Nanoparticle-delivered RNAi-based pesticide target screening for the rice pest white-backed planthopper and risk assessment for a natural predator

Vacuolar-type (H+)-ATPase (vATPase) is a conserved multi-subunit eukaryotic enzyme composed of 14 subunits that form a functional complex consisting of an ATP-hydrolytic domain (V1) and a proton-translocation domain (V0). ATP hydrolysis and subsequent H+ translocation rely heavily on a fully assembled V1/V0 complex. Since vATPase is crucial for insect survival, it is a viable molecular target for pest control. However, detailed functional analyses of the 14 subunits and their suitability for pest control have not been fully explored in a single insect species. In this study, we identified 22 vATPase subunit transcripts that correspond to 13 subunits (A1, A2, B, C, D, E, F, G, H, a1, a2, c and d) in the white-backed planthopper (WBPH), Sogatella furcifera, a major hemipteran pest of rice. RNAi screens using microinjection and spray-based methods revealed that the SfVHA-F, SfVHA-a2 and SfVHA-c2 subunits are critical. Furthermore, star polymer (SPc) nanoparticles were utilized to conduct spray-induced and nanoparticle-delivered gene silencing (SI-NDGS) to evaluate the pest control efficacy of RNAi targeting the SfVHA-F, SfVHA-a2 and SfVHA-c2 transcripts. Target mRNA levels and vATPase enzymatic activity were both reduced. Honeydew excreta was likewise reduced in WBPH treated with dsRNAs targeting SfVHA-F, SfVHA-a2 and SfVHA-c2. To assess the environmental safety of the nanoparticle-wrapped dsRNAs, Cyrtorhinus lividipennis Reuter, a major natural enemy of planthoppers, was also sprayed with dsRNAs targeting SfVHA-F, SfVHA-a2 and SfVHA-c2. Post-spray effects of dsSfVHA-a2 and dsSfVHA-c2 on C. lividipennis were innocuous. This study identifies SfVHA-a2 and SfVHA-c2 as promising targets for biorational control of WBPH and lays the foundation for developing environment-friendly RNAi biopesticides.

Phenology model development for Neodryinus typhlocybae: Evaluation of phenological synchrony with its host, Metcalfa pruinosa

The invasive species Metcalfa pruinosa has inflicted significant economic losses in various European and Asian regions. To combat this pest, the parasitoid wasp Neodryinus typhlocybae has been effectively introduced in Europe. Despite its success, research on the field occurrence patterns of N. typhlocybae, particularly its phenology, remains scarce. This study aims to develop a degree-day model for predicting the adult emergence of N. typhlocybae from overwintering cocoons and to assess the phenological synchrony between N. typhlocybae adults and the nymphal stages of M. pruinosa in Korea. In this study, we estimated the thermal parameters of N. typhlocybae under field temperatures and six constant temperatures (13.92, 17.71, 18.53, 20.53, 22.78, and 24.03 °C) conditions. The lower developmental temperature was estimated using the values of the coefficient of variation for the cumulative degree days of emerged individual adults. The estimated lower developmental threshold temperature was 12.3 °C. With this developmental threshold, a degree-day model was developed, and this model well-predicted emergence in field conditions. By simulating this developed model with the actual occurrence of the nymphal stages of its host, M. pruinosa, adult wasp emergence was estimated to be 1.5 weeks later than the first instar nymph of the host but faster than other nymphal stages of M. pruinosa. Thus, the findings in this study would be helpful in determining the possibility of establishing N. typhlocybae and improving the management efficiency of M. pruinosa.

Sublethal chemical stimulation of arthropod parasitoids and parasites of agricultural and environmental importance

An increasing number of studies have reported stimulation of various organisms in the presence of environmental contaminants. This has created a need to critically evaluate sublethal stimulation and hormetic responses of arthropod parasitoids and parasites following exposure to pesticides and other contaminants. Examining this phenomenon with a focus on arthropods of agricultural and environmental importance serves as the framework for this literature review. This review shows that several pesticides, with diverse chemical structures and different modes of action, applied individually or in combination at sublethal doses, commonly stimulate an array of arthropod parasitoids and parasites. Exposure at sublethal doses can enhance responses related to physiology (e.g., respiration, total lipid content, and total protein content), behavior (e.g., locomotor activity, antennal drumming frequency, host location, and parasitization), and fitness (longevity, growth, fecundity, population net and gross reproduction). Concordantly, the parasitic potential (e.g., infestation efficacy, parasitization rate, and parasitoid/parasite emergence) can be increased, and as a result host activities inhibited. There is some evidence illustrating hormetic dose-responses, but the relevant literature commonly included a limited number and range of doses, precluding a robust differentiation between sub- and superNOAEL (no-observed-adverse-effect level) stimulation. These results reveal a potentially significant threat to ecological health, through stimulation of harmful parasitic organisms by environmental contaminants, and highlight the need to include sublethal stimulation and hormetic responses in relevant ecological pesticide risk assessments. Curiously, considering a more utilitarian view, hormesis may also assist in optimizing mass rearing of biological control agents for field use, a possibility that also remains neglected.

A predatory social wasp does not avoid nestmates contaminated with a fungal biopesticide

Fungus-based biopesticides have been used worldwide for crop pest control as a safer alternative to chemical pesticides such as neonicotinoids. Both agrochemicals can be lethal and may also trigger side effects on the behavioral traits of non-target social insects, which play a crucial role in providing essential biological pest control services in agroecosystems. Here, we evaluated whether a commercial formulation of the entomopathogenic fungus Beauveria bassiana or the neonicotinoid imidacloprid causes mortality in foragers of Mischocyttarus metathoracicus. These social wasps are natural enemies of caterpillars and other herbivorous insects and inhabit both urban and agricultural environments in Brazil. We also tested whether wasps discriminate between biopesticide-exposed and unexposed conspecifics. Through a combination of laboratory (survival assay) and field experiments (lure presentation), along with chemical analyses (cuticular hydrocarbon profiles), we showed that topic exposure to the label rate of each pesticide causes a lethal effect, with the biopesticide exhibiting a slower effect. Moreover, wasps do not discriminate biopesticide-exposed from unexposed conspecifics, likely because of the similarity of their cuticular chemical profiles 24 h after exposure. Overall, the delayed lethal time at the individual level, combined with the indistinctive chemical cues of exposure and the lack of discrimination by conspecifics suggests that the fungal biopesticide may ultimately pose a threat to the colony survival of this predatory wasp.

Cannibalistic enemy-pest model: effect of additional food and harvesting

Biological control using natural enemies with additional food resources is one of the most adopted and ecofriendly pest control techniques. Moreover, additional food is also provided to natural enemies to divert them from cannibalism. In the present work, using the theory of dynamical system, we discuss the dynamics of a cannibalistic predator prey model in the presence of different harvesting schemes in prey (pest) population and provision of additional food to predators (natural enemies). A detailed mathematical analysis and numerical evaluations have been presented to discuss the pest free state, coexistence of species, stability, occurrence of different bifurcations (saddle-node, transcritical, Hopf, Bogdanov-Takens) and the impact of additional food and harvesting schemes on the dynamics of the system. It has been obtained that the multiple coexisting equilibria and their stability depend on the additional food (quality and quantity) and harvesting rates. Interestingly, we also observe that the pest population density decreases immediately even when small amount of harvesting is implemented. Also the eradication of pest population (stable pest free state) could be achieved via variation in the additional food and implemented harvesting schemes. The individual effects of harvesting parameters on the pest density suggest that the linear harvesting scheme is more effective to control the pest population rather than constant and nonlinear harvesting schemes. In the context of biological control programs, the present theoretical work suggests different threshold values of implemented harvesting and appropriate choices of additional food to be supplied for pest eradication.

Aphaereta pallipes (Hymenoptera: Braconidae) and Dirhinus anthracia (Hymenoptera: Chalcididae) associated with Peckia (Euboettcheria) collusor (Diptera: Sarcophagidae) in Brazil

Flies of the Sarcophagidae family are widely distributed in the world, occupying different habitats. Some species have a high degree of synanthropy and are therefore often found in households in the urban environment. In Brazil, there is still little information related to the natural enemies of these insects in the urban environment, where population control is strictly chemical. Therefore, larvae and pupae of Peckia (Euboettcheria) collusor (Curran and Walley) (Diptera: Sarcophagidae) species were exposed in an urbanized location, and the presence and prevalence of parasitoids in the natural control of these immature stages was evaluated. We report for the first time the species Aphaereta pallipes (Say) (Hymenoptera: Braconidae) and Dirhinus anthracia Walker (Hymenoptera: Chalcididae), associated with P. (E.) collusor, highlighting the importance of these parasitoids in natural control in the urban environment, in addition to expanding the list of hosts for both parasitoid species and the distribution of this parasitoid-host interaction for Brazil and the Neotropical region.

Sulfoxaflor adversely influences the biological characteristics of Coccinella septempunctata by suppressing vitellogenin expression and predation activity

Sulfoxaflor is a widely used sulfoximine insecticide that has been regarded as an important alternative insecticide for IPM strategies, but a comprehensive study of its potential ecological toxicity is still lacking. In the present work, the growth, longevity, predation and reproduction toxicity of Coccinella septempunctata caused by sulfoxaflor were evaluated. In addition, the potential mechanisms of decreased fecundity in C. septempunctata were investigated by analyzing the transcriptional and protein levels of reproduction-related gene vitellogenin (Vg). In a 20-day acute contact toxicity test, decreased survival proportion, pupation rate, adult emergence ratio, and increased hazard quotient (HQ) values were observed. Moreover, sublethal dosages of sulfoxaflor significantly inhibited the predation, longevity, fecundity and net reproduction rate of progeny. In addition, LR₃₀ of sulfoxaflor dramatically down-regulate the mRNA-expression (F₀: 65.38-fold, F₁: 2.24-fold) and protein content (F₀: 1.35-fold, F₁: 1.36-fold) of Vg in the F₀ and F₁ generations. These results suggested that sulfoxaflor could inhibit the gene and protein content of Vg, thereby reducing the fecundity of C. septempunctata. Our study indicated that sulfoxaflor has potential risks to parent and progeny generations of C. septempunctata. These results provide valuable reference for optimal usage of sulfoxaflor in IPM systems.

Historical and Contemporary Perspectives on the Biological Control of Aphids on Winter Cereals by Parasitoids in South America

Aphids are worldwide pests, and in South America, they harm many crops including winter cereals. In the 1970s, the rapid expansion of the wheat crop area in the subtropical region of South America led to growth of aphid populations. The wide availability of food, associated with the low effectiveness of natural biological control, put the aphid populations out of balance, requiring intensive use of insecticides. At the end of the decade, biological control programs of aphids were initiated in Argentina, Brazil, and Chile, including the importation of natural enemies (mainly parasitoids), followed by their laboratory rearing and field release. With decreased use of highly hazardous pesticides, biological control by introduced and already-present parasitoid species was enhanced. The program was very successful and aphid populations have been kept at low levels. This review article explores the history of this program and its current status. In modern day agriculture, with intense multiple cropping systems, adoption of several conservation practices, and increased cultivation of wheat in tropical regions, we discuss ways to keep this program effective to maintain aphid populations on cereal crops at low acceptable levels through employing biological control agents.

Defensive behavior of the invasive alien hornet, Vespa velutina, against color, hair and auditory stimuli of potential aggressors

Background

During recent years, invasion of the yellow-legged hornet (Vespa velutina) has occurred in Europe, Korea and Japan, and stinging accidents often occur as some V. velutina nests are in places where humans can reach them. Misleading information regarding precautionary measures for mitigating wasp attacks has only exacerbated the situation. In this study, we sought to identify appropriate countermeasures by analyzing wasp defensive behavior, with a focus on color, hair and auditory stimuli.

Methods

Defensive behavior was analyzed using video recordings by creating an experimental frame to attach experimental bundles to nine V. velutina nests in Daegu and Gyeongbuk, South Korea. For the color experiment, eight-color and single-color tests were conducted with bundles of eight colors (black, brown, yellow, green, orange, gray, red and white), and the difference in defensive behavior was tested between black hair/hairless and green hair/black hairless configurations.

Results

When presented simultaneously with bundles of eight different colors, V. velutina showed the greatest and the longest defensive behavior against the black bundle, followed by brown. A similar response was observed in single-color tests. Furthermore, there was no significant difference in the defensive behavior against black hair and black hairless, but the duration of defensive behavior was longer for black hair. A comparison between green hair and black hairless stimuli indicated that wasps are more sensitive to color than to hair texture. Vespa velutina showed no discernible responses when exposed to selected auditory stimuli (human conversation and loud music). Dark colors and dark hair are characteristic features of potential predators, to which wasps are evolutionarily predisposed, and are accordingly likely to provoke strong defensive responses. The results of this study provide scientifically credible information that can be used to base appropriate precautionary measures against wasp attacks.

Assessing the conservation and enhancement value of revegetated strips on arthropod assemblages in a pasture landscape

Examining population dynamics of arthropod communities in habitats neighboring arable lands is essential to understanding how agroecosystems can be engineered to enhance ecosystem services and contribute to sustainable intensification. Arthropods comprise the bulk of faunal biomass on farms, are taxonomically diverse, and are the main drivers of many ecosystem functions. This study aimed to compare arthropod assemblages in revegetated strips of native plants and exotic pastures, and examine taxa of beneficial arthropods in revegetated strips and adjacent pasture in early spring (September 2009) and mid-summer (December 2009-January 2010) on two farms in southeastern Gippsland, Victoria, Australia. Arthropod community assemblages were distinctly different between revegetated strips and adjacent pasture with the exception of functional groups in early spring. Several taxa of beneficial arthropods including Carabidae (ground beetles) and Syrphidae (hoverflies) were of similar abundance in the two habitats. Only Formicidae (ants) were of higher abundances in revegetated strips compared to adjacent pasture in both seasons. Five of the 10 ant genera present, seven spider families and Dolichopodidae flies (long-legged flies) were found exclusively in revegetated strips. Apidae (bees) and Tachinidae (tachinid flies) had higher abundances in revegetated strips compared to 80 m into the adjacent pasture in mid-summer. Lycosidae (wolf spiders) were more abundant along the edge of revegetated strips and 20 m into adjacent pasture compared to the center (core) of revegetated strips and 80 m into pasture. These results illustrate that beneficial arthropods use revegetated strips as refugia and that revegetated strips clearly enhanced biological conservation of arthropods in pasturelands. Relevance of findings to enhanced biological control is also discussed.

Respiration, predatory behavior and prey consumption by Podisus nigrispinus (Heteroptera: Pentatomidae) nymphs exposed to some insecticides

Podisus nigrispinus Dallas (Heteroptera: Pentatomidae) preys on insect pests in eucalyptus plantations where it can be exposed to insecticides used in pest control. The effect of insecticides on non-target natural enemies requires further study. The objective of the present study was to evaluate the side-effects of Bacillus thuringiensis (Bt), permethrin, tebufenozide and thiamethoxam on third instar nymphs of the predator P. nigrispinus in the laboratory. The toxicity of insecticides for this insect was determined by estimating their lethal concentrations. Podisus nigrispinus behavior after exposure to insecticides was analyzed using a video tracking system and the respiratory rate with a respirometer. Prey/nymph consumption was assessed after 24 h of starvation. The preference of P. nigrispinus nymphs, for prey treated or not with the insecticides, was evaluated in free choice tests. The insecticides Bt [LC₅₀ = 1.10(0.83-1.46) mg mL^-1], permethrin [LC₅₀ = 0.25(0.17-0.34) mg mL^-1], tebufenozide [LC₅₀ = 5.71(4.17-7.57) mg mL^-1] and thiamethoxam [LC₅₀ = 0.04(0.02-0.06) mg mL^-1] are toxic to P. nigrispinus nymphs. Bt and the insecticides tebufenozide, permethrin and thiamethoxam reduced the respiratory rate of P. nigrispinus. The insecticides permethrin, tebufenozide and thiamethoxam affect the locomotion of this insect's nymphs. Prey treated with Bt, permethrin and thiamethoxam are less preferred by P. nigrispinus. The survival of the nymphs of this predator was 93.3%, 66.7%, 56.6%, 0% and 0% in the control, tebufenozide, Bt, permethrin and thiamethoxam treatments, respectively. In addition, the reduction of prey consumption, treated with neurotoxic insecticides, reduces the predatory potential of this natural enemy. Bt and tefubenozide present low toxicity for P. nigrispinus, but the neurotoxic products have low compatibility with this natural enemy and, therefore, are not recommended, with this predator in the management of forest insect pests.

Non-target toxicity of nine agrochemicals toward larvae and adults of two generalist predators active in peach orchards

Chrysoperla externa and Coleomegilla quadrifasciata are important biological control agents in peach orchards. However, orchard management with these predatory insects is viable only by using selective agrochemicals. The objective of this study is to evaluate the toxicity of nine agrochemicals used in peach orchards in larval and adult stages of the C. externa and C. quadrifasciata in laboratory conditions. The bioassays followed the methodologies proposed by the International Organization for Biological and Integrated Control (IOBC). Larvae and adults of C. externa and C. quadrifasciata were exposed to the dry residues of these products. Lethal and sublethal effects were evaluated in bioassays with the larval and adult stages of both predators. The agrochemicals were classified according to the IOBC guidelines. The insecticide chlorantraniliprole was harmless (class 1) to the larval stage of C. externa and C. quadrifasciata. Azadirachtin, copper 25% + calcium 10%, and deltamethrin were harmless to the adult stage of both insect species. The organophosphates fenitrothion and malathion were harmful (class 4) to both species in the larval and adult stages and should not be used in peach orchards. Therefore, this study demonstrates the importance of toxicity and the lethal and sublethal effects of these agrochemicals to better determine their compatibility with IPM in peach production.

Identification and Characterization of the Pheromones in the Minute Pirate Bug Orius sauteri (Heteroptera: Anthocoridae)

The flower bug Orius sauteri is a generalist predator that occurs throughout Japan, and is a promising indigenous natural enemy for micro-pests such as thrips, aphids, and spider mites. We aimed to manipulate the attraction, dispersal, and settlement behavior of Orius bugs using natural chemical substances emitted by the bugs themselves. To identify potential candidates, we screened components in the whole-body extract of O. sauteri based on antennal response and then determined their chemical structure. A gas chromatograph electroantennographic detector (GC/EAD) indicated that the antennae of males responded to two components in the extract of females. GC/mass spectrometry (MS) showed that these two components were octenal and octadienal. Derivatization or GC-FT-IR analysis identified these components as (E)-2-octenal and (E)-2,7-octadienal. To assess the effect of these components on O. sauteri behavior, we conducted two assays. A field bioassay demonstrated that a blend of the two components functioned as a sex pheromone, and a dispersal assay showed that (E)-2-octenal generated a dose-dependent dispersal response. Our study will provide baseline information for enhancing the retention of O. sauteri on important commercial crops to prey on pest species.

Volatiles from Maruca vitrata (Lepidoptera, Crambidae) host plants influence olfactory responses of the parasitoid Therophilus javanus (Hymenoptera, Braconidae, Agathidinae)

Plants damaged by herbivores are known to release odors attracting parasitoids. However, there is currently no information how leguminous plants damaged by the pod borer Maruca vitrata attract the exotic larval parasitoid Therophilus javanus, which was imported into Benin from the putative area of origin of the pod borer in tropical Asia for assessing its potential as a biological control agent. In this study, we used Y-tube olfactometer bioassays to investigate T. javanus response towards odors emitted by four M. vitrata-damaged host plants: cowpea Vigna unguiculata, the most important cultivated host, and the naturally occurring legumes Lonchocarpus sericeus, Sesbania rostrata and Tephrosia platycarpa. Olfactory attraction of T. javanus was influenced by the species of plant damaged by the pod borer. Moreover, odors released from M. vitrata-infested host plant organs (flowers and pods) were discriminated over non-infested organs in cowpea and T. platycarpa, respectively. These results are discussed in the context of the possible impact of M. vitrata host plants on T. javanus foraging activity and subsequent establishment in natural environments following experimental releases.

A random survival forest illustrates the importance of natural enemies compared to host plant quality on leaf beetle survival rates

Background

Wetlands are habitats where variation in soil moisture content and associated environmental conditions can strongly affect the survival of herbivorous insects by changing host plant quality and natural enemy densities. In this study, we combined natural enemy exclusion experiments with random survival forest analyses to study the importance of local variation in host plant quality and predation by natural enemies on the egg and larval survival of the leaf beetle Galerucella sagittariae along a soil moisture gradient.

Results

Our results showed that the exclusion of natural enemies substantially increased the survival probability of G. sagittariae eggs and larvae. Interestingly, the egg survival probability decreased with soil moisture content, while the larval survival probability instead increased with soil moisture content. For both the egg and larval survival, we found that host plant height, the number of eggs or larvae, and vegetation height explained more of the variation than the soil moisture gradient by itself. Moreover, host plant quality related variables, such as leaf nitrogen, carbon and phosphorus content did not influence the survival of G. sagittariae eggs and larvae.

Conclusion

Our results suggest that the soil moisture content is not an overarching factor that determines the interplay between factors related to host plant quality and factors relating to natural enemies on the survival of G. sagittariae in different microhabitats. Moreover, the natural enemy exclusion experiments and the random survival forest analysis suggest that natural enemies have a stronger indirect impact on the survival of G. sagittariae offspring than host plant quality.

Electronic supplementary material

The online version of this article (10.1186/s12898-018-0187-7) contains supplementary material, which is available to authorized users.

Spatial Distribution of Megacopta cribraria (Hemiptera: Plataspidae) Adults, Eggs and Parasitism by Paratelenomus saccharalis (Hymenoptera: Platygastridae) in Soybean

Since 2014, populations of the kudzu bug, Megacopta cribraria (F.) (Hemiptera: Plataspidae), have declined in the southeastern United States and seldom require treatment. This decline follows the discovery of Paratelenomus saccharalis (Dodd; Hymenoptera: Platygastridae), a non-native egg parasitoid. The objective of this project was to observe the temporal and spatial dynamics of P. saccharalis parasitism of kudzu bug egg masses in commercial soybean fields. Four fields were sampled weekly for kudzu bugs and egg masses at a density of one sample per 0.6 ha. Sampling commenced when soybean reached the R2 maturity stage and continued until no more egg masses were present. Responses including kudzu bugs, egg masses, and parasitism rates were analyzed using ANOVA, Spatial Analysis by Distance Indices (SADIE), and SaTScan spatial analysis software. Egg masses were collected from the field, held in the lab and monitored for emergence of kudzu bug nymphs or P. saccharalis. Kudzu bug populations were generally lower than previously reported in the literature and spatial aggregation was not consistently observed. Egg parasitism was first detected in early July and increased to nearly 40% in mid-August. Significant spatial patterns in parasitism were observed with spatio-temporal clusters being loosely associated with clusters of egg masses. There were no significant differences in parasitism rates between field margins and interiors, suggesting that P. saccharalis is an effective parasitoid of kudzu bug egg masses on a whole-field scale.

Costs and benefits of omnivore-mediated plant protection: effects of plant-feeding on Salix growth more detrimental than expected

Predators can decrease herbivore damage to plants, and this is often assumed to be beneficial to plant growth/reproduction without actual quantification. Moreover, previous studies have been biased towards strict carnivores and neglected the role of omnivorous predators in prey-suppression. Here, we examined the costs (reduction in growth) and benefits (increase in growth) of enemy-mediated plant protection via the omnivorous (prey and plant-feeding) Orthotylus marginalis, relative to herbivory by a detrimental insect pest of Salix spp. plantations, the beetle Phratora vulgatissima. In a first experiment, we compared the cost of adult beetle versus omnivore nymph plant-feeding, and assessed the (non-) additive effects of the two types of damage. In a second experiment, we quantified the reduction in plant damage resulting from beetle-egg feeding by omnivorous nymphs and subsequent benefits to plants. We found that plant-feeding by omnivores negatively affected plant growth and this effect was similar to the cost imposed by beetle herbivory. Furthermore, simultaneous damage effects were additive and more detrimental than individual effects. While egg-predation by omnivore nymphs completely prevented beetle damage to plants, there was no difference in plant growth relative to only herbivore-damaged plants and growth was still reduced compared to control plants. Thus, despite herbivore suppression, there was no benefit to plant growth of omnivore-mediated plant protection and the negative effects of omnivore plant-feeding remained. These results are a first for an omnivorous enemy, and provide novel and timely insights on the underlying assumptions of tri-trophic associations and their use for biocontrol of insect pests.

Cycloxaprid: A novel cis-nitromethylene neonicotinoid insecticide to control imidacloprid-resistant cotton aphid (Aphis gossypii)

Imidacloprid is a nicotinic acetylcholine receptor (nAChR) agonist with potent insecticidal activity. However, resistance to imidacloprid is a significant threat and has been identified in several pest species. Cycloxaprid with cis-configuration is a novel neonicotinoid insecticide, which shows high activity against imidacloprid-resistant pests. The LC50 of imidacloprid against the resistant Aphis gossypii was 14.33mgL(-1) while it was only 0.70mgL(-1) for the susceptible population, giving a resistance ratio of 20.47. In this imidacloprid-resistant population, a point mutation (R81T) located in the loop D region of the nAChR β1 subunit was found out. But this point mutation did not decrease the activity of cycloxaprid against A. gossypii. The LC50 of cycloxaprid was 1.05 and 1.36mgL(-1) for the imidacloprid-susceptible and imidacloprid-resistant populations, respectively. In addition, cycloxaprid provided better efficacies against resistant A. gossypii than imidacloprid in the fields. Although cycloxaprid was highly toxic to A. gossypii, it showed high selective activity between A. gossypii and its predominant natural enemies, Harmonia axyridis and Chrysoperla sinica. These results demonstrate that cycloxaprid is a promising insecticide against imidacloprid-resistant A. gossypii and suitable for the integrated pest management.

Pandora bullata (Entomophthoromycota: Entomophthorales) affecting calliphorid flies in central Brazil

Fungi are where one finds them, and if one seeks fungal pathogens affecting flies, then a garbage dump may be an ideal place to find both persistent, abundant fly populations and their fungal pathogens. An obvious fungal epizootic affecting the oriental latrine fly, Chrysomya megacephala (Diptera: Calliphoridae), was observed over several days in mid-February 2015 at the local garbage dump adjacent to the city of Cavalcante, northern Goiás. This site harbored large populations of both C. megacephala and a Musca sp. (Diptera: Muscidae) but only the population of oriental latrine fly was affected by any fungal pathogen and presented unusually dense populations of fresh cadavers. The fungus was identifiable as Pandora bullata (Entomophthorales: Entomophthoraceae) only after a very small number of characteristically decorated resting spores were found in these flies two months later; this represents the first Brazilian (and South American) record of this species. P. bullata is known previously from a small number of North American, European and Australian collections, all of which have included relatively abundant production of resting spores. We cannot dismiss the possibility that the extremely sparse formation of resting spores at this Brazilian site may be due to abiotic factors such as latitude (13°46'40.53″S), day length, ambient temperatures, or even the precipitation patterns in this mid-tropical montaine site. Epizootic events affecting calliphorids in Brazil strengthen the interest in entomophthoran pathogens for biological control of flies.

What works in conservation? Using expert assessment of summarised evidence to identify practices that enhance natural pest control in agriculture

This paper documents an exercise to synthesize and assess the best available scientific knowledge on the effectiveness of different farm practices at enhancing natural pest regulation in agriculture. It demonstrates a novel combination of three approaches to evidence synthesis-systematic literature search, collated synopsis and evidence assessment using an expert panel. These approaches follow a logical sequence moving from a large volume of disparate evidence to a simple, easily understandable answer for use in policy or practice. The example of natural pest regulation in agriculture was selected as a case study within two independent science-policy interface projects, one European and one British. A third funder, a private business, supported the final stage to translate the synthesized findings into a useful, simplified output for agronomists. As a whole, the case study showcases how a network of scientific knowledge holders and knowledge users can work together to improve the use of science in policy and practice. The process identified five practices with good evidence of a benefit to natural pest regulation, with the most beneficial being 'Combine trap and repellent crops in a push-pull system'. It highlights knowledge gaps, or potential research priorities, by showing practices considered important by stakeholders for which there is not enough evidence to make an assessment of effects on natural pest regulation, including 'Alter the timing of pesticide application.' Finally, the process identifies several important practices where the volume of evidence of effects on natural pest regulation was too large (>300 experimental studies) to be summarised with the resources available, and for which focused systematic reviews may be the best approach. These very well studied practices include 'Reduce tillage' and 'Plant more than one crop per field'.

First record of Closteroceruschamaeleon, parasitoid of the Eucalyptus Gall Wasp Ophelimusmaskelli (Hymenoptera, Chalcidoidea, Eulophidae), in the New World

The uniparental parasitoid Closteroceruschamaeleon (Girault) is discovered to be fortuitously present on a population of the invasive Eucalyptus Gall Wasp Ophelimusmaskelli (Ashmead) in Riverside, California. This is the first report from the New World of Closteroceruschamaeleon, which has proven to be a highly effective natural enemy of Ophelimusmaskelli in the Mediterranean Basin. The taxonomy and identification of Closteroceruschamaeleon is discussed.

Comparison of generalist predators in winter-flooded and conventionally managed rice paddies and identification of their limiting factors

Winter-flooding of rice paddies without the application of agricultural chemicals is attracting attention as a new agricultural method for enhancing the habitat conditions of wintering waterfowl in rice paddy ecosystems throughout Japan and east Asia. Conditions in these paddies are expected to result in restoration of not only the winter habitats of waterfowl but also those of other taxonomic groups during the rice growing season. In this study, we tested whether the diversity of summer spiders––ubiquitous predators in rice paddies––was higher in the winter-flooded paddies than in the conventional ones by conducting field measurements in 31 winter-flooded and 7 conventional paddies. Limiting factors of spiders in the winter-flooded paddies were then examined. Results revealed that both the density and species richness of spiders were significantly higher in the winter-flooded paddies than in the conventional ones both before and after the insecticide application against pecky rice bug Stenotus rubrovittatus (Matsumura)(Hemiptera: Miridae) to conventional paddies. In addition, spider density and species richness in the winter-flooded paddies correlated with the availability of two prey groups––chironomids and other nematocera. These findings suggest that in the winter-flooded paddies the diversity of generalist predators is higher than in the conventional ones during the rice-growing season and that the combination of management at both the landscape and field level is likely more effective for increasing spider abundance in winter-flooded paddies.