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BACKGROUND: Habitat management such as field- or farm-level diversification can conserve arthropod natural enemies, enhance biological pest control and lower (or suspend) insecticide use in agricultural crops. These approaches however have been underexploited to manage the aphid Aphis gossypii in cotton cropping systems of Xinjiang, China. In this study, we investigated whether the presence of licorice (Glycyrrhiza uralensis) at the field edge benefits generalist predator abundance and aphid biological control in local cotton crops. RESULTS: Field trials during 2020 and 2021 showed that licorice strips enhanced the in-field abundance of generalist predators (primarily ladybeetles) 2.2–4.3 fold during early season, i.e. initial growth before A. gossypii peak infestation pressure. During peak outbreak conditions in July, treatment fields with licorice strips experienced a respective 17.5–61.2% lowered aphid density and 12.3–14.6-fold higher predator-to-aphid abundance ratio (PAR) than control fields. In late season (aphid decline phase) of either year, cotton fields with licorice strips also attained a respective 4.7–9.9 fold higher PAR. Exclusion cage assays quantitatively assessed predator-mediated A. gossypii biological control and the relative contribution of licorice strips. The biocontrol services index (BSI) was 2.8 times (2020) and 1.4 times (2021) higher at 5 m distances from the licorice strip as compared to control fields. CONCLUSION: Licorice strips in the immediate vicinity of cotton fields benefit generalist arthropod predators and improve aphid biological control throughout the cotton cropping season. These findings help to integrate habitat management within integrated pest management (IPM) frameworks in the biggest cotton production region of China. [ABSTRACT FROM AUTHOR]

Summary: China is the world's second‐largest maize producer and consumer. In recent years, the invasive fall armyworm Spodoptera frugiperda (J.E. Smith) has adversely affected maize productivity and compromised food security. To mitigate pest‐inflicted food shortages, China's Government issued biosafety certificates for two genetically modified (GM) Bt maize hybrids, Bt‐Cry1Ab DBN9936 and Bt‐Cry1Ab/Cry2Aj Ruifeng 125, in 2019. Here, we quantitatively assess the impact of both Bt maize hybrids on pest feeding damage, crop yield and food safety throughout China's maize belt. Without a need to resort to synthetic insecticides, Bt maize could mitigate lepidopteran pest pressure by 61.9–97.3%, avoid yield loss by 16.4–21.3% (range −11.9–99.2%) and lower mycotoxin contamination by 85.5–95.5% as compared to the prevailing non‐Bt hybrids. Yield loss avoidance varied considerably between experimental sites and years, as mediated by on‐site infestation pressure and pest identity. For either seed mixtures or block refuge arrangements, pest pressure was kept below established thresholds at 90% Bt maize coverage in Yunnan (where S. frugiperda was the dominant species) and 70% Bt maize coverage in other sites dominated by Helicoverpa armigera (Hübner) and Ostrinia furnacalis (Guenée). Drawing on experiences from other crop/pest systems, Bt maize in se can provide area‐wide pest management and thus, contribute to a progressive phase‐down of chemical pesticide use. Hence, when consciously paired with agroecological and biodiversity‐based measures, GM insecticidal crops can ensure food and nutrition security, contribute to the sustainable intensification of China's agriculture and reduce food systems' environmental footprint. [ABSTRACT FROM AUTHOR]

Summary: Genetically‐modified crops expressing Bacillus thuringiensis (Bt) proteins have been widely cultivated, permitting an effective non‐chemical control of major agricultural pests. While their establishment can enable an area‐wide suppression of polyphagous herbivores, no information is available on the impact of Bt crop abandonment in entire landscape matrices. Here, we detail a resurgence of the cosmopolitan bollworm Helicoverpa armigera following a contraction of Bt cotton area in dynamic agro‐landscapes over 2007–2019 in North China Plain. An 80% reduction in Bt cotton was mirrored in a 1.9‐fold increase of ambient H. armigera population levels, culminating in 1.5–2.1‐fold higher yield loss and a 2.0–4.4‐fold increase in pesticide use frequency in non‐Bt crops (i.e. maize, peanut, soybean). Our work unveils the fate of herbivorous insect populations following a progressive dis‐use of insecticidal crop cultivars, and hints at how tactically deployed Bt crops could be paired with agro‐ecological measures to mitigate the environmental footprint of crop production. [ABSTRACT FROM AUTHOR]

The Anthropocene is characterised by pervasive human‐inflicted impacts on a broad range of biota, including insects. In 2019, we reviewed scientific literature quantifying the prevalence and magnitude of insect declines in recent time. Here, drawing upon 40 additional long‐term studies, we add evidence that is consistent with our earlier review and some other reviews on the fate of insect populations globally. New data for Greenland, northern Africa, South America, eastern Asia and Australia complement studies from Europe and North America. Temporal trends in insect populations are now derived from 100 long‐term studies and refer mainly to the past three or four decades (median 33 years). Data from the 10 major insect taxonomic orders indicate that an average 37% of species are declining in numbers, while populations of 18% species are increasing; the latter taxa mainly involve agricultural herbivores and nuisance pests. Population changes are more pronounced among aquatic insect communities, where 42% of species are declining and 29% increasing. Such changes result in a decrease in biomass across taxa, except for Heteroptera. Changes in species richness and diversity indices are inconsistent and do not reflect intraspecific population changes over time. These trends are observed irrespective of taxon, geography or methodological approach, although a lack of long‐term monitoring records prevents a proper assessment for tropical regions. [ABSTRACT FROM AUTHOR]

BACKGROUND The plant bug Lygus pratensis Linnaeus is a widely distributed polyphagous herbivore that increasingly attains outbreak population levels on cotton in northwestern China. Although the sex pheromone of L. pratensis from the United Kingdom has been identified as hexyl butyrate, (E)‐2‐hexenyl butyrate and (E)‐4‐oxo‐2‐hexenal, at a ratio of 100:25:24, this volatile blend does not prove attractive to Chinese field populations. RESULTS: In this study, we identified and optimized the sex pheromone of L. pratensis strains from northwestern China. In coupled gas chromatography and electro‐antennogram detection (GC–EAD) assays, three compounds within whole‐body extracts of virgin L. pratensis females elicited antennal responses: hexyl butyrate, (E)‐2‐hexenyl butyrate and (E)‐4‐oxo‐2‐hexenal. In field trials, a 20:1:30 ratio blend was the most attractive to L. pratensis males. CONCLUSION: Traps baited with this synthetic pheromone blend present considerable advantages over traditional sweep‐net sampling for L. pratensis population monitoring. It can readily be incorporated into monitoring schemes and integrated pest management packages. [ABSTRACT FROM AUTHOR]

Cover crops offer environmental and agricultural benefits, but adoption remains low. Soybean growers have indicated that the adoption of rye as a winter cover crop would increase, if it was shown to offer suppression of a key soybean pest, the soybean aphid Aphis glycines., We performed an on-farm evaluation of two cropping systems utilized in organic production and reduced-herbicide input production. One system includes a rye cover crop, whereas the other does not., At six and five location-years in Minnesota, A. glycines and predator populations, respectively, were measured and compared between the systems with and without rye., The system with the rye cover crop significantly suppressed A. glycines populations on soybean at five of six location-years. Predators appeared to respond more to prey abundance than to plant diversity. An exposure analysis examining biological control potential revealed no differences between soybean with and without rye at any location-year., Insect control can be added to the multiple benefits of rye winter cover crops. [ABSTRACT FROM AUTHOR]

The parasitoid Binodoxys communis (Gahan) (Hymenoptera: Braconidae) is a candidate for release against the Asian soybean aphid, Aphis glycines Matsumura (Homoptera: Aphididae), in North America. Using a series of Y-tube olfactometer assays, we recorded responses of naïve and experienced B. communis females to odors from both target and non-target host plant complexes. The non-target host plant complexes included three aphid species native to North America [ Aphis monardae Oestlund, Aphis oestlundi Gillette, and Aphis asclepiadis (Fitch)] and one species presumed to be exotic to North America ( Aphis nerii Boyer de Fonscolombe), all on their respective host plants. We also investigated whether the parasitoid distinguishes between volatiles from soybean infested with A. glycines vs. those of uninfested plants. Volatiles from A. glycines-infested soybean plants and several non-target host plant complexes elicited a response in B. communis, which seemed to be reinforced through oviposition experience. Wasps with experience on a specific host plant complex increased their response to odors of this complex. Neither naïve nor experienced wasps, however, preferred odors from target vs. non-target host plant complexes in choice tests. Our data also indicate that B. communis is unable to distinguish between volatiles from infested vs. uninfested soybean plants. This study shows that B. communis females respond to a broad array of olfactory stimuli, exhibit low fidelity for any particular odor, and employ some behavioral plasticity in their response to volatile cues. We discuss implications of these results for establishment of B. communis and potential undesirable non-target effects associated with the release of this species in North America. [ABSTRACT FROM AUTHOR]