanta pallidovirens had a To of 39.9 d, a Ro of 81.10 and a r of 0.11. The results are discussed with respect to the improvement of IPM in California pistachios, and the information presented may contribute to the control of these pest species in other ecosystems.
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Using sown groundcovers as trap crops to protect a cash crop is a traditional pest management tool. Pistachio is a major crop in California's Central Valley, where high summer temperatures and little to no precipitation between May and November lead to summer dry-down of annual groundcover. Hemipteran pests that consist of 'small bugs' and 'large bugs' are a major contributor to nut damage, especially in organic production. In this 2-year field study, we tested the use of irrigated trap crop mixtures, sown between tree rows, to reduce those hemipteran pests' abundance or damage. Biweekly beat samples of the tree canopy and sweep samples of the sown groundcovers in trap crop plots and resident weedy vegetation in control plots were taken over two consecutive growing seasons. Arthropod richness and abundance were highest in the groundcover and tree canopy in the trap crop plots. Small and large bug pest populations were higher and lower, respectively, in the tree canopy in trap crop plots, indicating a mixed response of these hemipterans to the presence of the trap crops. Additionally, natural enemy populations were more abundant in the tree canopy in trap crop plots than in control plots. There was no difference in nut damage between plots with and without the trap crop. These findings suggest that populations of hemipteran pests and beneficials can be manipulated successfully with irrigated trap crops, but future studies will need to focus on doing so in a way that decreases hemipteran pistachio damage.
Almond, Prunus dulcis (Miller) D. A. Webb, is an important tree nut crop cultivated primarily in the Mediterranean climatic regions. However, the United States, specifically the state of California, is the largest producer and exporter of almond nuts in the world. At least 60 species of insect pests attack almonds worldwide. Hemipterans can be important pests in almond orchards. Some hemipteran insect pests in almonds include lace bugs, plant bugs, stink bugs, and leaffooted bugs. These pests use needle-like mouthparts to pierce and feed upon fruits or other parts of the plant, causing direct or indirect crop damage. Nonetheless, the biology, life history, and management practices for many hemipteran pests of almonds are not available in the literature or come from research of these insects on other crops and host plants. In this article, we discuss the current understanding of biology, ecology, and management of hemipteran pests of almonds and outline future research to advance the integrated pest management of these pests in almond orchard systems.
California currently produces about a quarter of the world’s pistachios. Pistachio nuts are
susceptible to feeding by stink bugs and leaffooted bugs; therefore, the invasive presence of the highly polyphagous brown marmorated stink bug, Halyomorpha halys (Stål) (Hemiptera: Pentatomidae), is a concern to California pistachio growers. We aimed to assess the potential of H. halys to cause yield loss and nut damage to pistachios, which had not yet been assessed in the field. Over two years, terminal branch ends with pistachio clusters were enclosed in organdy cages from spring to fall and exposed to either H. halys, the native stink bug Chinavia hilaris Say (Hemiptera: Pentatomidae), or leaffooted bug Leptoglossus zonatus (Dallas) (Hemiptera: Coreidae), for 4–7-day feeding periods at different times of the season. We found that H. halys adults cause more epicarp lesions (external damage) when recorded at harvest time than the native species. They did not, however, cause more kernel necrosis (internal damage) than the two native species tested, which is a more relevant damage criterion for commercial production. There were no differences among insect species for any other recorded damage criteria. We conclude that H. halys could cause similar damage as the native species but note that H. halys population densities in California are still low and future damage levels will be
dependent on this pest’s population density.
Euphydryas aurinia (Rottemburg 1775) is one of the most seriously threatened European butterflies, as it suffered a severe decline in most countries and it is today listed in the European Community Habitats and Species Directive (92/43/EEC). Although its ecology and biology have been increasingly studied during the 20th Century, the factors affecting its mortality have not been described in detail, and the role of natural enemies on its population dynamics is largely unknown.
In this paper, we present new data on predation events of P. bidens (Linnaeus, 1758) on caterpillars of Euphydryas aurinia spp. provincialis (Boisduval, 1828) in Central Italy, and discuss the stages during which predation could have a stronger impact. Our results show that II to IV instar nymphs of P. bidens attack the pre-diapause 3rd instar caterpillars when they live in a communal silken nest, while adults were found on butterfly larval webs, but never preying on caterpillars. The bugs visited a larval group more than once a day and at different times, and showed preference for cooler habitats (i.e., they were not observed on webs of warmer habitats). All together, our observations point out to the potential significant impact that gregarious nymphal instars can have on the population dynamics of E. aurinia in cooler habitats, where predator and prey coexist.
Invasive pentatomid Halyomorpha halys recently arrived to the Black Sea region and began damaging agricultural and ornamental plants. We studied the effects of day length and temperature on the pre-adult development and diapause induction in H. halys from Sochi (Russia) under laboratory conditions (20, 24, and 28 °C and several photoperiods). The pre-adult development of H. halys was noticeably faster under L:D 12:12 compared with L:D 15:9. The sum of effective temperatures required for the pre-adult development was ca. 530 and 590 degree days under these two conditions, respectively, whereas the lower developmental thresholds were similar (ca. 13.3 °C). Adults of H. halys demonstrated a typical long-day-type photoperiodic response of facultative winter adult diapause induction: Short days (photophases of 12–15 h) induced diapause in all adults, whereas long days (with photophases longer than 15 h) promoted reproduction. The photoperiodic responses of diapause induction of females and males were very similar. At 24 °C, the threshold of the response was between 15 and 16 h. At 20 °C, even under the very long-day conditions (L:D 18:6) about 50% of adults entered diapause. Field records suggest that H. halys likely produces two generations per year in Sochi. Short days might accelerate nymphal growth of the second generation in August and then induce winter diapause in adults. Phenological studies and monitoring are needed for a better understanding of the adaptation process of this invasive pest to new conditions.
The development of biological control methods for exotic invasive pest species has become more challenging during the last decade. Compared to indigenous natural enemies, species from the pest area of origin are often more efficient due to their long coevolutionary history with the pest. The import of these well‐adapted exotic species, however, has become restricted under the Nagoya Protocol on Access and Benefit Sharing, reducing the number of available biocontrol candidates. Finding new agents and ways to improve important traits for control agents (“biocontrol traits”) is therefore of crucial importance. Here, we demonstrate the potential of a surprisingly under‐rated method for improvement of biocontrol: the exploitation of intraspecific variation in biocontrol traits, for example, by selective breeding. We propose a four‐step approach to investigate the potential of this method: investigation of the amount of (a) inter‐ and (b) intraspecific variation for biocontrol traits, (c) determination of the environmental and genetic factors shaping this variation, and (d) exploitation of this variation in breeding programs. We illustrate this approach with a case study on parasitoids of Drosophila suzukii, a highly invasive pest species in Europe and North America. We review all known parasitoids of D. suzukii and find large variation among and within species in their ability to kill this fly. We then consider which genetic and environmental factors shape the interaction between D. suzukii and its parasitoids to explain this variation. Insight into the causes of variation informs us on how and to what extent candidate agents can be improved. Moreover, it aids in predicting the effectiveness of the agent upon release and provides insight into the selective forces that are limiting the adaptation of indigenous species to the new pest. We use this knowledge to give future research directions for the development of selective breeding methods for biocontrol agents.
The brown marmorated stink bug, Halyomorpha halys (Stål) (Hemiptera: Pentatomidae), is an invasive pest that has been resident in California since 2006. To better understand its seasonal phenology, we used baited traps to estimate nymph and adult population densities in midtown Sacramento, the focal area of the Northern California invasion. Adult H. halys populations were found soon after trapping began in February (2015-2016) or March (2014); the first egg masses for 2014, 2015, and 2016 were found on 5 May, 17 April, and 12 April, respectively, and the first nymphs were found 3 June, 19 May, and 9 May, respectively. There were two generations per year, with one peak in June and another in September. Summer temperatures above 36°C in July and August were associated with reduced catches in traps of both nymphs and adults. This extreme heat may have helped to form two clear nymph peaks and suppressed egg deposition. In 2016, two trap types and four lures were also compared. Trap type influenced season-long nymph captures, with fewer nymphs in double cone traps than pyramid traps. Lure type influenced season-long trap catch, with more nymphs and adults trapped with the Rescue lure than the AgBio Combo lure, Alpha Scents, or Trécé Pherocon Combo lures, although this difference was only associated with the capture of nymphs and we did not compare for longevity or seasonal variation. These data are discussed with respect to H. halys' phenology from the mid-Atlantic region.
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.
Stink bugs (Hemiptera: Pentatomidae) are an economically important group of insects that attack numerous crops in the central valley of California. Management of these pests using pheromones or biological control can be species specific, and proper identification of insect species is essential for effective management. The objective was to examine genetic variability in four species of stink bugs, which included Chinavia hilaris (Say) (= Acrosternum hilare) (Hemiptera: Pentatomidae) , Chlorochroa uhleri (Stål) (Hemiptera: Pentatomidae) , Chlorochroa sayi (Stål) (Hemiptera: Pentatomidae), and Thyanta pallidovirens (Stål) (Hemiptera: Pentatomidae) and to determine whether there may be cryptic species present. Stink bugs were collected in pistachios or on adjacent vegetation when abundant in the central valley of California. The mitochondrial DNA cytochrome oxidase I (COI) gene region (i.e., the barcode) was sequenced for each individual. Data were combined with available GenBank accessions for each species and used to construct a phylogenetic tree. Divergence between genera ranged from 11.2 to 15.7%, whereas divergence between the two Chlorochroa spp. was 4.6%. Genetic variation within Chinavia hilaris collections was up to 4.7%, which suggests the presence of a cryptic species. Genetic divergence was highest between individuals of Chinavia hilaris from the west coast and the east coast of the United States. In contrast, genetic variation within individuals of C. uhleri and Ch. sayi was less than 1%. Nine haplotypes were found for Chinavia hilaris, five for C. uhleri, three for Ch. sayi, and five for T. pallidovirens. The relevance of correct species identification and genetic diversity to stink bug management practices was discussed.
The brown marmorated stink bug, Halyomorpha halys, is an invasive pest species, first detected in Italy in 2012. Only 2 years after this first detection, increasing damage was reported in fruit orchards in the Emilia Romagna region, the first invaded area, which is one of the most important regions for the Italian and European fruit production. In the present study, life table parameters of H. halys populations were investigated in Italy under typical temperate/Mediterranean climate conditions representative of southern Europe. Our findings indicate that in Italy H. halys has two generations/year and very high reproductive rates for both generations (R
0 = 24.04 and 5.44 for the overwintering and summer generation, respectively). The huge growth rates explain why in 2015 a massive outbreak of H. halys was observed in Italy, and these rates confirm that the pest is a threat for agricultural production in southern Europe. The parameters obtained in this study are essential for the development and optimization of sustainable management strategies.
The brown marmorated stink bug, Halyomorpha halys (Stål), is a serious invasive pest in the USA. Organic growers have limited options to effectively manage this pest. Several organically approved insecticides including pyrethrins, azadirachtin, spinosad, potassium salts of fatty acids, sabadilla, extract from Burkholderia sp., and two combination products were evaluated for toxicity to H. halys nymphs and adults using laboratory bioassays and evaluated in field experiments on tomatoes and peppers using weekly applications of the highest labeled rates of the products. In submersion bioassays, high mortality (>70%) of H. halys nymphs was achieved with pyrethrins, azadirachtin, azadirachtin + pyrethrins, potassium salts + spinosad, and sabadilla alkaloids. Using the same bioassay for adult H. halys, only pyrethrins, azadirachtin + pyrethrins, and potassium salts resulted in high mortality. In bean dip bioassays, only pyrethrins resulted in moderate mortality of nymphs and high mortality of adults. In field experiments, which included weekly insecticide applications, none of the insecticides that were tested significantly reduced stink bug feeding injury (from all species) to tomatoes or peppers with the exception of one harvest date of peppers in 2014, where pyrethrins + azadirachtin had less injury than the control. Our results confirm that several organically approved insecticides may demonstrate a high level of activity on H. halys in laboratory bioassays, but when applied in the field, none of the products that we tested appear to be consistently effective at reducing stink bug injury to peppers or tomatoes.
Pistachio ( Pistacta vera L.) (‘Kerman’) fruits with fresh-appearing epicarp lesion (EL) symptoms caused by leaffooted bugs ( Leptoglossus spp.) or stinkbugs ( Thyanta pallidovirens Stal) (or both) were collected periodically, and the sites of EL or kernel necrosis (KN) symptoms were recorded. In addition, the sites of KN were determined in randomly collected pistachio samples. Fruit pericarp firmness was determined on symptomless healthy fruits on the base (stem end) and apex of fruits. The percentage of EL initiated at the fruit base increased from about 40% at the end of May to 80% at the beginning of August, suggesting a shift of feeding habits of leaffooted bugs and stinkbugs. Moreover, 60-74% of the Kn symptoms were found at the stem end and along the suture line, in areas of lower pericarp firmness and delayed lignification. Apparently, leaffooted bugs and stinkbugs can locate these softer areas even though they are not visually distinct.
Chinavia Orian is one of the most speciose Pentatominae genera and is distributed in the Afrotropical, Nearctic and Neotropical regions. In Brazil, 32 species are recordered, from which 18 are endemic; host-plant association from 18 species are known, and immatures or some life history traits for six species were already described. In this work, we provided a diagnosis and discuss data available on immatures and biology of all species of Chinavia found in Brazil, including a pictorial key to adult identification. Two new synonyms are recognized: Acrosternum (Chinavia) bellum Rolston, 1983 is a junior synonym of Chinavia nigrodorsata (Breddin, 1903), and Acrosternum (Chinavia) panizzii Frey-da-Silva & Grazia, 2001 is a junior synonym of Chinavia obstinata (Stål, 1860). Chinavia nigritarsis (Stål, 1872), formerly a synonym of Chinavia gravis (Walker, 1867), is reinstated. Color habitus ilustrations of all species are provided, the majority taken from type-material. New host-plant associations and distribution data to Chinavia species in Brazil are presented.
Life history parameters were established under controlled laboratory conditions for the green stink bug, Chinavia hilaris (Say) (= Acrosternum hilare), to improve pest control in pistachios in California. Parameters measured and calculated included survival and development at seven constant temperatures (ranging from 15 to 35 degrees C), development time, upper and lower development thresholds, thermal constants, fecundity, generation time, net reproductive rate, and intrinsic rate of increase. C. hilaris did not complete development at 15 and 35 degrees C. Within the range of 20-27.5 degrees C, development time decreased linearly with temperature; it increased again at 30 degrees C. The lower threshold was calculated by linear methods to be 12.3 degrees C, and the thermal constant was calculated to be 588 degree days. Fastest development was recorded at 27.5 degrees C, whereas greatest survival was observed at 22.5 degrees C. At 27.5 degrees C, mean fecundity was 53.5 eggs per female, mean generation time was 74.4 d, net reproductive rate was 20.09, and intrinsic rate of increase was 0.04. Use of a nonlinear model yielded estimates of 13.2, 28.4, and 33.4 degrees C, for the lower threshold, optimum temperature, and upper threshold, respectively. Results were compared with similar studies and interpreted in the light of pest management needs in pistachio. Increased emphasis on monitoring and management ofoverwintering sites and early-season migration are recommended.
"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 seasonal abundance of the three most important stink bug (Hemiptera: Pentatomidae) pests of soybean were studied weekly between 1977 and 1978 on both cultivated and uncultivated host plants by using a sweep-net. The sequence of black cherry, Prunus serotina Ehrhart, and elderberry, Sambucus canadensis L., in the study area allowed large populations of the green stink bug, Acrosternum hilare (Say), to develop before entering soybean, Glycine max (L.) Merrill. Populations of A. hilare in soybean peaked during September and early October. Fourteen other breeding hosts were identified but were considered unimportant. The control of black cherry and elderberry would drastically reduce the importance of A. hilare in soybean. Populations of the brown stink bug, Euschistus servus (Say), were sampled during the fruiting cycles of several hosts, including sowthistle, Sonchus oleraceous L., wheat, Triticum aestivale L., peppergrass, Lepidium virginicum L., vetch, Vieia spp., partridge pea, Cassia faseiculata Michaux, wild lettuce, Lactuca canadensis L., and horseweed, Erigeron canadensis L. The availability of preferred hosts throughout the season may account for comparatively low populations in soybean. Important hosts of the southern green stink bug, Nezara viridula (L.), were wild radish, Raphanus raphinistrum L., and wheat in spring; soybean, cowpea, Vigna unguiculata (L.) Walpers, and showy crotalaria, Crotalaria spectabilis Roth, during summer and fall. Coffee senna,Cassia occidentalis L., was highly attractive to adults of both Acrosternum hilare and Nezara viridula. Several hosts of Thyanta accerra McAtee, T. calceata (Say), and Euschistus tristigmus (Say) were also identified. Mark-recapture studies showed that adult populations of Acrosternum hilare on black cherry and Euschistus servus on mullein, Verbascum thapsus L., frequently move among individual plants.
Reproductive behavior of the stink bug Thyanta pallidovirens (Stål) was studied in the laboratory, including the determination of the sexual maturation period for both sexes, the effects of the number of copulations on fecundity, and the function of prolonged copulation. Mean premating periods for males and females were 3.6 ± 0.5 and 4.1 ± 0.6 d, respectively. Preoviposition period averaged 6.6 ± 0.9 d. Females preferred sheltered, roughtextured oviposition sites. Paired adults mated ≍13 times on average during their lifespan under laboratory conditions. The mean duration of copulations involving virgin females was >17 h, significantly longer than that of subsequent copulations, which lasted between 6.9 and 8.3 h. Multiple matings significantly increased female fecundity. Virgin males donated ≍17% of their body mass to a virgin female during mating. Duration of mating may be regulated by space available in the spermatheca for ejaculatory material. There was strong evidence of male mate choice, with males terminating copulation with small females before sperm was transferred. There was no indication of male mate-guarding behavior after copulation. Females almost always approached males from distances of >30 cm, suggesting that males attract females from a distance. Within 15 cm, males discern and approach females. Courtship behaviors of males included antennation of female antennae and abdomens, stroking the abdomens with the hind legs, and periodic male abdominal vibrations. Possible functions of these behaviors are discussed.
Development times from second-instar nymphs to adult for the southern green stink bug, Nezara viridula (L.), reared on a standard green bean (Phaseolus vulgaris L.) plus peanut, Arachis hypogaea (L.), diet were not significantly different from those reared on the meridic Debolt diet, and modifications thereof. When nymphs were reared on green beans plus peanuts and switched to the meridic diet as adults, female longevity and fecundity were significantly reduced. None of the dusky stink bugs, Euschistus tristigmus (Say); rice stink bugs, Oebalus pugnax (F.); or Banasa dimidiata (Say) reached adult stage when reared on the meridic diet. The green stink bug, Acrosternum hilare (Say); the redshouldered stink bug (Thyanta accerra McAtee); the brown stink bug, E. servus (Say); and E. quadrator Rolston were reared from egg to egg on the meridic diet. E. quadrator was successfully reared through three consecutive generations on the meridic diet.
Two novel and simple mathematical models of arthropod temperature-dependent development are proposed. These models are easy to use and have 3 (equation 1) and 4 (equation 2) ecologically meaningful parameters, respectively. Each parameter can be estimated using nonlinear regression. These models were used to compare developmental rates at constant temperatures for our own experiments on Lobesia botrana (Dennis & Schiffermuller) and for data from 6 insect species described (a total of 13 stages). In all cases, we obtained an accurate nonlinear description of the rate of development against temperature given by the adjusted R 2 (Kvalseth, 1985). The adjusted R 2 calculated extended from 0.86 to 0.99 and were identical for our equations 1 and 2. In all cases, equation 2 provided the lowest residual sums of squares. The models gave upper T L and lower T 0 temperature threshold estimations, and the estimations obtained were better by using equation 1 rather equation 2. Confidence intervals for each parameter were given and a comparison between estimated and observed temperature thresholds were presented.
The susceptibility of the stink bug species Nezara viridula (L.), Nezara antennata Scott, Piezodorus hybneri (Gmelin), and Riptortus pedestris (F.) to insecticides was tested, establishing their 50% lethal dose (LD50) values as baseline data. Third instars and adults of the four species were treated by topical application with seven insecticides: fenitrothion, fenthion, etofenprox, silafluofen, dinotefuran, clothianidin, and ethiprole. The weight of the stink bug and weight of the insecticide applied to each bug were used as explanatory variables in the probit regression analysis. The effect of the body weight on the dose-response relationship, the proportional model, was not uniform among the tested insecticide-stink bug combinations. However, the basic model fit all combinations and could estimate LD50 values successfully. Therefore, LD50 values at the medium (average) weight estimated by the basic model were selected to describe the susceptibility of the stink bugs. The LD50 value of silafluofen for N. viridula adults, and that of silafluofen and etofenprox for N. antennata adults, was at least 2,338 ng greater than the other species exposed to each insecticide. Almost all of the LD50 values for adults were over 10 times greater than those of the same species' nymphs treated with the same insecticide. Thus monitoring of occurring species and their developmental stages is important for controlling effectively the stink bug pest complex by insecticides, especially by silafluofen or etofenprox. The estimated LD50 values can be used as baseline data to compare the susceptibility of the species collected in another year or location.
The effect of simulated climate change on Nezara viridula was studied close to the species' northern range limit in Japan. Insects from the same egg masses were reared for 15 months in 10 consecutive series under quasi-natural (i.e. outdoor) conditions and in a transparent incubator, in which climate warming was simulated by adding 2.5 °C to the outdoor temperature. The warming strongly affected all life-history and phenological parameters. In the spring, the simulated warming advanced the timing of postdiapause body colour changes and reproduction. In the early summer, it increased egg production and accelerated nymphal development. In the late summer (the hottest season), the effect of the simulated warming was strongly deleterious: nymphs developed slowly, suffered higher mortality and had difficulties during final moulting; the emerged females were smaller, some exhibited abnormal cuticle, produced fewer eggs and had a decreased life span. In the autumn, the warming accelerated nymphal development, resulted in larger female size, affected the timing of the diapause-associated adult body colour change from green to russet and enhanced preparation for overwintering. Larger females had higher winter survival rate than smaller females. The warming strongly increased survival rate in both size classes and allowed smaller females to reach the same winter survival rate as larger females had under the quasi-natural conditions. The winter survival also differed between the green and dark-coloured females under the quasi-natural, but not under the warming conditions. However, under the warming conditions, green females survived the winter even better than dark-coloured females did under the quasi-natural conditions. The warming also shortened the life span of females from the summer generations and prolonged it in those from the autumn generation. It is concluded that even a moderate temperature increase (+2.5 °C) in the future is likely to have a complex influence upon insects, strongly affecting many of their life-history and phenological parameters.
Polymorphism in adult colour pattern ofNezara viridula is determined on the genetic basis. The basic colour patterns of adult are classified into four types, i. e. G, O, R and F. No appreciable differences between these types were observed in respect to various physiological traits of nymphs and adults, except that type G seems to be superior in reproductive ability but to be inferior in ability of surviving winters at least to types R and F.
Inter-generation changes in percentage frequency of G type were examined from 1959 to 1967 covering more than 30 generations. Percentage frequencies of G types prior to the severe winter of 1962–3 fluctuated greatly around a mean of 87.9%, while they did to a lesser extent than before with a mean of 85.0% after the winter. Unexpected high percentages of G type were recorded frequently in summer generations, viz. 1st and 2nd. On the other hand, the relative frequencies of G and O types decreased after hibernation in contrast to the increases in those of F and R. This sort of changes in genetic composition related to the winter of 1962–3 was observed in several populations segregated from each other.
This seasonal alternation of selective activity in the environments is considered to be responsible for retention of the polymorphism. Alternative possible causes, i. e. difference in habitat preference, non-random mating and selective predation by predators among polymorphs, may safely be rejected as irrelevant to the mechanism in maintaining polymorphism.
The polymorphism of this insect seems to be in a transient state rather than balanced one contributing little to population regulation, but the persistence ofN. viridula in the periphery range may be assisted by retention of the polymorphism.
Field and laboratory studies were conducted with the Neotropical red-shouldered stink bug Thyanta perditor (F.) (Heteroptera: Pentatomidae) aiming to evaluate parasitism incidence on adults by tachinid flies (Diptera: Tachinidae), which were raised in the laboratory for identification. Egg deposition by flies on adult body surface was mapped. In addition, nymph and adult incidence on the wild host plant black jack, Bidens pilosa L. (Asteraceae), during the vegetative and the reproductive periods of plant development was studied. Seven species of tachinid flies were obtained: Euthera barbiellini Bezzi (73% of the total) and Trichopoda cf. pictipennis Bigot (16.7%) were the most abundant; the remaining five species, Gymnoclytia sp.; Phasia sp.; Strongygaster sp.; Cylindromyia cf. dorsalis (Wiedemann); and Ectophasiopsis ypiranga Dios & Nihei added 10.3% of the total. Tachinid flies parasitism on T. perditor adults was significantly greater on the dorsal compared to the ventral body surface. On the dorsal surface, the pronotum was significantly preferred and the wings the least preferred site. No differences were observed on the number of tachinid fly eggs deposited on wings, considering the “under” and “above” sites. Results indicated a significantly greater number of nymphs on mature compared to immature seeds. Adults significantly preferred immature compared to mature seeds; both were less abundant on leaves/stems and inflorescences.
Many scientists have reported an extensive amount of information on the biology, life history, and damage potential of stink bugs. However, this information is scattered among numerous journals, periodicals, and other publications. Stink Bugs of Economic Importance in America North of Mexico brings together the applied and nonapplied literature in one complete and concise format. The book gives you: • Section by section discussions of various economic stink bug species and damage to individual crops • Separate tables of host plants organized by common name, scientific name, and family name • General biology for each economic stink bug species Strategies for the control of destructive species • Keys for identification of stink bug species • Numerous unique line drawings • Over 700 references on stink bug publications Written by two top-notch researchers whose experience is complementary, the book examines these constant pests. The first comprehensive resource on this fascinating and destructive group of insects, Stink Bugs of Economic Importance in America North of Mexico provides you with a reference that you can use in the laboratory or in the field for easy identification of pentatomids.
Among environmental factors, temperature has a direct and crucial influence on the key life processes of survival, development, reproduction, and movement of poikilothermic animals and hence their population dynamics. The lower and upper temperature thresholds and optimal temperature have ramifications for all major life processes, where within a specific range, a temperature change results in a proportional rise or fall of the rate of any given process. There are some basic approaches for modeling development response to temperature in arthropods. The oldest and most widely used model is a simple linear description of arthropod development in relation to temperature. The linear model forms the basis of the well-known thermal summation or degree-day (DD) approach to timing prediction. The second approach for predicting arthropod development rate is nonlinear mathematical models. However, given the fundamental role of thermal models in forecasting and integrated pest management programs, the main purpose of this paper was to facilitate the use of thermal models to estimate the developmental response of arthropods to temperature and select the appropriate model with a view to goodness-of-fit and generalizability by designing a user-friendly software. In this paper, the linear and most common nonlinear thermal models and the main criteria for selecting appropriate models are also reviewed.
Panicle and shoot blight of pistachio caused by species of Botryosphaeriaceae fungi remains one of the major diseases of pistachio in California, with the highest potential for crop destruction because buds and fruit clusters (panicles) are killed. Pistachio fruit can also be damaged by various insect pests. For instance, hemipteran insects are considered major pests of pistachio and can attack maturing fruit, causing necrotic areas on the fruit epicarp (epicarp lesion). Surveys in pistachio orchards showed a putative association of punctures of pistachio fruit with infection by Botryosphaeriaceae fungi, resulting in panicle and shoot blight. This study was undertaken to determine any association of Botryosphaeriaceae fungi with fruit bearing epicarp lesions and whether hemipteran insects can actively carry propagules of the pathogens to healthy fruit and cause disease. Three large insects of the order Hemiptera (Thyanta pallidovirens, Acrosternum hilare, and Leptoglossus clypealis) were used in pathogen-spread and infection experiments. The most frequently isolated species of the family Botryosphaeriaceae in pistachio, Neofusicoccum mediterraneum, was used in these transmission experiments. Significantly higher incidence of fruit infected by N. mediterraneum was recorded when pistachio clusters were sprayed with a spore suspension of N. mediterraneum and caged with the above insects than the level of infected fruit sprayed similarly with the pathogen but caged without any insects. Furthermore, increasing the number of insects caged with pistachio clusters resulted in an increase of insect feeding punctures and, subsequently, disease incidence. Similarly, increasing the number of wounds per fruit made with a needle, simulating injuries caused by the insect's stylet, resulted in significantly higher incidence of infected fruit than for wounded fruit with fewer injured sites. In addition, bird injured fruit were also associated with higher incidence of panicle blight than fruit not injured by birds, especially in orchards with high disease incidence. In laboratory experiments, wounding or applying fruit sap to nonwounded fruit resulted in significantly higher incidence of infected fruit than in nonwounded fruit without sap. In field experiments, wounding of fruit before or after inoculation with N. mediterraneum resulted in higher disease incidence than nonwounded and inoculated fruit. Additionally, fruit sap enhanced initial mycelial growth of N. mediterraneum. Protecting fruit clusters from injuries by hemipteran insects or birds using mesh cages significantly reduced the incidence of panicle and shoot blight. The association of wounding by hemipteran insects and birds with high incidence of infected pistachio fruit may explain partially the broad distribution of Botryosphaeria panicle and shoot blight among pistachio orchards of the central San Joaquin Valley, even in areas where inoculum sources are not nearby.
Effects of temperature on the development and the mortality of the southern green stink bug, Nezara viridula and the oriental green stink bug, N. antennata were studied under a series of constant temperature. Relation between rearing temperature and the colouration of the 4th and 5th instar nymphs in both species was also observed. 1) The relation of rearing temperature and the development in both species can be expressed by straight line, if reciprocals of incubation period and larval period, i.e., the developmental velocities are plotted against temperature. 2) In both N. viridula and N. antennata, the developmental zero and the total effective temperature are obtained as follows: [formula omitted] 3) Within a temperature range used in this experiment, the zone of favourable temperature for development from egg to the emergence of imago seems to lie between 20 and 30°C in N. viridula and between 22.5 and 27.5°C in N. antennata. The optimum temperature for development is near 30°C in the former species and near 27.5°C in the latter. 4) In both species, individuals bearing melanic pattern occur more frequently with the fall of temperature (Figs. 3 and 4), indicating that temperature can be regarded as the main factor responsible for the variation of the body colour of the 4th and 5th instar larvae. © 1961, JAPANESE SOCIETY OF APPLIED ENTOMOLOGY AND ZOOLOGY. All rights reserved.
A transition matrix model is developed for changes in the abundance of a population of Panonychus ulmi, the European red mite, in a managed apple orchard. Thee population is divided into two age classes, eggs and motile mites. This is a single-species model that considers transitions among four states (defined in terms of high/low egg and mite abundance on a tree) over two summer seasons. Transition probabilities vary through time as functions of temperature and mite abundance. The effects of miticide application are incorporated. The model provides an excellent fit to the data and is capable of predicting abundance changes in a second orchard. There is a strong tendency for the population to attain high abundance, especially given moderate early season abundance and warm temperatures. The model can indicate likely outbreaks of this commercially important pest species.
There were noticeable differences in the rate of development, survival rate and diapause incidence among Nezara viridula L. individuals reared at different temperatures and photo-periods. The optimum temperature for the greatest rate of development and survival of immature stages was 25° C. Long and short photoperiods, influenced the rate of development at 20° C and 25° C, however, this effect completely disappeared at 30° C.At 25° C, photoperiods of 10 and 11 hours per day induced diapause in large percentage of adults; intermediate photoperiod of 12 hours per day induced 28.6 % diapause while long photoperiod of 14 hours per day supressed the induction of diapause. The critical photoperiod is approximately 12 hours light per day. The stage or stages sensitive to photoperiod inducing diapause, or conversely initiating maturation of gonads was determined to be the fourth nymphal stage. The present paper deals with informations about rate of development, daily rate of increase in adult body weight, diapause incidence and maturation of gonads as influenced by different temperature and photoperiods conditions.ZusammenfassungPhotoperiode und Temperaturwirkungen auf die Entwicklungsrate und Diapause von Nezara viridula L. (Heteroptera: Pentatomidae)Bei Aufzucht von N. viridula unter verschiedenen Temperaturen und Photoperioden kam es zu erheblichen Unterschieden in der Entwicklungsrate, überlebensrate und dem Auftreten der Diapause. Das Optimum für die größte Entwicklung und überlebensrate der präadulten Stadien war 25° C. Lange und kurze Photoperioden beeinflußten die Entwicklungsrate bei 20° und 25° C, aber nicht bei 30° C.Unter 25° C induzierten Photoperioden von 10 und 11 Stunden täglich bei einem großen Prozentsatz der Adulten eine Diapause. Eine mittlere Photoperiode von 12 Stunden führte bei 28,6 % der Tiere zur Diapause, während eine längere Periode von 14 Stunden die Diapause verhinderte. Somit bildet eine Photoperiode von 12 Stunden die kritische Diapause-Grenze. Als das (für die von der Photoperiode induzierte) diapause-empfindlichste Stadium, in welchem durch die Diapause die Gonadenreifung sistiert wird, wurde das 4. Larvenstadium festgestellt.Die vorliegende Arbeit gibt Informationen über die Entwicklungsrate, die tägliche Rate der Gewichtszunahme der Adulten, das Eintreten der Diapause und die Reifung der Gonaden unter dem Einfluß verschiedener Temperatur- und Photoperiode-Verhältnisse.
Background
Codling moth, Cydia pomonella (L.) (Lepidoptera: Tortricidae), is a major pest of apple, pear and walnut production in North America. Management programs are based on preventing larval entry into the fruit or nut and are typically timed by heat-driven models that are synchronized to field populations by first capture of overwintering moths in pheromone traps. Unfortunately, trap capture is affected by a range of environmental parameters as well as by the use of mating disruption, which makes detecting first flight difficult, thus complicating implementation of management programs. The present goal was to evaluate data collected from a broad range of locations across North America to see whether average first spring emergence times could be predicted. ResultsAverage emergence time on a degree-day scale from 1 January was predictable using latitude and elevation. Sites at elevations of <400m fit a simple quadratic equation using latitude, but, when higher elevations were included, a multiple regression using elevation was required. Conclusions
The present models can be used to simplify management programs for codling moth in areas where heat-driven models that require extensive trapping to synchronize with emergence are currently used. (c) 2013 Society of Chemical Industry
The cosmopolitan southern green stink bug Nezara viridula (Hemiptera: Heteroptera: Pentatomidae) is highly polyphagous on many important food and fibre crops. Comments are made on its geographical and host range; bionomics and seasonal phenologies (including life history, diapause and overwintering); aspects of behaviour (including nymphal and adult patterns of aggregation and dispersion, courtship, mating and defence); biological control (the most successful being the scelionid egg parasitoid Trissolcus basalis and the tachinid flies Tachinus pennipes and Trichopoda pilipes; and natural mortality and environmental considerations. Use of trap crops as a control strategy for management of this pest has excellent potential for reducing crop damage. -P.J.Jarvis
The effects of pea, Pisum sativum L., and lentil, Lens culinaris Medik., development on reproduction and longevity of Thyanta pallidovirens (Stal) were evaluated in the laboratory. Stink bug reproduction and longevity were both significantly affected by the host plants' developmental stage. The greatest number of eggs, with the highest number of viable eggs and eggs per clutch, were laid and the longest life span occurred on peas or lentils with mature pods. Insects given peas or lentils with flowers and immature pods had shorter life spans and produced significantly fewer total eggs, eggs per clutch, and viable eggs. Almostno eggs were produced by females given seedlings or only flowering host plants.
Various types of petroleum oil alone, methidathion or chlorpyrifos alone, and combinations of oil with the two insecticides applied as a single dilute spray at the ½-in. green growth stage were all highly effective against overwintering Quadraspidiotus perniciosus (Comstock). During the summer, handgun applications of dilute methidathion, azinphosmethyl, encapsulated methyl parathion, chlorpyrifos, diazinon, methomyl, and fenvalerate effectively prevented fruit infestation when sprays were applied against crawlers. Two applications during each generation of crawlers, one at the beginning and another 10 to 14 days later, provided the best control. In tests conducted in 1983 in the Hudson Valley when materials were applied with airblast sprayers, fruit infestation was considerably more severe in commercial orchards treated with azinphosmethyl than in those sprayed on the same schedule with encapsulated methyl parathion or chlorpyrifos. A SJS forecast model was developed to allow growers to time summer sprays against both crawler generations. Validation trials conducted in 1983 demonstrated that this forecast model was somewhat more reliable in predicting crawler emergence in New York than the Predictive Extension Timing Estimation Model and was sufficiently accurate to be used in practical management programs.
Adult stink bugs were introduced onto caged, bush-type tomatoes to establish the amount of fruit damage resulting from different durations of infestation (up to 20 d), densities (1, 3, 5, and 10 bugs per 2 m of row), species (Euschistus conspersusUhler and Chlorochroa uhleri (Stal)) and reduced fruit abundance (75,50, and 0% reduction). Factors that significantly influenced the percentage of tomato fruit damaged were stink bug density and reduced fruit density at constant stink bug densities. Stink bug density affected the number of damaged areas per fruit in 1 of the 2 years of the study. Stink bug species and the number of days of stink bug infestation did not affect the percentage of damaged fruit or the number of damaged areas per fruit. Implications for stink bug management in tomatoes grown in California are discussed.
The green stink bug, Acrosternum hilare (Say), attacks many wild and cultivated hosts. Recently it has been demonstrated to transmit Nematospora coryli Peglion, the fungus causing yeast-spot disease of soybeans (Daugherty 1967).
The influence of soybean seed protein and oil level on developmental time, weight, and survival of southern green stink bug, Nezara viridula (L.), was examined. Developmental times and weights of adults and nymphs were similar to those reported by other researchers. Diet had a small but significant effect on developmental time to second, third, and fourth instar, with consumption of higher protein (lower oil) resulting in decreased developmental time (e.g., days to fourth instar = 13.3 on high protein diet compared with 15.2 on low protein diet). However, developmental time from hatch to fifth instar and adult was not significantly affected by diet. Maximum differences between diets at any life stage were only 2 d. Males and females had similar developmental times. Increasing seed protein resulted in greater adult weights of both males and females (e.g., weight of females = 182.2 mg on high protein diet compared with 153.0 mg on low protein diet) but had no effect on weights of nymphs. Females were significantly heavier than males from fourth instar to adult. Stink bug genotype (blocks) significantly affected developmental time and weight of all nymphal instars and adults. Survival was not affected by diet or stink bug genotype.
The biology and seasonal phenology of Caloeoris norvegieus (Gmelin) were studied in pistachios, Pistaeia vera L., and associated host plants in the laboratory and four orchards in the Sacramento Valley. Nymphs were found in weeds in the orchards from late March; adults were found in early April and disappeared by late May. In beating-tray samples, adults were observed on pistachio clusters from 12 April until 25 May. Increases in numbers of adults in the beating-tray samples corresponded to high levels of epicarp lesion, ranging from 11 to 34%. Dispersal to pistachios coincided with the development of adults and was correlated with the drying of orchard weeds or cutting of alfalfa. C. norvegicus nymphs and adults were recorded on various host plants, which included several species of legumes, mustards, and orchard grasses. In late March, first instars hatched from diapausing eggs laid in the dried stems of wild radish, Raphanus sativus L., and wheat, Triticum aestivum L. Neither eggs nor first instars were found on pistachio limbs. In the laboratory, survival ~ adulthood was 92-98% on winter vetch, View vil/osa Roth, curly dock, Rumex erispus L., and wild radish, and 25% in wild oats, Avena fatua L. Oviposition was observed within all herbaceous hosts except wild oats.
Two insecticides (carbaryl and permethrin) failed to control epicarp lesion (EL) in a pistachio orchard at Winters, Calif., because several hemipterous insect species continually invaded the orchard. Beating-tray and sweep-net samples revealed high adult populations of Psallus vaccinicola (Knight), Psallus ancorifer (Feiber), and Liorhyssus hyalinus (F.). Nymphs and adults of a Neurocolpus sp., Calocoris norvegicus (Gmelin), Thyanta pallidovirens (Stål),Lygus hesperus (Knight), and Leptoglossus clypealis (Heidemann) also were collected. A Phytocoris sp. (Miridae) was captured in a sticky trap placed in the orchard. Psallus vaccinicola, Neurocolpus sp., C. norvegicus, Phytocoris sp., and the rhopalid L. hyalinus induced EL on young pistachio fruits from early April to late May, while the pericarp firmness was ≤1.8 kg force. In contrast, nymphs and adults of T. pallidovirens and L. clypealis were able to cause EL until late June (pericarp firmness, 4.0 kg force), and kernel necrosis (KN) thereafter (pericarp firmness, 5.5-6.0 kg force). All insect species appeared to prefer feeding in or near the base of the fruit, which lignified later than the fruit apex. Also, significantly less KN (19-34%) developed in clusters protected with net bags compared with uncaged controls (48-65% KN).
Effect of temperature on developmental duration and demographic parameters of Tetranychus urticae Koch and Eotetranychus carpini borealis (Ewing) were investigated at five constant temperatures. Immature development for T. urticae was shorter than that of E. carpini borealis. A major difference in developmental time and fecundity rates between the two species was observed at 30°C, where T. urticae had the shortest developmental time and highest daily fecundity compared with E. carpini borealis. Developmental times for the two spider mite species fell within the range of developmental times reported for other spider mites. Life tables were constructed for both species. The intrinsic rate of increase for T. urticae ranged from 0.08 at 15°C to 0.321 at 30°C, whereas that for E. carpini borealis ranged from 0.065 at 15°C to 0.151 at 30°C. Temperature-development data were fitted to a nonlinear model. This model allowed the detection of some basic differences between the two spider mite species. In addition, simple linear regression was used to estimate lower developmental thresholds and degree-day requirements for development. Those data were in agreement with field observations.
Development and survival of melon fly, Bactrocera cucurbitae (Coquillett), oriental fruit fly, B. dorsalis (Hendel), B. latifrons (Hendel), and Mediterranean fruit fly, Ceratitis capitata (Wiedemann) eggs, larvae, and pupae were compared at 5 constant temperatures ranging from 16 to 32°C. Durations of the immature stages of B. cucurbitae, C. capitata, B. dorsalis, and B. latifrons ranged from 12.9 to 40, 14.7 to 46.2, 15.4 to 47.1, and 18.2 to 61.6 d, respectively, at 32-16°C. Species differed most conspicuously in duration of the egg stage and least conspicuously in duration of the pupal stage. Survivorship data indicated that B. latifrons was adapted to a narrower range of temperatures than the other 3 fruit fly species. Developmental thresholds were lower for the larval stage than for the egg and pupal stages for all species. Threshold values for all stages of C. capitata were lower than those for all Bactrocera species. Thermal requirements (degree-days) for development in the pupal stage were gr
We investigated the effects of weed hosts on stink bug density and damage (Euschistus conspersus Uhler and Thyanta pallidovirens Stal), and a nectar bearing plant on natural enemies of stink bugs in the Sacramento Valley of California. Stink bug density and fruit damage were evaluated in processing tomatoes adjacent to weedy and cultivated borders. The density of E. conspersus was significantly greater in tomatoes adjacent to weedy borders in July but not during August/September. Thyanta pallidovirens was less abundant overall (19%), but was found in significantly greater densities adjacent to cultivated borders in July but not in August/September. Mean percent fruit damage by stink bugs was greater adjacent to the weedy border than the cultivated border, but this difference was not significant. Stink bug egg parasitism and generalist predator density were evaluated in fresh market tomatoes adjacent to a sweet alyssum (Lobularia maritima L.) border and an unplanted control border at three sites. Egg parasitism was significantly greater in the alyssum treatment for the 9–12 September sampling period. Jalysus wickhami VanDuzee (Hemiptera: Berytidae) density was significantly greater in the alyssum treatment in mid-June. No other significant differences in predator populations were detected. Results of these two studies show that habitat manipulations have the potential to reduce densities of E. conspersus in tomato, the first step in developing a farmscape management plan for stink bug control.
Field studies of inoculative releases of Trissolcus basalis (Wollaston) (Hymenoptera: Scelionidae) in early-maturing soybean, used as a trap crop, were conducted during four consecutive seasons to evaluate the parasitoid's potential as an IPM tactic for use against stink bug (Pentatomidae) species. Fifteen thousand adults of the parasitoid were released per hectare in the trap crop when the first stink bugs were detected in the experimental area. The stink bug population density was reduced by an average of 54% in the trap crop and by 58% in the main crop. The inoculative releases produced a reduction and delay in the stink bug population peak, mainly represented by Nezara viridula (L.), Piezodorus guildinii (Westwood) and Euschistus heros (Fabr.), which were held below economic threshold levels during the most critical stages of stink bug attack on soybean (pod and seed fill, R3–R6). As a result, seed quality was better in areas where T. basalis was released, demonstrating the efficacy of inoculative releases of this egg-parasitoid which could be an important component of the soybean IPM program in Brazil.
This concluding survey of the problems considered in the Symposium naturally falls into three sections. In the first brief
section certain of the areas in which there is considerable difference in outlook are discussed with a view to ascertaining
the nature of the differences in the points of view of workers in different parts of the field; no aspect of the Symposium
has been more important than the reduction of areas of dispute. In the second section a rather detailed analysis of one particular
problem is given, partly because the question, namely, the nature of the ecological niche and the validity of the principles
of niche specificity has raised and continues to raise difficulties, and partly because discussion of this problem gives an
opportunity to refer to new work of potential importance not otherwise considered in the Symposium. The third section deals
with possible directions for future research.