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Introduction Agricultural intensification results in biodiversity loss through land conversion and management practices which negatively impact arthropods. The abundance and diversity of ground-dwelling predators, e.g. ground beetles (Coleoptera: Carabidae) and spiders (Araneae), are negatively affected by soil disturbances such as tillage. Reducing soil disturbances can potentially conserve arthropod populations in the field and reduce the use of chemical pest controls. The present study investigated the ground-dwelling predatory community using pitfall traps in cereal fields with three different levels of soil disturbance: conventional tillage, reduced tillage and no tillage under Conservation Agriculture management, in 2018 and 2019. Pitfall traps were placed in transects from the field margins. Overall, the activity-density of ground-dwelling predators was higher in fields with minimum soil disturbance and generally declined with increased distance to semi-natural habitats. Functional diversity, expressed by the body size of ground beetles, was also affected by soil disturbances; large ground beetles more consistently occurred in CA, while few or none of the largest ground beetles were found in RT and CT. A higher sample-heterogeneity in less disturbed fields was indicated by a more variable median and higher skewness in the number of predators in those fields. In 2019 only, species diversity was higher along field edges bordering semi-natural habitats when compared to the cropped area. Our results show that reduced tillage supports predator arthropod communities at a local scale: It also bolsters agro-ecosystem resilience by promoting a higher activity-density and by increasing the heterogeneity and functional diversity of ground-dwelling predators. Implications for insect conservation The results obtained in the present study show that soil disturbances significantly influence arthropod abundance and diversity. Conservation of epigeic natural enemies in the agricultural landscape is improved by reducing soil-disturbing events such as tillage.

Damage to a host plant caused by insect herbivory and pathogens induces defence responses in the plant. Defence responses induced by hemipterans are often distinct from those elicited by chewing herbivores. Furthermore, hemipterans and pathogens induce a similar set of specific responses, which cannot only affect different species of insect herbivores, but also reduce the severity and symptoms of pathogen attack. Moreover, hemipteran predators can also induce plant resistance against insect herbivory, e.g. by probing/feeding attempts or via ovipositing into plant tissue. The aim of this review was to review only studies that involved direct induced resistance, induced by insects, such as hemipterans and predators, on subsequent attack by insect pests and pathogens. The criterion applied was that a reduced activity of the aggressors was measured, accompanied by direct defence responses. Studies on herbivore-induced plant volatiles (HIPVs) were excluded as our focus is on induced resistance that would also have effect on pathogens that cannot themselves respond to HIPVs. Out of a total of 375 studies generated by a systematic search, 24 studies fulfilled the criteria. The review shows that the release of hemipteran predators for biological control in greenhouses may also lead to induced resistance against subsequent attackers. Monitoring of hemipterans and plant diseases are used to inform early warning systems for pest management. Accordingly, a thorough understanding of the responses induced by hemipterans can facilitate further progress in crop protection strategies in both greenhouse facilities and in open field productions.

Cassava is Africa’s most important food security crop and sustains about 700 million people globally. Survey interviews of 320 farmers in three regions of Tanzania to identify their production characteristics, and interviews with 20 international whitefly/virus experts were conductedto identify adaptation strategies to lessen the impacts of cassava whiteflies and viruses due to climate change in Tanzania. Structured and pre-tested interview schedules were conducted using a multistage sampling technique. Most of the farmers (66.8%) produced cassava primarily for food, and relied mainly on their friends (43.8%) and their farms (41.9%) for cassava planting materials. Farmers significantly differed in their socio-economic and production characteristics except for gender and access to extension support (P < 0.01). A significant association was found between extension support, sources of planting materials, and reasons for growing cassava with both the control of cassava viruses and the control of whiteflies by the farmers. A significantly higher number of farmers controlled cassava viruses (38.1%) than cassava whiteflies (19.7%). The adaptation strategies most recommended by experts were: integrating pest and disease management programs, phytosanitation, and applying novel vector management techniques.The experts also recommended capacity building through the training of stakeholders, establishing monitoring networks to get updates on cassava pests and disease statuses, incorporating pest and disease adaptation planning into the general agricultural management plans, and developing climate change-pest/disease models for accessing the local and national level impacts that can facilitate more specific adaptation planning in order to enhance the farmers’ adaptive capacities.

The predatory bug, Orius majusculus (Reuter), is an important predator of thrips commercially produced for augmentative releases using the eggs of the Mediterranean flour moth Ephestia kuehniella (Zeller). In this study, we assessed the potential for using frozen adults of fruit flies, Drosophila melanogaster (Meigen), either as nymphal rearing diet or as diet throughout the entire life-cycle. We compared life-history traits and reproduction of predators when fed D. melanogaster with high lipid body content (lipid-rich) and with high protein body content (protein-rich), using a diet of 100% E. kuehniella eggs as control. We also analyzed the biochemical composition of both prey and predator in order to assess the nutritional quality of each diet, which partially explained the adequacy of the different diets for O. majusculus. There were significant differences between predators fed the two types of D. melanogaster, with the protein-rich flies as diet providing the best results in terms of mortality and fecundity. Furthermore, we show that while feeding O. majusculus throughout their development with D. melanogaster increases mortality and reduces reproduction, protein-rich D. melanogaster can be used as nymphal diet with minimal reduction in reproductivity and minimal increase in mortality.

The whiteflies belonging to the species group Bemisia tabaci transmit viruses that are the greatest constraint to the production of cassava, Africa’s most important food security crop. We studied the life history of an endemic African population of B. tabaci SSA-ESA at six constant temperatures (16, 20, 24, 28, 32, 36 °C) in controlled environment chambers, and for 10 generations in the field. Oviposition occurred between 20 and 28 °C, with highest fecundity (114.5 ± 88.2) eggs per female at 20 °C. Similarly, B. tabaci adult females average survival time was longest (19.7 days) at 24 °C, and shortest (8.5 days) at 36 °C. Immature development time decreased with increasing temperature from 59.3 days at 16 °C to 16.3 days at 28 °C, and increased above 28 °C. A constant temperature of 36 °C was lethal to eggs and first instars and no immature stage developed further to adults at this temperature. Several temperature-driven models were fitted for describing the species development, survival and reproduction using Insect Life Cycle Modelling (ILCYM®) software. Median temperature-dependent development rates in individual immature life stages were statistically described by Taylor, Briere 1 and Tb (Logan) models. Temperature-dependent mortality and senescence rates in immature stages were described by using parabolic nonlinear models. The longevity of adult females and oviposition time was best described by the Weibull distribution. Maximum population growth was predicted between 26 and 28 °C. These results will be useful for spatio-temporal analysis of climate change impacts on the distribution and abundance of this pest.

Arthropods are essential to maintaining healthy and productive agricultural systems. Apples are cultivated worldwide and rely on pollination. Honey bees are used for pollination but wild bees and other arthropods also contribute to pollination. Flower visitors can also be natural enemies or herbivores. In some cases, such as Syrphids, a group can have more than one role, adults being pollinators and the larvae being natural enemies of pests. In the present study, we assessed the biodiversity of arthropod flower visitors in four Danish apple orchards and compared the use of molecular and non-molecular techniques to study arthropod communities in agricultural ecosystems. Arthropod DNA collected from apple flowers was analysed by metabarcoding and pollinators were recorded through visual assessment in the orchards. These techniques resulted in two complementary lists of arthropods detected. Non-bee arthropods constituted a big part of the community of apple flower visitors by both methods. Metabarcoding detected 14 taxa and had 72% species resolution while visual census identified 7 different taxa with 14% species resolution. This study showed the importance of using different sampling methodologies to obtain a more accurate picture of fauna present. It also revealed the high presence of non-bee arthropods visiting flowers in apple orchards. The outcome of our study provides information regarding the effects of management practices on arthropod biodiversity, which can contribute to informing on suitable management practices to increase crop yield and maintain healthy agricultural systems.

International audience; Les bénéfices de la biodiversité fonctionnelle, notamment en terme de lutte contre les ravageurs, font l'objet de débats entre les praticiens et on sait peu de choses sur les pratiques et les motivations des agriculteurs pour favoriser cette biodiversité. Nous avons supposé que l'utilisation de méthodes de suivi aiderait les agriculteurs à mieux apprécier les bénéfices de la biodiversité fonctionnelle et les inciterait à mettre en œuvre des pratiques qui lui sont favorables. Nous avons mis en œuvre une approche globale combinant des entretiens semi-directifs et des ateliers participatifs pour décrire les pratiques et la perception des agriculteurs vis-à-vis de la biodiversité fonctionnelle et concevoir des méthodes de suivi adaptées à leurs besoins. Nos résultats fournissent des preuves empiriques que la biodiversité fonctionnelle est associée à de multiples services et dis-services. En outre, ils montrent que l'expérience et le temps disponible des agriculteurs sont deux conditions importantes à la mise en œuvre de pratiques favorables à la biodiversité fonctionnelle. Quatre attitudes principales envers la gestion de la biodiversité fonctionnelle ont été caractérisées : attentisme, naturalisme, régulation et multifonctionnalité. La connaissance de ces attitudes fournit un cadre utile pour concevoir des outils de soutien et des programmes de recherche en adéquation avec les besoins des agriculteurs.

Apple production across Europe is experiencing major yield losses due to pest damage, and the need for alternative production methods are growing. Ecological infrastructures are important to create resilient production systems and increase functional biodiversity. This study investigated perennial flower strips as a means of promoting natural enemies, thereby reducing infestation by the rosy apple aphid, Dysaphis plantaginea, and fruit damage caused by it. In 2016 and 2017, effects of perennial flower strips were assessed in eight organic apple orchards with and without flower strips. In orchards with flower strips, assessments were done in tree rows at two distances: 1st and 3rd row from the flower strip. Assessments included field samples of arthropods, visual observations of D. plantaginea symptoms and observations of predators, observations of predators directly associated with aphid colonies, and fruit damage. In 2016, significantly more symptoms of D. plantaginea were observed in the 3rd row from the flower strip compared to the 1st row from the flower strip. Both years, more predators were observed in the 1st row from the flower strip than in the 3rd row from the flower strip. In 2017, more predators were observed in orchards with a flower strip than in orchards with no flower strip, and more predators were observed inside the aphid colonies in trees in the 1st row from the flower strip than in the 3rd row from the flower strip. Predator diversity in apple trees was also positively affected by proximity to a flower strip. In conclusion, perennial flower strips consistently promote the occurrence of natural enemies in their proximity, while the effect decreases with distance. The correlation between aphid abundance and predators was not always consistent, likely because the majority of the observed predators were generalists and therefore contributing to the natural regulation of the entire herbivore complex in the apple orchards.

Ecological theory hypothesizes that plant trait diversity may be as important as the presence of specific functional traits (e.g., resistance) for the herbivore and predator communities within a population. We used experimental populations of wild woodland strawberry (Fragaria vesca) to test whether the degree of plant genotypic diversity and/or the existence of specific resistance traits play a role in the host plant's community structure specifically, the community of generalist and specialist aphids and their natural enemies. In 2019, we studied the aphid abundance and relative predator abundance in an experimental field site in Alnarp, Southern Sweden; the field consisted of plots planted with combinations of 20 different wild strawberry genotypes. These strawberry genotypes were previously identified as either susceptible to or resistant against the herbivorous beetle (Galerucella tenella). Two aphid species, Chaetosiphon fragaefolii (specialist) and the exotic Aphis gossypii (generalist) were found in the plots and of the two species A. gossypii was dominant. The abundance of the specialist aphid (C. fragaefolii) was highest in susceptible plots with high genotypic diversity, while the generalist (A. gossypii) was highest in plots with a mix of resistant and susceptible plants with high genotypic diversity. Anthocorid predators, developed significantly higher population densities in strawberry plots with high genotypic diversity. Overall, predator abundance showed a positive correlation with aphid abundance. These results show that the specific functional trait of resistance as well as plant diversity affected aphids. Knowledge about these effects can be important factors to consider when designing strawberry plantings less susceptible to aphids.

Laboratory experimentswere performed with adult female Anthocoris nemorum (Linnaeus) (Heteroptera: Anthocoridae) at 20°C ± 1°C, L16:D8, 60–70% RH to determine voracity and preference on cabbage aphids (Brevicoryne brassicae L.) (Hemiptera: Aphididae), diamondback moth larvae (Plutella xylostella L.) (Lepidoptera: Plutellidae) and Western flower thrips (Frankliniella occidentalis Pergande) (Thysanoptera: Thripidae) (model species for cabbage thrips (Thrips angusticeps Uzel) (Thysanoptera: Thripidae)). When offered individually, A. nemorum readily accepted all three species with no significant differences in consumption. When aphids and moth larvae were offered simultaneously, A. nemorum showed preference for the latter (numbers eaten and biomass consumed). When aphids and thrips were offered together, A. nemorum preferred thrips in terms of numbers eaten but preferred aphids in terms of biomass consumed. The results showed that A. nemorum is a voracious predator of B. brassicae, P. xylostella and F. occidentalis and can therefore be considered as a potential candidate for biological control in cabbage.

With frequent host shifts involving the colonization of new hosts across large geographical ranges, crop pests are good models for examining the mechanisms of rapid colonization. The microbial partners of pest insects may also be involved in or affected by colonization processes, which has been little studied so far. We investigated the demographic history of the rosy apple aphid, Dysaphis plantaginea, a major pest of the cultivated apple (Malus domestica) in Europe, North Africa and North America, as well as the diversity of its microbiota. We genotyped a comprehensive sample of 714 colonies from Europe, Morocco and the US using mitochondrial (CytB and CO1), bacterial (16s rRNA and TrnpB), and 30 microsatellite markers. We detected five populations spread across the US, Morocco, Western and Eastern Europe and Spain. Populations showed weak genetic differentiation and high genetic diversity, except the ones from Morocco and North America that are likely the result of recent colonization events. Coalescent-based inferences revealed high levels of gene flow among populations during the colonization but did not allow determining the sequence of colonization of Europe, North America and Morroco by D. plantaginea, likely because of the weak genetic differentiation and the occurrence of gene flow among populations. We found that D. plantaginea rarely hosts other endosymbiotic bacteria than its obligate nutritional symbiont Buchnera aphidicola. This suggests that secondary endosymbionts did not play an important role in the rapid spread of the rosy apple aphid. These findings have fundamental importance for understanding pest colonization processes and implications for sustainable pest control programs.

The strawberry blossom weevil (SBW), Anthonomus rubi, is a major pest in strawberry fields throughout Europe. Traps baited with aggregation pheromone are used for pest monitoring. However, a more effective lure is needed. For a number of pests, it has been shown that the attractiveness of a pheromone can be enhanced by host plant volatiles. The goal of this study was to explore floral volatile blends of different strawberry species (Fragaria x ananassa and Fragaria vesca) to identify compounds that might be used to improve the attractiveness of existing lures for SBW. Floral emissions of F. x a. varieties Sonata, Beltran, Korona, and of F. vesca, were collected by both solid-phase microextraction (SPME) and dynamic headspace sampling on Tenax. Analysis by gas chromatography/mass spectrometry showed the floral volatiles of F. x ananassa. and F. vesca were dominated by aromatic compounds and terpenoids, with 4-methoxybenzaldehyde (p-anisaldehyde) and α-muurolene the major compounds produced by the two species, respectively. Multi-dimensional scaling analyses separated the blends of the two species and explained differences between F. vesca genotypes and, to some degree, variation between F. x ananassa varieties In two-choice behavioral tests, SBW preferred odors of flowering strawberry plants to those of non-flowering plants, but weevils did not discriminate between odors from F. x ananassa and F. vesca flowering plants. Adding blends of six synthetic flower volatiles to non-flowering plants of both species increased the preference of SBW for these over the plants alone. When added individually to non-flowering plants, none of the components increased the preference of SBW, indicating a synergistic effect. However, SBW responded to 1,4-dimethoxybenzene, a major component of volatiles from F. viridis, previously found to synergize the attractiveness of the SBW aggregation pheromone in field studies.

The commercial production of Orius spp. (Hemiptera: Anthocoridae), including Orius majusculus (Reuter), relies on the use of eggs of Ephestia kuehniella (Zeller) (Lepidoptera: Pyralidae) as rearing diet. However, E. kuehniella eggs have become an expensive fodder thus increasing the price of these key biological control agents. The use of artificial diets potentially decreases the production costs. In this regard, establishing a link between dietary composition and fitness could advance the development of an optimum alternative artificial diet for these predatory insects. The aim of the current study was to test the effect of six artificial diets with different macronutrient composition on the development and reproductive fitness of O. majusculus when compared with the effect of E. kuehniella eggs. In general, nymphal survival was not affected by diet, whereas development was slightly delayed on artificial diets. However, female body mass and fecundity were significantly lower on all of the artificial diets compared with the E. kuehniella eggs diet, suggesting that artificial diets were of inferior quality. Within artificial diets, females fed the viable diet with highest content in lipid laid more eggs than those raised on the most protein-rich diets. We found there was some variation in carcass composition between the O. majusculus fed the various diets, but these variations did not match the differences found in the fitness parameters measured.

The strawberry tortrix (Acleris comariana Lienig and Zeller) (Lepidoptera: Tortricidae), is a major pest of strawberry in Denmark and southern Sweden. Chemical and electrophysiological analyses revealed a single compound, (E)-11,13-tetradecadienal (E11,13-14:Ald), in gland extracts of females eliciting a strong antennal response in conspecific males. Also (Z)-11,13-tetradecadienal (Z11,13-14:Ald) was found to be antennally active, but not detected in gland extracts. The corresponding alcohol and acetate of E11,13-14:Ald, which are biologically active in other Acleris species, were not produced by females and did not trigger electrophysiological response in males. Trapping experiments at a commercial strawberry farm in southern Sweden showed that E11,13-14:Ald and Z11,13-14:Ald, alone or in combination, attracted large numbers of males. Trap catches increased with increasing dose of E11,13-14:Ald, with traps baited with 100 µg and 1,000 µg being most attractive. Our results confirm the widespread use of E11,13-14:Ald as a key sex pheromone component in the genus Acleris. The identification of a highly attractive sex pheromone is a first step in developing pheromone-based methods for monitoring and control of A. comariana in European strawberry production. (Less)

The contribution of generalist insect predators to the control of the two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae), an herbivorous pest of many crops, is poorly understood. One of the common insect predators in strawberries is the generalist predatory bug Anthocoris nemorum L. (Hemiptera: Anthocoridae), which has the potential to contribute to the control of pest populations. The feeding of adult A. nemorum on T. urticae was assessed by sampling individuals from an organic strawberry field in Denmark, and using PCR gut content analysis to detect remains of T. urticae within their gut. In the lab, we assessed that the DNA half-life detectability was 21.5 h. Significant numbers of field-collected A. nemorum tested positive for T. urticae prey DNA, with very high numbers in June (62.8%) and August (38.8%). This study presents conclusive evidence that the generalist predator A. nemorum can contribute to the decrease of T. urticae densities in strawberry fields, although the actual contribution in the present study is probably limited because predator populations were relatively low compared to T. urticae. The abundance of T. urticae did not increase significantly during the period of sampling, suggesting that a complex of natural enemies can achieve biological control of T. urticae in protected strawberries.

We studied the food quality of the aphid Rhopalosiphum padi to the pirate bug Orius majusculus using Ephestia eggs as high-quality comparison prey. Several performance parameters were tested on individuals that had been reared and maintained on each of the two single-prey diets or on a mixed diet. All fitness parameters were lower in individuals fed aphids only, indicating poor food quality of this prey. Compared with the pure Ephestia egg diet, the mixed diet enhanced teneral mass, while adult survival and female starvation tolerance were negatively affected and all other traits were unaffected. Body protein proportions were constant across diets, whereas lipid proportion was low in the aphid treatment. Preference for aphids was lower following a monotypic aphid diet than when reared on Ephestia eggs or a mixed diet. The results confirm that R. padi is low-quality food for O. majusculus as it is for other generalist predators, even though O. majusculus may contribute significantly to population suppression of the aphid.

Whiteflies (Hemiptera: Aleyrodidae) are important insect pests causing serious damage to plants and transmitting hundreds of plant viruses. Climate change is expected to influence life history and trophic interactions among plants, whiteflies and their natural enemies. Here, we review the potential impacts of climate change on whiteflies and the likely consequences for agricultural systems. This review concludes that while climatic stress tends to negatively affect life history traits, the effects differ with the tolerance of the whiteflies and the amount of stress experienced. Whiteflies also differ in their adaptability. Better adapted species will likely experience increased distribution and abundance provided their tolerance limits are not exceeded, while species with lower tolerance and adaptation limits will suffer reduced fitness, which will have overall effects on their distribution and abundance in space and time. The majority of methods used to control whiteflies will still be useful especially if complementary methods are combined for maximum efficacy. Parasitism and predation rates of whitefly natural enemies could increase with temperature within the optimum ranges of the natural enemies, although life history traits and population growth potential are generally maximised below 30 °C. Changes in climatic suitability modifying the distribution and abundance of whiteflies, and environmental suitability for plant viruses, will likely affect epidemics of viral diseases. Greater efforts are required to improve understanding of the complex effects of climate change on multi-species and multi-trophic interactions in the agro-ecological systems inhabited by whiteflies, and to use this new knowledge to develop robust and climate-smart management strategies.

The predator Aphidoletes aphidimyza (Rondani) (Diptera: Cecidomyiidae) and the generalist entomopathogenic fungus Metarhizium brunneum Petch (Hypocreales: Clavicipitaceae) are effective biological control agents that can co-occur in pest management programmes. We exposed larvae to M. brunneum, on leaves and in soil, to explore possible outcomes of combining the two natural enemies. The number of emerging adults and their longevity were negatively affected by fungus in the soil. When exposed on leaves, adult emergence was unaffected but longevity was reduced. In choice experiments, females chose to lay eggs on fungus-free leaves: more control leaves had eggs and there were more eggs per leaf in the control. In no-choice experiments, the same frequency of females laid eggs in the treatment and control, but significantly more eggs were laid on the control leaves. Gravid A. aphidimyza can perceive M. brunneum and respond by choosing fungus-free oviposition sites, thus reducing contact between them.

Biological control with entomopathogenic fungi is a feasible option for regulation of pest insect populations. However, possible effects on beneficial arthropods must be considered. We assessed the non-target effects of the microbial biological control agent Metarhizium brunneum (isolate BIPESCO 5/F 52) applied in soil on four different predatory arthropods: the predatory mite Gaeolaelaps aculeifer (Canestrini), the predatory bug Orius majusculus (Reuter), the rove beetle Dalotia coriaria (Kraatz) and the gall midge Aphidoletes aphidimyza Rondani. All are widespread and naturally occurring in Europe, they represent different classes of arthropods and different insect orders; furthermore, their life cycles involve different levels of contact with the soil. Adult G. aculeifer, O. majusculus, and D. coriaria, and last instar A. aphidimyza larvae were exposed to natural soil (control) or natural soil inoculated with M. brunneum at a concentration of 5 × 106 conidia/g of soil; this represents a worst-case scenario. Mortality, longevity, fecundity and Metarhizium outgrowth on dead individuals were assessed for the first three species; for A. aphidimyza, only mortality (non-emergence rate) and fecundity of emerged females were assessed. The fungal treatment resulted in a significantly higher mortality of O. majusculus and D. coriaria, 96%, and 7.3% respectively, compared with 19%, and 2% for their respective controls. Mortality of G. aculeifer was not significantly affected by exposure to the fungus in the soil. Longevity of O. majusculus and D. coriaria was significantly reduced following exposure to the fungus in the soil (log-rank test: p < 0.0001, Wilcoxon test p < 0.0001 and log-rank test: p = 0.029, Wilcoxon test: p = 0.027, respectively), while G. aculeifer longevity was not affected. Fecundity of O. majusculus and D. coriaria was negatively affected following exposure to the fungus in the soil, which reduced their oviposition by 20% and 4%, respectively, compared with the control, while G. aculeifer fecundity was not affected. Aphidoletes aphidimyza larval mortality was higher following exposure to the fungus in the soil (60% dead) than in the control (40% dead) but its fecundity was not statistically significantly affected by treatment. In conclusion, the predatory arthropods studied demonstrated a range of fitness responses to M. brunneum exposure in the soil, from no response (G. aculeifer), to intermediate (D. coriaria and A. aphidimyza) and high response (O. majusculus). This study demonstrates the relevance of using several fitness parameters and different arthropod species to determine whether a biological control agent should be considered a low-risk substance with respect to non-target effects.

In the absence of effective control measures, the strawberry blossom weevil (Anthonomus rubi) (SBW) and the raspberry beetle (Byturus tomentosus) (RB) cause large (10 - >80%) losses in yield and quality in organically grown raspberry. Attractive lures for both pests were combined into a single multitrap for the economical management of both of these pests at the same time. This is one of the first approaches to pest management of non-lepidopteran insect pests of horticultural crops using semiochemicals in the EU, and probably the first to target multiple species from different insect orders. The aim is to develop optimized lures and cost-effective trap designs for mass trapping and to determine the optimum density and spatial and temporal patterns of deployment of the traps for controlling these pests by mass trapping. The combination between an aggregation pheromone that attracts Anthonomus rubi and a raspberry flower volatile that attracts Byturus tomentosus seems to be the best combination.

Occurrence of pineapple mealybug (Dysmicoccus brevipes) has been increasing at an alarming rate on pineapple in Uganda. The cause of the epidemic is unknown. This study was set out to establish whether prevailing cropping systems, production and management practices could provide an insight into the trend. A biological monitoring study that covered 150 pineapple farms was conducted in 2012 and 2013. Farms were categorised under organic and conventional systems. Mealybug population densities (mealybugs/plant) were recorded in relation to seed bed types, cropping system and soil management practices used on each farm. Mealybug population densities were lower in pineapple⿿banana intercrop system (27.8) than in a sole pineapple crop (81.8) across seasons. Earthed-up seed beds registered higher mealybug densities (84.1) than flat seed beds (31). Earthed-up seed beds created more favourable environment for mealybug multiplication than flat beds. Use of coffee husks as a soil fertility amendment promoted mealybug population build up (83.8) whereas fallowing had a reducing effect (22.7). More in-depth studies on the role of soil moisture and soil cover in mealybug population build-up in pineapples are recommended.

Floral resources are increasingly used in conservation biological control to support natural enemies of insect pests. However, the dietary value of floral resources in supporting predatory arthropods, including their effect on longevity and fecundity has not yet been systematically reviewed. To comprehensively evaluate this, the presented review summarizes published studies on the effect of various floral resources (flowers, pollen, and sugar solution (as a proxy for nectar)) on predatory arthropods. We identified 70 articles, including 628 trials, which measured predator longevity (3 4 7) and fecundity (2 8 1) when supplied with floral resources, as compared to a water only control. Across predator species, results showed that floral resources significantly increased predator longevity, especially whole flowers and sugar solution. Pollen could also prolong predator longevity but was less effective than sugar solution and flowers. The effect of flowers varied greatly among plant species, with those having open or exposed nectaries being more likely to prolong predator longevity, supposedly due to higher accessibility. Some predator species could oviposit on a diet consisting only of floral resources. The findings in the present study emphasize the value of floral resources on supporting predators. Predatory arthropods’ biological control services could be enhanced by choosing plants that favor them in conservation biological control programs.

Previous studies showed that organic farming augmented natural enemies and enhanced pest control in the agroecosystem, but the effect may change over time, as long-term application of different cultivation methods would gradually affect the agricultural systems. In this paper, spider diversity and its plant hopper control potential were assessed in paddy fields cultivated organically for 5 (OR5), 10 (OR10) and 15 (OR15) years and in conventional paddy fields (CR). The results showed that the abundance, richness and Pilou evenness of spiders in organic paddy fields were significantly higher than those in conventional paddy fields were, but no significant difference found between OR5, OR10 and OR15. There was no significant difference between Shannon Wiener index (H') of spiders in organic and conventional paddy fields. There was no distinct difference in spider assemblage composition between conventional and organic paddy fields, and a considerable overlap between the organic paddy fields with different organic farming period. Plant hopper was less abundant in organic paddy fields than conventional ones in rice blooming stage, but there was no difference in other rice growth stages. A higher number of the spider species in organic paddy fields had large temporal overlap with plant hopper than that in conventional fields. Adopting organic practices in paddy fields can maintain a high diversity of spiders across rice paddy ecosystems, although there was not significant increase of spider diversity over time after five years since transition.

Temperature influences biological processes of ectotherms including ecological interactions, but interaction strengths may depend on species-specific traits. Furthermore, ectotherms acclimate to prevailing thermal conditions by adjusting physiological parameters, which often implies costs to other fitness-related parameters. Both predators and prey may therefore pay thermal acclimation costs following exposure to suboptimal temperatures. However, these costs may be asymmetrical between predator and prey, and between the predator and different species of concurrent prey. We investigated whether thermal pre-exposure affected subsequent kill rate and predator fitness when foraging on prey that differ in ease of capture, and whether changes were primarily caused by predator or by prey pre-exposure effects. Specifically, we were interested in whether there were interactions between predator pre-exposed temperature and specific prey. Using the mesostigmatid mite Gaeolaelaps aculeifer as a generalist predator and the collembolans Folsomia candida and Protaphorura fimata as prey, we measured the impact of present temperature, predator pre-exposure temperature, prey pre-exposure temperature (all 10 or 20°C), prey species, and all interactions on prey numbers killed, predator eggs produced, and exploitation of killed prey in a full factorial design. Mites killed P. fimata in equal numbers independent of the presence of F. candida, but killed F. candida when P. fimata was absent. Mite kill rate and reproduction were significantly affected by mite pre-exposure temperature and test temperature, but not by prey pre-exposure temperature. Significantly more of the slower prey was killed than of the quicker prey. Importantly, we found significant synergistic negative interaction effects between predator cold pre-exposure and hunting prey of higher agility on predator kill rate and reproduction. Our findings show that the negative effects of cold and cold pre-exposure on kill rate and reproduction may be more severe when predators forage on quick prey. The study implies that predator cold exposure has consequences for specific prey survival following cold due to altered predation pressures, which in nature should influence the specific prey population dynamics and apparent competition outcomes. The findings exemplify how not only current but also preceding conditions affect ecological interactions, and that effect strength depends on the species involved.

Cropping practice influence arthropod species abundance and diversity in agroecosystems, thus impacting populations of insect pests and their natural enemies. A field study was conducted to investigate whether pest and natural enemy abundance was higher in organic compared with conventional strawberry fields, and whether the non-managed vegetation surrounding the field impacted natural enemy abundance and diversity in and around the field sites. The two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae), and predatory mites were sampled from strawberry leaflets and the leaves of wild herbaceous plants from the surrounding vegetation. Insect predators, hymenopteran parasitoids, spiders and herbivores were collected from the same habitats. Abundance of T. urticae was ten-fold higher in conventional compared to organic strawberry fields, whereas the ratio of spider mite to predatory mites was 9.5 times lower in organic compared with conventional strawberry fields. The 14 species of predatory mites identified were all from the family Phytoseiidae, and predominantly found on stinging nettle, Urtica dioica L. (Rosales: Urticaceae) (> 80% of individuals), in the surrounding vegetation. There was no significant effect of cropping practice on the density of insect predators and spiders, while the density of insect parasitoids and insect herbivores was higher in the organic compared to the conventional sites. Total species richness at the edge of organic fields and in the surrounding vegetation of both organic and conventional sites was higher than in the other sampling sites. This study demonstrates the major impact of cropping practice on T. urticae abundance and on the prey to predator ratio, whilst also emphasizing the importance of the surrounding vegetation as a source of natural enemies of phytophagous arthropods.

In many crops, the intensive use of pesticides causes major problems both for the environment and for natural ecosystem services. Apple is Europe's most frequently produced orchard fruit, requiring high pesticide input to combat the most important apple insect pests, Dysaphis plantaginea (Passerini) and Cydia pomonella (L.). Here we sought to control these pests by promoting natural enemies using sown perennial flower strips. We trialled these in the alleyways of organic apple orchards in seven European countries. Visual assessments over two years revealed a higher number of natural enemies on plant parts, and specifically in D. plantaginea colonies on trees, in flower strip plots than on trees in control plots with standard orchard vegetation. Trees in the flower strip plots recorded a slower D. plantaginea population increase as compared with control plots, resulting in reduced fruit damage after the second fruit drop. Likewise, from 2016–2017, the number of preadult codling moths decreased more in the flower strip plots as compared to the control plots resulting in reduced fruit damage. Our study shows on a wide continental scale that the implementation of perennial flower strips in the alleyways between apple tree rows boosts natural enemies and reduces key apple pests and the associated fruit damage. This supports the role of functional agrobiodiversity as a way to potentially reduce insecticide use in orchards and thus further promote conservation of agrobiodiversity. We also provide suggested plant composition for flower strips adapted to different European countries and recommendations for implementation and management in practice.

In the original publication of the article, in Table 1 the temperature range for fecundity of B. tabaci MED citing Bonato et al. (2007) was published incorrectly.

International audience; Supporting functional biodiversity (FB), which provides natural pest regulation, is an environmentally sound and promising approach to reduce pesticide use in perennial cultures such as apple, especially in organic farming. However, little is known about farmers' practices and motivations to implement techniques that favor FB, especially whether or not they really expect anything from FB in terms of pest regulation. In fact, FB-supporting techniques (FB-techniques) are massively questioned by practitioners due to inadequate information about their effectiveness. An interview survey was performed in eight European countries(i) to describe farmers' practices and identify promising FB-techniques: (ii) to better understand their perceptions of and values associated with FB; and (iii) to identify potential drivers of (non-) adoption. Fifty-five advisors and 125 orchard managers with various degrees of experience and convictions about FB were interviewed and a total of 24 different FB-techniques which can be assigned to three different categories (ecological infrastructures, farming practices and redesign techniques) were described. Some were well-established measures (e.g., hedges and bird houses), while others were more marginal and more recent (e.g., animal introduction and compost). On average, farmers combined more than four techniques that had been implemented over a period of 13 years, especially during their establishment or conversion period. In general, it was difficult for farmers to evaluate the effectiveness of individual FB-techniques on pest regulation. They considered FB-techniques as a whole, targeting multiple species, and valued multiple ecosystem services in addition to pest regulation. The techniques implemented and their associated values differed among farmers who adopted various approaches towards FB. Three different approaches were defined: passive, active and integrated. Their appraisal of FB is even more complex because it may change with time and experience. These findings provide empirical evidence that the practical implementation of promising techniques remains a challenge, considering the diversity of situations and evaluation criteria. Increased cooperation between researchers, farmers and advisors should more effectively target research, advisory support and communication to meet farmers' needs and perceptions.

Generalist predators potentially have access to a wide array of prey, but it is little studied how experience with specific prey affects preference for this prey. In particular, it is unknown how experience with pest prey affects predator foraging decisions in cases where the pest is nutritious but protected by a repelling, potentially deadly defence. We investigated preference of the soil predatory mite Gaeolaelaps aculeifer Canestrini for the risky pest springtail Protaphorura fimata Gisin relative to the safe non-pest springtail Folsomia candida Willem. Egg production under foraging on live or dead individuals of either prey showed that the two species had equal nutritional quality for G. aculeifer, but indicated that live F. candida were more difficult to catch than live P. fimata. Importantly, some G. aculeifer were killed by P. fimata defence secretions, demonstrating that live P. fimata are risky prey. Preference for P. fimata was generally high when mites were given a choice between a live individual of either prey, but this preference was reduced following exposure to live individuals of P. fimata. Furthermore, fewer G. aculeifer killed a prey and time until kill was longer after experience with live P. fimata. These findings indicate that live P. fimata induced a partial aversion on G. aculeifer during exposure. Our study shows that generalist predators can reduce their preference for risky prey following exposure. This indicates that generalist predators used in biological control against risky prey are most efficient against this prey if not exposed to it prior to release.

In Western Europe agricultural management was intensified in the period 1950–2010 with negative consequences for ecosystem services, such as pollination, especially in countries with a large proportion of agriculture. Farmland represents 66% of the Danish landscape, but little is known about wild bees despite that 75% of the country’s wild and cultivated plant species depend on insect pollination. Strawberry (Fragaria × ananassa) gains considerable benefits from insect pollination and abundance, species richness and functional diversity, are all important elements. We surveyed the diversity of wild bees during strawberry flowering by sampling bees with pan-traps along permanent margins bordering strawberry fields on six organic and six conventional farms in eastern Denmark and compared the results of the survey with that of sampling site farming practice and field margin forage availability. The majority of bees sampled were polylectic solitary ground-nesting bees known to forage on species of the rose family. This indicates that these bee species are potential pollinators of strawberries, and the low number of specialized bees suggests that the bee community was affected by the simplified landscapes. Temporal trends in abundance, species richness, and body size of the bees, suggest that the functional diversity of pollinator assemblages available differed for early- and late-flowering strawberries. Fewer plants species and a lower plant cover were found in the margins of sprayed fields. Abundance and diversity of the wild bees were neither correlated with the use of herbicides and insecticides, nor with plant species richness or flowering plant cover.

We determined how conidia of arthropod-pathogenic fungi on leaves affected the behavior of two predators-Orius majusculus (Hemiptera: Anthocoridae) and Phytoseiulus persimilis (Acari: Phytoseiidae)-when offered a choice between preying on two-spotted spider mites, Tetranychus urticae (Acari: Tetranychidae), in the presence or absence of infective conidia of Metarhizium brunneum (Ascomycota: Hypocreales) and Neozygites floridana (Entomophthoromycota: Neozygitaceae). The results indicate no significant relation between the presence of conidia and predator behavior. The only indication of interference is between the generalists O. majusculus and M. brunneum, with a trend towards more time spent feeding and more prey encounters turning into feeding events on leaf discs without conidia than on leaf discs with conidia. Our results show that the presence of fungal conidia does not alter the preying behavior of the predators, and using predators and fungi together is not limited by any interference between organisms in the short term.