Reduce Insecticide Use Research Articles

Canopy strip applications of Hanseniaspora uvarum combined with spinosad reduce insecticide use without compromising Drosophila suzukii control in cherry

Drosophila suzukii, a significant sweet cherry pest, has traditionally been controlled using broad-spectrum insecticides. Various yeasts are known to attract and stimulate flies to feed on yeast-covered surfaces. We investigated an attract-and-kill formulation based on the yeast Hanseniaspora uvarum and the insecticide spinosad, applied to an 80–100 cm wide canopy strip at 1-m height in six field trials across Italy and Germany to manage D. suzukii infestation in cherry. The attract-and-kill formulation, applied at a dose ranging from 21.6 to 34.9 g per hectare of spinosad, according to the training system, decreased the percentage of D. suzukii infested cherries by 41.74–84.26% and the average number of deposited eggs by 79.51–95.56%. The efficacy was comparable to the conventional application of spinosad alone, which was applied at a dose ranging from 84 to 216 g per hectare. The conventional application decreased the percentage of infested cherries by 53.00–92.00% and reduced the number of deposited eggs by 77.10–92.96%. The attract-and-kill technique led to a reduction of up to 90% of insecticide use by targeting the application on limited section of the cherry tree. The targeted approach not only minimized insecticide quantities per hectare, but also resulted in lower residue levels on treated fruits.

Integrated Pest Management: Success Stories and Key Takeaways

Integrated Pest Management (IPM) has revolutionized pest control in various agricultural settings, including orchards. By blending cultural, biological, and chemical methods, IPM aims to minimize pest damage while reducing environmental and health impacts. One of the most successful strategies within IPM is mating disruption, which uses synthetic pheromones to confuse male insects and prevent them from finding mates. This technique has been particularly effective against pests like the codling moth in apple and pear orchards, significantly reducing insecticide use by up to 90% in some regions.The implementation of IPM in orchards has numerous long-term advantages. Lower manufacturing costs, less environmental contamination, and increased worker safety have all resulted from reduced pesticide use. Furthermore, a healthier ecological balance has been promoted by the rise in natural predators and parasitoids brought about by the decrease in chemical treatments. Many growers have reported greater fruit quality due to more targeted pest control and healthier trees, despite worries that reduced use of pesticides would harm fruit quality. Important pests have also been suppressed regionally as a result of IPM's efficacy, such as the codling moth in the Pacific Northwest, whose populations have dropped to the point where little intervention is needed. Economic assessments highlight IPM's financial sustainability by demonstrating considerable long-term cost savings. According to one study, IPM adopters in apple orchards in Nova Scotia had 25% reduced pest management expenses over a ten-year period than those using conventional approaches. These results demonstrate how integrated pest management (IPM) has the ability to provide long-term, efficient pest control that is advantageous to growers, the environment, and consumers alike. IPM's widespread use attests to its effectiveness and sustainability. Integrative pest management (IPM) ensures the long-term health and production of agricultural systems by combining various pest control techniques into a balanced solution that satisfies both ecological and financial requirements.

A parasitic wasp-releasing engineering to promote ecosystem services in paddy systems

In East Asia, rice is a key crop that is subject to significant insect driven crop damage often leading to wide scale reliance on insecticides. We assessed the effects of releasing conditions (including density, frequency and distribution points) of a parastic wasp (i.e., Trichogramma japonicum) on the control efficacy it provided against two rice pest herbivores (i.e., Chilo suppressalis and Cnaphalocrocis medinalis). Optimal control was achieved by three releases of 150,000 wasps per hectare across 75 release points within a hectare rice field. A following 2-year large-scale field experiment demonstrated that the release of parasitic wasps allowed a 60.0 % reduction in insecticide use when compared to the insecticide treatment alone. Importantly, there was also a 3.7 % increase in pest control, 2.5 % increase in rice yield, and an overall 4.5 % increase in net economic benefit when the release of parasitic wasps was combined with insecticide application. This was an improvement on the use of either parasitic wasps alone or insecticide application alone. Release of parasitic wasps had co-benefits for other invertebrate predators whose abundance was increased by 65.8 % relative to the insecticide only treatment, however, this fell to a 26.4 % increase when parasitic wasps release was combined with insecticide use. Additionally, the combined treatment group of parasitic wasps and insecticides exhibited the highest net economic benefit (40488.9±593.2 Chinese Yuan (CNY) ha−1), significantly surpassing both the parasitic wasps-only treatment by 8.9 % and the treatment of no parasitic wasps and no insecticide by 21.8 %. These findings suggest that parasitic wasps releasing is a feasible approach to ecological engineering to promote multiple ecosystem services linked to greater crop yield in agroecosystems.

Resistance and susceptibility of different Barbarea (Brassicaceae) species and types to cabbage whitefly (Hemiptera: Aleyrodidae) and cabbage white butterfly (Lepidoptera: Pieridae)

Several Barbarea spp. (Brassicaceae) have been tested as trap crops for the diamondback moth Plutella xylostella L. (Lepidoptera: Plutellidae). The use of trap crops can be affected by their susceptibility to other pests, especially if the purpose is to reduce insecticide use. Barbarea rupicola Moris, B. verna (Mill.) Asch., and B. vulgaris Aiton (types G and P) (Brassicaceae) were tested for their susceptibility to the cabbage whitefly Aleyrodes proletella L. (Hemiptera: Aleyrodidae). The percentage of plants showing infestation by cabbage whiteflies ranged from 50% in G-type B. vulgaris and 8.3% in B. verna to no infestation at all in B. rupicola and P-type B. vulgaris. On the other hand, 95.8% of P-type plants showed symptoms of powdery mildew, Erysiphe cruciferarum Opiz ex L. Junell (Erysiphales: Erysiphaceae), while the G type and the other Barbarea spp. were unaffected by this pathogen. Additionally, the G and P types were used in two-choice oviposition preference tests to compare their attractiveness to the small white butterfly Pieris rapae L. (Lepidoptera: Pieridae). No significant differences in total oviposition per plant were found between the two types, but within-plant differences show that the small white butterfly prefers to oviposit on the adaxial leaf side in the P type. This study indicates that in locations where the cabbage whitefly is an economic pest, B. verna, which can also be used as a dead-end trap crop for the diamondback moth, could be chosen over G-type B. vulgaris.

Reducing insecticide use in winter oilseed rape by in-field to landscape-scale agroecological pest management

Reducing insect pest damage in field crops while minimizing insecticide use poses a significant challenge for farmers in Europe. Initiated in 2019, the six-year territorial project R2D2 aimed to explore the effectiveness of an agroecological crop protection approach in the context of widespread resistance of winter oilseed rape (WOSR) autumn beetles to pyrethroid insecticides. Over an area of 1371 hectares, ten farmers collectively developed a generative experimentation based on modifying cultural practices and implementing conservation biological control to gradually phase out insecticide use. Two years later, these farmers had made significant shifts in their pest management strategies by implementing a coordinated array of pest control measures from the field to the landscape level. These changes led to a complete cessation of systematic insecticide applications on WOSR and a 37% reduction in the insecticide Treatment Frequency Index (TFI) for this crop. Despite these promising outcomes, the total TFI across all crops, as assessed at the territorial level, remained unchanged. One of the main reasons for this is the increase in aerial insecticide applications on winter barley following the ban on neonicotinoids, as well as on spring pea to combat rising pea beetle pressures across the territory. For these two crops, effective alternatives to insecticides must be identified. More time is needed to instigate fundamental changes in farming systems and to enhance natural pest regulation through conservation biological control. Farmers’ support strategy should focus on identifying and overcoming barriers to the implementation of transformative systems.

Seasonal activity of Trechnites insidiosus (Hymenoptera: Encyrtidae) and its host Cacopsylla pyricola (Hemiptera: Psyllidae) in pear.

Cacopsylla pyricola (Förster) (Hemiptera: Psyllidae) is the most expensive and challenging insect pest of commercial pear trees in the Pacific Northwest. Integrated pest management (IPM) programs are working toward relying more heavily on natural enemies to reduce insecticide use. Trechnites insidiosus (Crawford) (Hymenoptera: Encyrtidae) is the main parasitoid of C. pyricola, but little is known about its biology in the region. Developing sampling tools is important for the deployment of IPM programs, including monitoring of natural enemies. In this study, we examined 2 conventional monitoring methods: beat trays and yellow sticky cards, in addition to screened sticky cards and 3D-printed cylinder traps. Additionally, we tested an overwintering trap for the collection of parasitized C. pyricola. The trapping methods were tested in orchards in Oregon and Washington. Unscreened cards caught the most T. insidiosus and C. pyricola, followed by screened cards, cylinder traps, and then beat trays. Beat trays sometimes failed to catch any T. insidiosus, even when it was found in abundance via other methods. Screened cards and cylinder traps reduced bycatch and increased ease of identifying T. insidiosus. Specimens from the cylinder traps were also more suitable for use in molecular analysis. The overwintering traps were effective at capturing parasitized C. pyricola, but were highly variable year to year. The ideal trapping method will vary based on research needs (e.g., DNA preservation, reducing bycatch, catching higher numbers), but both screened sticky cards and cylinder traps were viable methods for monitoring T. insidiosus and its host.

Biological Control as Part of the Soybean Integrated Pest Management (IPM): Potential and Challenges

Soybean production is usually performed on large scales, requiring simple but efficient pest management to be successful. Soybean fields are inhabited by several species of arthropods, demanding constant development of management practices to prevent pest outbreaks. More recently, stink bugs have become the most important pest group of soybeans in the Neotropics, responsible for up to 60% of the applied insecticides in Brazil. Natural enemies represent an important mortality factor that can keep the damage caused by stink bugs below the economic threshold levels without additional control actions. Thus, Conservation Biological Control (CBC) strategies can be adopted to preserve or even promote the increase in such natural enemies in the fields, or alternatively, massive releases of biocontrol agents in Augmentative Biological Control (ABC) programs could be adopted. Simple practices such as reducing insecticide use (with the adoption of economic thresholds), prioritizing harmless insecticides or biopesticides, and planting resistant soybean cultivars have been adopted in Brazil with positive results. The challenges to increasing the adoption of more complex stink bug management in commodity crops such as soybean may be overcome using the more recent economic incentives in the global agenda of decarbonized agriculture. The potential and challenges of conservation and augmentative biological control are further discussed in this review.

Predicting crop injury caused by flea beetles in spring oilseed rape through pest monitoring in the autumn

Abstract Reliably predicting pest damage would allow farmers to reduce insecticide use without incurring economic losses and thus contribute to agricultural sustainability. However, means to predict pest severity are lacking. We assessed whether crop feeding injury caused by flea beetles in spring oilseed rape can be predicted from flea beetle pest densities in the previous season using 22 years of suction trap catches of flea beetles in combination with crop feeding injury data from 293 fields. We found a strong positive relationship between the densities of flea beetles of the genus Phyllotreta in the summer and autumn activity period of the previous year and crop feeding injury caused by flea beetles in spring oilseed rape the following year. Autumn weather or the total cover of spring oilseed rape in the study region did not improve the prediction further. Pest monitoring using suction traps is thus a promising tool to predict crop feeding injury and can reduce insecticide use in years with low pest pressures.

Blueberries infected with the fungal pathogen Colletotrichum fioriniae release odors that repel Drosophila suzukii.

Spotted-wing drosophila, Drosophila suzukii, is a serious pest of thin-skinned fruits. Alternative methods to control this pest are needed to reduce insecticide use, including new repellents. Previous research demonstrated that D. suzukii adults use odor cues to avoid blueberries infected with the fungal pathogen Colletotrichum fioriniae, which causes the disease anthracnose. To identify novel D. suzukii repellents, we investigated the volatile emission from experimentally-infected fruit, which were inoculated with C. fioriniae isolates in the laboratory, and from field-collected fruit, which were naturally infected and harvested from a field. We then tested the pathogen-induced volatiles on D. suzukii adult behavior. Volatile emission was similar between all five C. fioriniae strains, with good agreement between experimentally-infected and field-collected berries. In total, 14 volatiles were found to be more abundant in infected versus uninfected fruit headspace. In multiple-choice bioassays, nine of the 14 volatiles elicited repellency responses from adult D. suzukii. These nine volatiles were further evaluated in dual choice assays, where all nine reduced fly capture by 43-96% compared to the control. The most repellent compounds tested were the esters ethyl butanoate and ethyl (E)-but-2-enoate, which were more or equally repellent to the known D. suzukii repellents 1-octen-3-ol, geosmin, and 2-pentylfuran. Dose-response assays identified concentration-dependent effects on D. suzukii repellency and oviposition when applied individually and consistent aversion observed across doses of a 1:1 blend. We report two repellents from C. fioriniae-infected blueberries that could be useful semiochemicals for the behavioral manipulation of D. suzukii in the field. © 2023 Society of Chemical Industry. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.

Mapping Aedes aegypti indoor resting behavior reveals a preference vulnerable to householder-led vector control.

Many mosquito vectors rest inside human habitations, a behavioral trait that is exploited for vector control by indoor residual spraying (IRS) of interior walls with insecticide. Although IRS and its refined version targeted IRS are very effective against Aedes aegypti, they are expensive and logistically challenging to deliver in densely populated urban areas where outbreaks of dengue and other arboviruses are the greatest challenge. In experiments in Recife, Brazil, we set out to quantify the indoor resting behavior of Ae. aegypti at a level beyond that previously reported. We found that significantly more Ae. aegypti males, unfed and fed females visited the base of walls (height 0-20 cm, corresponding to 12.3% of the total wall surface) more frequently than upper wall areas, with the difference more pronounced at higher temperatures. When the lowest 20 cm of the walls was treated with an appropriate insecticide and colored black, we recorded up to 85% cumulative mortality after 24-h exposure in the experimental room. The findings are significant because feasibly, householders could treat this small and accessible target zone manually, without the need for visits by costly IRS teams or equipment, reducing insecticide use and enabling communities to actively protect their own indoor environment.

Evaluating combined effects of pesticide and crop nutrition (with N, P, K and Si) on weevil damage in East African Highland Bananas.

Banana weevil (Cosmopolites sordidus, Germar) is a major pest in East African Highland Banana. The influence of crop nutritional status on weevil damage is poorly understood. Nutrient availability affects the nutritional quality of plants for weevils and may affect weevil damage. Here, we evaluate the effect of insecticides alone and in combination with fertilisers (N, P, K and Si) on weevil damage using data from two experiments in central and southwest Uganda. In the first experiment, we varied chlorpyrifos and application rates of N, P and K. In the second experiment, we varied the application rates of K and Si. Treatment effects were analysed using generalised linear mixed models with a negative binomial distribution. In the first experiment, chlorpyrifos reduced and N increased weevil damage, while P and K had no significant effect. In the K or Si application rates reduced weevil damage compared with the control. We conclude that the combined application of chlorpyrifos with K and Si fertilisers can contribute to weevil damage control on sites with low nutrient availability and should form part of integrated weevil management in bananas. Future studies should assess how much reduction in insecticide use is possible in EAHB with judicious input rates.

Dynamic Economic Thresholds for Insecticide Applications Against Agricultural Pests: Importance of Pest and Natural Enemy Migration.

In Integrated Pest Management programs, insecticides are applied to agricultural crops when pest densities exceed a predetermined economic threshold. Under conditions of high natural enemy density, however, the economic threshold can be increased, allowing for fewer insecticide applications. These adjustments, called 'dynamic thresholds', allow farmers to exploit existing biological control interactions without economic loss. Further, the ability of natural enemies to disperse from, and subsequently immigrate into, insecticide-sprayed areas can affect their biological control potential. We develop a theoretical approach to incorporate both pest and natural enemy movement across field borders into dynamic thresholds and explore how these affect insecticide applications and farmer incomes. Our model follows a pest and its specialist natural enemy over one growing season. An insecticide that targets the pest also induces mortality of the natural enemy, both via direct toxicity and reduced resource pest densities. Pest and natural enemy populations recover after spraying through within-field reproduction and by immigration from neighboring unsprayed areas. The number of insecticide applications and per-season farmer revenues are calculated for economic thresholds that are either fixed (ignoring natural enemy densities) or dynamic (incorporating them). The model predicts that using dynamic thresholds always leads to reduced insecticide application. The benefit of dynamic thresholds in reducing insecticide use is highest when natural enemies rapidly recolonize sprayed areas, and when insecticide efficacy is low. We discuss real-life situations in which monitoring of natural enemies would substantially reduce insecticide use and other scenarios where the presence of beneficial organisms may lead to threshold modifications.

Field, semi‐field and greenhouse testing of HOOK SWD, a SPLAT‐based attract‐and‐kill formulation to manage spotted‐wing drosophila

AbstractNative to Southeast Asia, the spotted‐wing drosophila (Drosophila suzukii) has become a major pest of small fruit crops in the Americas and Europe because females can oviposit in ripening fruit. Currently, D. suzukii management relies heavily on chemical control; thus, more sustainable approaches like attract‐and‐kill need to be evaluated to reduce insecticide use. In previous studies, HOOK SWD, an attract‐and‐kill product that combines attractants, phagostimulants and an insecticide (spinosad), showed promise for D. suzukii control; still, little is known about its performance under field conditions and under varying pest and host‐fruit densities, as well as its residual activity. Here, we evaluated the efficacy of HOOK SWD when applied in commercial blueberry farms, when deployed in semifield cages under different D. suzukii adult and fruit densities and when aged for 30 days in the greenhouse. Results from field experiments showed that HOOK SWD could reduce fruit infestation in blueberry farms; however, its efficacy varied in space and time. Semifield cage studies revealed that relatively high densities of both D. suzukii adults and fruit can reduce the effectiveness of HOOK SWD, which might explain the variation in its efficacy in the field. Ageing HOOK SWD in a greenhouse for at least 30 days yielded no significant decrease in insecticidal activity. Altogether, these studies show that HOOK SWD can potentially suppress D. suzukii populations in the field, but it should be used as part of an integrated pest management program instead of a stand‐alone control tool, especially under high pest and fruit densities.

Exclusion and Repulsion of Popillia japonica (Coleoptera: Scarabaeidae) Using Selected Coverings on High Tunnel Structures for Primocane Red Raspberry.

Simple SummaryThe Japanese beetle, Popillia japonica Newman, has become an invasive pest of increasing concern for several high-value berry crops in the Midwest region of the U.S. since 2010. Due to the feeding injury caused by adult beetles, many producers have increased their use of foliar insecticides to manage P. japonica. With a goal to develop sustainable Integrated Pest Management (IPM) systems for raspberry production, we initiated a 3-year study to examine the potential for various high-tunnel production systems to suppress P. japonica populations, and thus minimize insecticide use in primocane (autumn maturing) raspberry. During each year of the study, we observed significant reductions in P. japonica beetle infestations (p < 0.05), under the high-tunnel, covered systems, compared to nearby open plots of raspberry.In temperate climates, there has been an increasing interest by fruit growers to implement the use of high tunnels, using a variety of coverings, to extend the season for fruit production. High tunnels also provide an opportunity to enhance insect pest management, via physical exclusion, and thus support reductions in insecticide use. Due to increasing pest pressure by the Japanese beetle, Popillia japonica Newman, in Midwest U.S. raspberry, a 3-year study (2017–2019) was conducted to evaluate the efficacy of selected high tunnel coverings to suppress adult beetle populations and minimize adult feeding injury. During each year of the study, P. japonica adult beetles were significantly reduced under poly-based coverings, with the ends open, and when a fine, nylon-mesh was used to cover the ends (p < 0.05). The poly-based covering also resulted in moderately higher ambient temperatures, which may have influenced beetle movement, including a “repellency effect” that encouraged beetles to exit the high tunnel structures. Although P. japonica adults are known to feed on raspberry flower clusters, including fruit, the majority (73–92%) of beetle feeding in this study was observed on the foliage. The impact of high tunnels on P. japonica are discussed within the context of developing sustainable Integrated Pest Management (IPM) programs for raspberry production.

Regional pest suppression associated with adoption of Cry1Ac soybean benefits pest management in tropical agriculture.

Bacillus thuringiensis (Bt) crops have been adopted worldwide, providing high-level protection from insect pests. Furthermore, Bt crops preserve natural enemies, promote higher yield, and economically benefit farmers. Although regional pest suppression by widespread Bt crop adoption has been observed in temperate regions, this possibility remains uncertain in tropical areas due to the high diversity of alternative hosts and mild winters. Evidence of regional reduction in insecticide use across areas was observed in Brazil where Cry1Ac soybean has been grown since 2013, with up to 50% reduction in the number of insecticide sprays for managing lepidopteran pests on non-Bt soybean observed at specific locations from 2012 to 2019. Pest monitoring data from four mesoregions across 5 years of commercial plantings of Cry1Ac soybean from December 2014 to July 2019 showed reduced numbers of Chrysodeixis includens moths captured in pheromone traps across years at all locations. The number of Helicoverpa spp. moths captured also was reduced at three locations. We provide evidence for regional suppression of lepidopteran pests and reduced insecticide use with the widespread adoption of Cry1Ac soybean in Brazil, bringing economic, social and environmental benefits. © 2022 Society of Chemical Industry.

The sterile insect technique: an international framework to facilitate transboundary shipments of sterile insects

The sterile insect technique (SIT) has been successfully used since the 1950s as part of an integrated pest management approach in large-scale programmes to prevent, contain, suppress and eradicate key insect pests in many countries throughout the world. During this period, over one trillion live sterile insects have been shipped across borders. The very few adverse incidents from this significant trade were managed and resulted in no significant impacts. The phytosanitary and zoosanitary requirements by importing countries have been simple, facilitating the transboundary shipment of sterile insects, which is carried out mostly under the framework of cooperative agreements between the governments of the countries involved, and under technical cooperation projects of the United Nations. However, the shipment of sterile insects from sources outside this governmental framework, including public-private facilities, has been complicated, despite the availability of harmonised international guidelines in some cases, such as those for fruit flies. The SIT has great potential for the control of endemic pests or against the growing threat of invasive pests that can affect whole regions and even continents. Since SIT is species-specific, with negligible risk of introducing unwanted invasive species to the environment, and with the advantage of reducing insecticide use, a harmonised framework that recognises the low risk of SIT would facilitate shipments of sterile insects across borders and help to expand the use of this effective and environmentally friendly technology. The scope of this paper is limited to insects that have been sterilised using ionising radiation.

A major-effect genetic locus, ApRVII, controlling resistance against both adapted and non-adapted aphid biotypes in pea.

A genome-wide association study for pea resistance against a pea-adapted biotype and a non-adapted biotype of the aphid, Acyrthosiphon pisum, identified a genomic region conferring resistance to both biotypes. In a context of reduced insecticide use, the development of cultivars resistant to insect pests is crucial for an integrated pest management. Pea (Pisum sativum) is a crop of major importance among cultivated legumes, for the supply of dietary proteins and nitrogen in low-input cropping systems. However, yields of the pea crop have become unstable due to plant parasites. The pea aphid (Acyrthosiphon pisum) is an insect pest species forming a complex of biotypes, each one adapted to feed on one or a few related legume species. This study aimed to identify resistance to A. pisum and the underlying genetic determinism by examining a collection of 240 pea genotypes. The collection was screened against a pea-adapted biotype and a non-adapted biotype of A. pisum to characterize their resistant phenotype. Partial resistance was observed in some pea genotypes exposed to the pea-adapted biotype. Many pea genotypes were completely resistant to non-adapted biotype, but some exhibited partial susceptibility. A genome-wide association study, using pea exome-capture sequencing data, enabled the identification of the major-effect quantitative trait locus ApRVII on the chromosome 7. ApRVII includes linkage disequilibrium blocks significantly associated with resistance to one or both of the two aphid biotypes studied. Finally, we identified candidate genes underlying ApRVII that are potentially involved in plant-aphid interactions and marker haplotypes linked with aphid resistance. This study sets the ground for the functional characterization of molecular pathways involved in pea defence to the aphids but also is a step forward for breeding aphid-resistant cultivars.

Trophic attractiveness for soil fauna of residues of Bt and near-isogenic maize: a C and N stable isotope-based study

Genetically modified (GM) crops are considered a good way to reduce insecticide use and the presence of certain agricultural pests, thus improving food and environmental safety. Nevertheless, effects of GM plant residues on the soil food web are still poorly understood. Zea mays L., enriched with a gene from Bacillus thuringiensis Berliner subsp. kurstaki (Bt) as a defence against the maize borer, is widely cultivated. In this study, we explored the invertebrate food webs associated with residues of Bt and non-Bt maize, respectively represented by DKC6575, with a Cry1Ab transgene (event MON810), and its near-isogenic Tietar variety, in a five-month field experiment. C and N stable isotopes and Bayesian mixing models were used to assess trophic niche metrics and track nutrient flows from maize residues and weeds occurring in maize crops to invertebrate detritivores and predators. While there were no initial differences in the structural components of maize residues between varieties, after five months of exposure in the field, the lignin content was higher and the organic matter content was lower in non-Bt than in Bt maize. Organic matter depletion over time was associated with a decrease in primary consumer abundance and an increase in their trophic niche width in both Bt and non-Bt maize, but it was faster in the former. The abundance of primary consumers and predators was higher in non-Bt than in Bt maize, but the distribution of organisms across trophic levels differed between varieties, with prey availability being lower in non-Bt than in Bt maize. This allowed Bt-associated predators to maintain a diet based primarily on the maize food chain throughout the experimental period. In contrast, non-Bt-associated predators were more dependent on weed-feeding prey by the end of the experiment, increasing the coupling between the maize and weed energy channels in the soil food web. Some taxon-specific effects were evident. Less vagile organisms such as Diptera had a specific diet mostly related to maize regardless of variety and time, while the diets of more vagile organisms like Coleoptera and Opiliones changed the most over time. Overall, our results suggest that the attractiveness of non-Bt maize residues for invertebrate consumers is higher than the Bt variety, although the higher recalcitrant content following decomposition reduces it over time. The attractiveness also affects the movement of invertebrate predators (potentially including pest control agents) and thus nutrient flows in tri-trophic detritus-based food webs in cultivated and uncultivated plots.

Integrated pest management strategies for cabbage stem flea beetle (Psylliodes chrysocephala) in oilseed rape.

Oilseed rape (OSR) is the second largest source of vegetable oil globally and the most important biofuel feedstock in the European Union (EU) but the production of this important crop is threatened by a small insect, Psylliodes chrysocephala – the cabbage stem flea beetle (CSFB). The EU ban on use of neonicotinoid seed treatments and resistance of CSFB to pyrethroid insecticides have left farmers with limited control options resulting in drastic reductions in production. Integrated pest management (IPM) may offer a solution. We review the lifecycle of CSFB and the current options available, or in the research pipeline, for the eight IPM principles of the EU Sustainable Use of Pesticides Directive (Directive‐2009/128/EC). A full IPM strategy for CSFB barely exists. Although there are a range of preventative measures, these require scientific validation; critically, resistant/tolerant OSR cultivars are not yet available. Existing monitoring methods are time‐consuming and there are no commercial models to enable decision support based on predictions of migration timing or population size. Available thresholds are not based on physiological tolerances of the plant making it hard to adapt them to changing market prices for the crop and costs of control. Non‐synthetic alternatives tested and registered for use against CSFB are lacking, making resistance management impossible. CSFB control is therefore dependent upon conservation biocontrol. Natural enemies of CSFB are present, but quantification of their effects is needed and habitat management strategies to exploit their potential. Although some EU countries have local initiatives to reduce insecticide use and encourage use of ‘greener’ alternatives, there is no formal process for ranking these and little information available to help farmers make choices. We summarize the main knowledge gaps and future research needed to improve measures for CSFB control and to facilitate development of a full IPM strategy for this pest and sustainable oilseeds production.

Impact of Cotton Development Programme on Adoption of Recommended Bt Cotton Cultivation Practices

The study assessed the impact of Cotton Development Programme (CDP) on the adoption of recommended management practices in Bt-cotton (Gossypium hirsutum L). The data was collected from 210 farmers over a period of six years to make quantitative comparison with baseline data collected during the initial three year period (2013-15) from Mansa district of Punjab. The adoption of crop management practices in Bt-cotton in terms of recommended Bt-cotton hybrids, seed rate, fertilizer dose, use pattern of potassium nitrate (KNO3; 13:00:45) and reduction in insecticide use was investigated to quantify the impact of the CDP in the study region. These results revealed that area under recommended Bt cotton hybrids increased from a meager 15.2 per cent to as high as 89 per cent; adoption of recommended use nitrogenous fertilizers increased by 15.1 per cent; and the productivity of Bt-cotton enhanced by 138 per cent during this period. Therefore, it could be concluded that implementation of CDP was successful in the revival of Bt-cotton cultivation which was severely affected due to severe attack of sucking pests particularly by whitefly (Bemisia tabaci) during kharif-2015.