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BACKGROUND Nitrogen (N) is essential to crop yield improvement and it can change crops' ability to defend against herbivores. To maximize economic yield, a higher amount of N‐fertilizer is often applied than the minimum required. Azotobacter is a good alternative to reduce N fertilizer application. In this study, we studied the yield and secondary defensive chemicals of maize, as well as the response of the key maize insect pest, Mythimna separata, as fed on maize plants inoculated with Azotobacter chroococcum and cultivated at different N fertilizer rates (i.e. the control rate of nitrogen fertilizer (CR), 80%CR and 60%CR) from 2018 to 2019. RESULTS: A. chroococcum inoculation just positively increased yield production of maize at 80%CR. Moreover, reduced N‐fertilizer application and A. chroococcum inoculation had opposite impacts on the foliar contents of jasmonic acid (JA), isoleucine conjugate of JA (JA‐Ile) and DIMBOA in maize, and they both negatively decreased the pupation rate and fecundity, and positively increased the eclosion rate and approximate digestibility (AD) of M. separata (P < 0.05). Furthermore, reduced N‐fertilizer application negatively prolonged larval life‐span, and decreased pupal weight, relative growth rate (RGR), efficiency of conversion of ingested food (ECI) and efficiency of conversion of digested food (ECD) of M. separata even A. chroococcum inoculation had positive effects on these indexes of M. separata (P < 0.05). CONCLUSION: These results help in understanding of the effects of low‐level N‐fertilizer and A. chroococcum inoculation on maize production and maize resistance to insects. This will be conducive to the integrated control of agricultural pests. © 2020 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

BACKGROUND: Elevated CO2 can alter the leaf damage caused by insect herbivores. Frankliniella occidentalis (Pergande) is highly destructive invasive pest of crop production worldwide. To investigate how elevated CO2 affects F. occidentalis fed with Phaseolus vulgaris and, in particular, the interaction between plant defense and thrips anti‐defense, nutrient content and antioxidant enzyme activity of P. vulgaris were measured, as well as the detoxifying enzyme activity of adult thrips. RESULTS: Elevated CO2 increased the soluble sugar, soluble protein and free amino acid content in non thrip‐infested plants, and decreased superoxide dismutase (SOD) and peroxidase (POD) activity in these plants. Feeding thrips reduced the nutrient content in plants, and increased their SOD, catalase and POD activity. Variations in nutrient content and antioxidant enzyme activity in plants showed an opposite tendency over thrip feeding time. After feeding, acetylcholinesterase, carboxylesterase, and mixed‐function oxidase activity in thrips increased to counter the plant defenses. Greater thrip densities induced stronger plant defenses and, in turn, detoxifying enzyme levels in thrips increased over thrip numbers. CONCLUSION: Our study revealed that F. occidentalis can induce not only an antioxidant‐associated plant defense, but also detoxifying enzymes in thrips. Elevated CO2 might both enhance plant defense against thrip attack, and increase thrip anti‐defense against plant defenses. © 2018 Society of Chemical Industry Elevated CO2 alters the leaf damage and plant defense responses caused by insect herbivores. This article presents an analysis of antioxidant‐associated plant defense and detoxifying‐associated thrips anti‐defense. [ABSTRACT FROM AUTHOR]

BACKGROUND The approval of transgenic Bacillus thuringiensis ( Bt) rice by China was momentous for biotech crops, although it has yet to be approved for commercial production. Non-target pest problems in rice paddies, such as the three ecologically similar species of planthoppers Nilaparvata lugens, Laodelphax striatellus and Sogatella furcifera, could become increasingly serious under global climate change. Fused ( Cry1Ab/ Cry1Ac) and single ( Cry1Ab) transgenic Bt rice were evaluated for effects on species-specific responses of planthoppers to elevated carbon dioxide ( CO2) and temperature. RESULTS Transgenic Bt rice lines significantly modified species-specific responses of the planthoppers to elevated CO2 and temperature. High temperature appears to favour outbreaks of S. furcifera relative to N. lugens and L. striatellus when feeding upon fused transgenic Bt rice, especially at elevated CO2. Elevated CO2 at high temperature appears to be a factor reducing S. furcifera occurrence when feeding upon single transgenic Bt rice. CONCLUSION Different types of transgenic Bt rice alter the species-specific responses of non-target planthoppers to elevated CO2 and temperature. Compared with their non-transgenic parental lines, the single transgenic Bt rice shows better performance in controlling the non-target planthopper S. furcifera by comparison with the fused transgenic Bt rice under elevated CO2 and temperature. It is suggested that multitypes of transgenic Bt rice be used in the field simultaneously in order to take advantage of high transgenic diversity for optimal performance against all pests in paddy fields. © 2013 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Background: Elevated CO 2 can alter the leaf damage caused by insect herbivores. Frankliniella occidentalis (Pergande) is highly destructive invasive pest of crop production worldwide. To investigate how elevated CO 2 affects F. occidentalis fed with Phaseolus vulgaris and, in particular, the interaction between plant defense and thrips anti-defense, nutrient content and antioxidant enzyme activity of P. vulgaris were measured, as well as the detoxifying enzyme activity of adult thrips., Results: Elevated CO 2 increased the soluble sugar, soluble protein and free amino acid content in non thrip-infested plants, and decreased superoxide dismutase (SOD) and peroxidase (POD) activity in these plants. Feeding thrips reduced the nutrient content in plants, and increased their SOD, catalase and POD activity. Variations in nutrient content and antioxidant enzyme activity in plants showed an opposite tendency over thrip feeding time. After feeding, acetylcholinesterase, carboxylesterase, and mixed-function oxidase activity in thrips increased to counter the plant defenses. Greater thrip densities induced stronger plant defenses and, in turn, detoxifying enzyme levels in thrips increased over thrip numbers., Conclusion: Our study revealed that F. occidentalis can induce not only an antioxidant-associated plant defense, but also detoxifying enzymes in thrips. Elevated CO 2 might both enhance plant defense against thrip attack, and increase thrip anti-defense against plant defenses. © 2018 Society of Chemical Industry., (© 2018 Society of Chemical Industry.)

Background: Chilo suppressalis is an important lepidopteran rice pest in the rice-growing areas of China, and the development of transgenic rice expressing the Cry1C insecticidal protein has provided a useful strategy for controlling this pest. However, insect resistance is a major threat to the durability of cry1C rice. Thus, evaluation of the risk of insect resistance before the commercial use of cry1C rice is crucial., Results: This study investigated the development of C. suppressalis resistance to Cry1C protein and the relative fitness of Cry1C-resistant and -susceptible strains on different Bt rice lines. The LC 50 value of the Cry1C-resistant strain increased 42.6-fold after 41 generations of selection, and the estimated realized heritability (h 2 ) of Cry1C resistance was 0.096 in C. suppressalis. Moreover, the Cry1C-resistant strain displayed high fitness on the cry1C line, but not on the cry1Ab and cry1Ab + cry1C lines and was not cross-resistant to Cry1Ab., Conclusions: These findings suggest that C. suppressalis has the potential to develop resistance to Cry1C, although the rate of evolution is low. The pyramiding of the cry1A and cry1C genes in Bt rice is an effective strategy for delaying the evolution of resistance in C. suppressalis and sustainably maintaining the utility of Bt rice. © 2017 Society of Chemical Industry., (© 2017 Society of Chemical Industry.)