Hans-Michael Poehling

Leibniz Universität Hannover · Institute of Plant Diseases and Plant Protection

Manipulating phytophagous insects with light-based repelling techniques has shown its potential to be a useful tool in integrated pest management systems in the future. Underlying optical mechanisms can be applied in field and in protected cultivation, with reflecting materials or emitting light sources, such as LEDs. Many pest insects are characte...

Reducing initial aphid infestation by use of coloured mulch foils and newly developed biodegradable spray-films Reduzierung des Initialbefalls durch Aphiden unter Nutzung von gefärbten Mulchfolien und neu entwickelten bioabbaubaren Sprühfilmen Affiliation 1 Abstract A newly invented biodegradable sprayable film based on renewable raw materials was...

Whiteflies are major pests on several vegetable and ornamental crops. Landing behaviour is strongly influenced by wavelength (nm) of reflected light from ground and surrounding vegetation. This paper deals with manipulation of whitefly landing behaviour in semi-field greenhouse experiments using background foils, either white foils with high reflec...

Shade effects on coffee diseases are ambiguous because they vary depending on the season and environment. Using Coffee Leaf Rust (CLR) as an example, we demonstrate relationships between the environment and shading systems and their effects on disease intensity. We characterized seasonal variations in microclimate and CLR incidence across different...

Visual orientation in the greenhouse whitefly (Trialeurodes vaporariorum Westwood, Hemiptera: Aleyrodidae) is the result of “wavelength‐specific behaviours.” Green–yellow elicits “settling behaviour” while ultraviolet (UV) radiation initiates “migratory behaviour.” The only available physiological study of the photoreceptors' spectral efficiency sh...

In agricultural ecosystems, insect pests, pathogens, weather patterns, and reduced soil fertility pose major challenges to crop productivity and are responsible for significant yield losses worldwide. Iris yellow spot virus (IYSV) vectored by Thrips tabaci Lindeman, is a major hindrance to onion production in eastern Africa. Control measures often...

Pest monitoring is an important tool for successful integrated pest management programmes. Blue sticky traps are important for monitoring western flower thrips, Frankliniella occidentalis, in greenhouses. However, blue sticky traps have three major weak points: (1) efficacy depends on reflection of light, which varies in intensity with fluctuating...

The short-range diurnal dispersal pattern of adult western flower thrips Frankliniella occidentalis (Pergande), in relation to spatial distribution of French beans, was determined in the field. A total of 1200 adult female F. occidentalis were released on 60 French bean plants with 20 adult thrips per plant at the central release point of 3.14 m ²...

Herbivorous insects frequently share host plants and require similar abiotic conditions. Therefore, they often occur simultaneously in crops. Tomato plants express intrinsic and induced defence mechanisms against a variety of herbivorous insects like aphids. Factors associated with the aphids’ sucking activity can affect subsequent herbivores direc...

Tomato spotted wilt virus (TSWV) is mainly vectored by Frankliniella occidentalis Pergande, and it potentially activates the vector's immune response. However, molecular background of the altered immune response is not clearly understood. Therefore, using a proteomic approach, we investigated the immune pathways that are activated in F. occidentali...

This study evaluated the efficacy of the foliage-dwelling predator Orius laevigatus, soil applied entomopathogens and azadirachtin alone and in combinations for controlling western flower thrips (WFT). Evaluated products were Nemastar®Steinernema carpocapsae (E-nema) and O. laevigatus (Re-natur), Metarhizium anisopliae isolate ICIPE-69 and NeemAzal...

Light of different wavelengths affects various physiological processes in plants. Short-wavelength radiation (like UV) can activate defense pathways in plants and enhance the biosynthesis of secondary metabolites (such as flavonoids and glucosinolates) responsible for resistance against certain herbivorous insects. The intensity of light-induced, m...

The complexity of tospovirus–vector–host plant interaction is linked to a range of factors influencing vector's efficacy in virus transmission, leading to high variability in the transmission efficiency within vector populations. Main shortcomings of most studies are the missing information on the intrinsic potential of individual insects to serve...

Earlier studies have shown that Tomato spotted wilt virus (TSWV) influences the biology, performance, and behavioral patterns of its vector Frankliniella occidentalis Pergande. In this study, using Capsicum annuum L. as the host plant, we aimed to determine the manipulation of F. occidentalis by TSWV through switching of the diet (+ or −TSWV) durin...

The scientific community has recognized the importance of integrating farmer’s perceptions and knowledge (FPK) for the development of sustainable pest and disease management strategies. However, the knowledge gap between indigenous and scientific knowledge still contributes to misidentification of plant health constraints and poor adoption of manag...

Participatory Rural Appraisal (PRA) tools. (PDF)

Expert discussion notes. (TXT)

Although short-wavelength light and especially UV radiation can induce resistance in plants against herbivorous insects, the optimal wavelengths, light intensities (photon flux rates), and illumination schedules for inducing resistance have not been previously determined. Light-emitting diode (LED) illumination enables researchers to subject insect...

Several models have been studied on predictive epidemics of arthropod vectored plant viruses in an attempt to bring understanding to the complex but specific relationship between the three cornered pathosystem (virus, vector and host plant), as well as their interactions with the environment. A large body of studies mainly focuses on weather based...

Several models have been studied on predictive epidemics of arthropod vectored plant viruses in an attempt to bring understanding to the complex but specific relationship between the three cornered pathosystem (virus, vector and host plant), as well as their interactions with the environment. A large body of studies mainly focuses on weather based...

The tospovirus-plant-vector interaction is a specific and complex relationship. It is established that several factors influence this interaction leading to high variability of transmission efficiency of the virus within a vector population. We studied the contribution of vector gender to this interaction using Frankliniella occidentalis (western f...

The tospovirus-plant-vector interaction is a specific and complex relationship. It is established that several factors influence this interaction leading to high variability of transmission efficiency of the virus within a vector population. We studied the contribution of vector gender to this interaction using Frankliniella occidentalis (western f...

Neem products have been used frequently as an alternative to synthetic pesticides, because of their insecticidal, insect antifeedant, and growth-regulating effects. Moreover, new formulations are continually being developed and therefore, they have to be evaluated for their efficacy and persistence. In this regard, two soil-applied products—a liqui...

Performance of soil application of azadirachtin products with entomopathogens was evaluated as single treatments, in multiple combinations and in different concentrations against the soil stages of western flower thrips, Frankliniella occidentalis (Pergande), in French beans Phaseolus vulgaris L. Treatments consisted of NeemAzal-T solution, neem pe...

Western flower thrips (WFT), Frankliniella occidentalis (Pergande), is an important pest of vegetable crops worldwide and has developed resistance to many insecticides. The predatory mites Neoseiulus (=Amblyseius) cucumeris (Oudemans), the entomopathogenic fungus Metarhizium anisopliae (Metsch.) and an insecticide (imidacloprid) were tested for the...

Abstract: Western flower thrips (WFT), Frankliniella occidentalis (Pergande), is an important pest of vegetable crops worldwide and has developed resistance to many insecticides. The predatory mites Neoseiulus (=Amblyseius) cucumeris (Oudemans), the entomopathogenic fungus Metarhizium anisopliae (Metsch.), and an insecticide (imidacloprid) were tes...

Endophytic fungi colonize healthy plant tissues and can in some cases induce systemic resistance to the host against biotic and abiotic stresses. In our previous study, Hypocrea lixii isolate F3ST1 was able to colonize onion plants endophytically and conferred resistance to them against onion thrips, Thrips tabaci. To further elucidate the mechanis...

Western flower thrips (WFT), Frankliniella occidentalis (Pergande), is an important pest of vegetable crops worldwide and has developed resistance to many insecticides. The predatory mites Neoseiulus (=Amblyseius) cucumeris (Oudemans), the entomopathogenic fungus Metarhizium anisopliae (Metsch.), and an insecticide (imidacloprid) were tested for th...

Coffee berries are known to release several volatile organic compounds, among which is the spiroacetal, conophthorin, an attractant for the coffee berry borer Hypothenemus hampei. Elucidating the effects of other spiroacetals released by coffee berries is critical to understanding their chemo-ecological roles in the host discrimination and coloniza...

Visual traps like yellow sticky card traps are used for monitoring and control of the greenhouse whitefly (Trialeurodes vaporariorum). However, reflected intensity (brightness) and hence, attractiveness depend on the ambient light conditions, and the colour (wavelength) might not fit with the sensitivity of whitefly photoreceptors. The use of light...

Endophytic fungi, which live within host plant tissues without causing any visible symptom of infection, are important mutualists that mediate plant-herbivore interactions. Thrips tabaci (Lindeman) is one of the key pests of onion, Allium cepa L., an economically important agricultural crop cultivated worldwide. However, information on endophyte co...

UV-radiation (UV-A and UV-B) can affect the behaviour of herbivorous insects either directly or indirectly through plant-insect interactions. Short-wavelength radiation is perceived by plants through specific receptors which results particularly in the biosynthesis of secondary plant metabolites. Known induced substances are mainly flavonoids which...

Endophytic fungi, which live within host plant tissues without causing any visible symptom of infection, are important mutualists that mediate plant-herbivore interactions. Thrips tabaci (Lindeman) is one of the key pests of onion, Allium cepa L., an economically important agricultural crop cultivated worldwide. However, information on endophyte co...

Endophytic fungi, which live within host plant tissues without causing any visible symptom of infection, are important mutualists that mediate plant-herbivore interactions. Thrips tabaci (Lindeman) is one of the key pests of onion, Allium cepa L., an economically important agricultural crop cultivated worldwide. However, information on endophyte co...

Unanswered key questions in bark beetle-plant interactions concern host finding in species attacking angiosperms in tropical zones and whether management strategies based on chemical signaling used for their conifer-attacking temperate relatives may also be applied in the tropics. We hypothesized that there should be a common link in chemical signa...

The general principles in pathogen transmission by insects involve a complex and specific interplay, in this case between thrips, tospovirus and their shared host plant, which has led to outbreaks of crop disease epidemics of economic and social importance. The possible processes and factors driving their co‐evolution were partly studied by rearing...

Use of UV-absorbing films has recently developed into a promising tool to control insect pests under greenhouse conditions. UV-absorbing films that significantly reduce transmission of UV-A and UV-B natural solar radiation can interfere with vision of herbivorous insects. The exclusion of UV from natural sunlight hampers flight initiation, dispersa...

Western flower thrips (WFT), Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), is an important pest of French beans in Kenya. However, information on the feeding activity and oviposition preference of WFT on crop and weed hosts associated with French beans in Kenya and other parts of the world is lacking. To determine the feeding and...

Visual traps like yellow sticky card traps are used for monitoring and control of the greenhouse whitefly (Trialeurodes vaporariorum). However, reflected intensity (brightness) and hence attractiveness depend on the ambient light conditions, and the color (wavelength) might not fit with the sensitivity of whitefly photoreceptors. The use of light e...

The seasonal abundance of western flower thrips (WFT) [Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae)] and its natural enemies on French beans in two agro-ecological zones (AEZs) (high and mid altitude) in Kenya, was studied in three growing cycles from January to December 2009. French beans were sampled every 2 weeks for WFT and n...

For the hoverfly Episyrphus balteatus (DeGeer 1776) which is one of the most important aphid antagonists in agricultural landscapes, annual long distance migration is supposed to be the main overwintering strategy. But local overwintering in central Europe is also a possible strategy for which several indications exist. Apart from anecdotic evidenc...

Unanswered key questions in bark beetle-plant interactions concern host finding in species attacking angiosperms in tropical zones and whether management strategies based on chemical signaling used for their conifer-attacking temperate relatives may also be applied in the tropics. We hypothesized that there should be a common link in chemical signa...

AbstractUV‐absorbing films and nets are frequently used as covering materials for netted greenhouses and film tunnels in protected cultivation systems. This study explored the effects of such materials on the dispersal behaviour of western flower thrips (WFT), Frankliniella occidentalis, in flight cages under greenhouse conditions with additional a...

To determine the effects of neem active ingredients (azadirachtin) on the entomopathogenic nematode Heterorhabditis bacteriophora and the plant-parasitic nematode Meloidogyne incognita, the nematodes were separately treated with different concentrations of NeemAzal-U (i.e., 0.06%, 0.3% and 0.6%) and its blank formulation. Direct exposure of both ne...

Only few studies are available dealing with the relation between winter host density and spatial distribution and spring colonization of winter cereals by the host-alternating cereal aphid species Rhopalosiphum padi and Metopolophium dirhodum. Large-scale studies in climatically different agroecosystems in Germany from 2004 to 2006 revealed for R.p...

The occurrence of Fusarium crown and root rot was evaluated on 8 selected asparagus fields in Lower Saxony, Germany, during the harvest periods May and June and in autumn 2008 and 2009. The incidence of infection by Fusarium spp. depended on location and season. The peak of Fusarium infection arose during the harvest in June with an average of 64 a...

The study aimed at determining thrips species composition and thrips population density on French bean planted as a sole crop and as an intercrop with either sunflower, Irish potato, or baby corn, in various combinations. Field experiments were conducted in two seasons to examine: (1) thrips population development and thrips species composition ove...

Entomopathogenic fungi are widely used as biological control agents against a broad range of insect and arachnid pests. However, the control efficacy of entomopathogenic fungi is variable because of unfavourable and fluctuating environmental conditions and intrinsic factors. One strategy to enhance entomopathogenic fungi efficacy is a combined use...

Western flower thrips (WFT), Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), is an important pest of French beans in Kenya. However, information on the feeding activity and oviposition preference of WFT on crop and weed hosts associated with French beans in Kenya and other parts of the world is lacking. To determine the feeding and...

The complex and specific interplay between thrips, tospovirus and their shared host plant, has led to outbreaks of crop disease epidemics of economic and social importance. The exact details of the processes promoting the vector-virus-host interaction and their coordinated evolution, increases our understanding of the general principles involved in...

Side effects of two commercial neem products, NeemAzal-T/S (1% azadirachtin) as foliar application and NeemAzal-U (17% azadirachtin) as soil application were tested in labora-tory bioassays against about-to-emerge adults and adults of an aphelinid, Eretmocerus warrae (EW) an efficient parasitoid of the whitefly Bemisia tabaci (WF) in Thailand. Hatc...

Extrakte aus dem Holz von Quassia amara (Simaroubaceae) werden aufgrund ihrer insektiziden Eigenschaften bereits seit Beginn des 20. Jahrhunderts zur Schädlingskontrolle verwendet. Zurzeit ist in Deutschland die Verwendung von selbsthergestellten Spritzbrühen auf Basis von Quassiaextrakten im eigenen Betrieb erlaubt, ein einfach anzuwendendes Präpa...

Studies were conducted in tropical greenhouses to elucidate the role of UV light (UV) for the orientation and flight behavior of the thrips Ceratothripoides claratris (Shumsher) (Thysanoptera: Thripidae), an important pest on tomato (Lycopersicum spp.), in the hot and humid tropics of South-East Asia. Four greenhouse types characterized by differen...

Host-finding behaviour of Prostephanus truncatus was evaluated in a four-choice olfactometer for reactions to odours of maize, cassava chips, wheat, cowpea (a non-host plant), and woody plant species in which reproduction has been observed, and of organisms associated with maize stores. P. truncatus reacted in general to odours from starchy commodi...

Number of degree days available to the coffee berry borer (above 14.9C) in three locations in East Africa and one in South America. (0.08 MB DOC)

Warming Tolerance (WT) and Thermal Safety Margin (TSM) (calculated after Deutsch et al., 2008) for Hypothenemus hampei in three locations in East Africa and one in South America. (0.12 MB DOC)

French abstract - resume (0.03 MB DOC)

Spanish Abstract - Resumen (0.03 MB DOC)

Studies were conducted in tropical greenhouses to elucidate the role of UV light (UV) for the orientation and flight behavior of the thrips Ceratothripoides claratris (Shumsher) (Thysanoptera: Thripidae), an important pest on tomato (Lycopersicum spp.), in the hot and humid tropics of South-East Asia. Four greenhouse types characterized by differen...

The toxicity of 1-, 5-, 10- and 14-day-old residues of azadirachtin (5 and 10 ml/lw), spinosad (2 and 4 ml/lw) and avermectin (2 and 4 ml/lw) on tomato plants was evaluated against foliage-inhabiting life stages of Liriomyza sativae Blanchard in air-conditioned rearing rooms and greenhouses in central Thailand (Bangkok). Azadirachtin and spinosad c...

Several parasitoids of African origin have been introduced to coffee producing areas of the Americas and Asia as biological control agents of the coffee berry borer (CBB) Hypothenemus hampei (Coleoptera: Curculionidae). These parasitoids have become established in the field but their effect on the CBB has been limited. A two-year field study in Wes...

An investigation of the diversity and distribution of wild crucifer species and their importance for cultivated crucifers was conducted during 2005 and 2006 in the highland and mid-altitude semi-arid areas of Kenya. Thirteen species of wild crucifers in nine genera were recorded: Raphanus raphanistrum, Erucastrum arabicum, Sisymbrium officinale, Cr...

Models used to simulate changes in populations of cereal aphids need to be compared and validated if they are ever to be improved sufficiently for wide-scale use in crop protection. With this in mind, simulation runs using the models SIMLAUS, LAUS, and GETLAUS01 were tested over several years using data collected in different regions of Germany. Th...

The suitability of a mixture of plaster of Paris and charcoal as a means to regulate the moisture content of coffee berries and the relative humidity (moisture conditions) of the rearing environment and its impact on rearing the coffee berry borer (CBB), Hypothenemus hampei (Ferrari) (Coleoptera: Curculionidae), was evaluated under laboratory condi...

The migration of cereal aphids and the time of their arrival on winter cereal crops in autumn and spring are of particular importance for plant disease (e.g. barley yellow dwarf virus infection) and related yield losses. In order to identify days with migration potentials in autumn and spring, suction trap data from 29 and 45 case studies (location...

Coffee is predicted to be severely affected by climate change. We determined the thermal tolerance of the coffee berry borer, Hypothenemus hampei, the most devastating pest of coffee worldwide, and make inferences on the possible effects of climate change using climatic data from Colombia, Kenya, Tanzania, and Ethiopia. For this, the effect of eigh...

The thrips Ceratothripoides claratris is an efficient vector of the Capsicum chlorosis virus (CaCV). Transmission studies with a natural population of C. claratris found in a greenhouse ‘GH’ and a ‘colony’ derived from this ‘GH’ population by selection and inbreeding resulted in lowering the percentage of viruliferous individuals within the ‘colony...

Plutella xylostella is the most abundant and damaging pest of cruciferous crops in Kenya and has gained economic importance over the years. During a survey conducted in the major crucifer areas of Kenya a number of wild crucifers recorded in the region were found infested with diamondback moth. As a result, research was conducted in the laboratory...

Cereal aphid populations (Homoptera: Aphididae) in winter wheat and winter barley were evaluated in the autumn and early spring of two subsequent vegetation periods (2004/2005 and 2005/2006) by D-VAC mobile suction sampler, visual counts, and plant sampling in order to compare the efficiency of different cereal aphid survey techniques. Plant sampli...

The sweet potato whitefly Bemisia tabaci (WF) can be controlled by two commercial neem products, NeemAzal-T/S® (1% azadirachtin) for foliar application, and NeemAzal-U (17% azadirachtin) for soil application, alongwith two biorational products of microbial origin, Abamectin (avermectin) and Success® (spinosad). Side effects of these products were t...

Cereal aphids (Homoptera: Aphididae) yearly infest winter wheat occasionally leading to significant yield reduction when biotic and abiotic factors are optimal for rapid population growth. Within the host plant complex, influences of eight winter wheat cultivars on the development of cereal aphids was studied in a two-year project focussing on the...