Isopyrazam is a new broad-spectrum, foliar-absorbed and -translocated succinate dehydrogenase inhibitor fungicide. In this study, 159 Botrytis cinerea isolates collected from different geographical regions of Shandong Province of China were characterized for baseline sensitivity to isopyrazam. Furthermore, the protective and curative activity of isopyrazam on strawberry fruit and the control efficacy in the field were also determined. In contrast to its mycelial growth, the spore germination of B. cinerea was inhibited completely by lower concentrations of isopyrazam, about 1 μg ml⁻¹ on yeast-peptone-acetate medium. Frequency distributions of isopyrazam 50% effective concentration (EC₅₀) values were unimodal curves, with mean EC₅₀ values of 0.07 ± 0.04 (standard deviation) and 0.68 ± 0.36 μg ml⁻¹ for the inhibition of spore germination and mycelial growth, respectively. In addition, there was no positive multiple resistance between isopyrazam and other classes of botryticides such as diethofencarb, iprodione, pyrimethanil, or SYP-Z048. In field trials conducted during 2014 and 2015, isopyrazam used at a concentration of active ingredient at 150 and 200 g ha⁻¹ provided a control efficacy ranging from 76.7 to 87.8% on leaves and from 81.5 to 90.7% on fruit. These results suggest that isopyrazam has the potential to play an important role in the management of gray mold.

Bt crops will face a new ecological risk of reduced effectiveness against target-insect pests owing to the general decrease in exogenous-toxin content in Bt crops grown under elevated CO ₂ . How to deal with this issue may affect the sustainability of transgenic crops as an effective pest management tool especially under future CO ₂ raising. In this study, azotobacters, as being one potential biological regulator to enhance crops’ nitrogen utilization efficiency, were selected and the effects of Bt maize and non- Bt maize infected by Azospirillum brasilense and Azotobacter chroococcum on development and food utilization of target Mythimna separate were studied under ambient and elevated CO ₂ . The results indicated that azotobacter infection significantly increased larval life-span, pupal duration, RCR and AD of M. separata , and significantly decreased RGR, ECD and ECI of M. separata fed on Bt maize; There were opposite trends in development and food utilization of M. separata fed on non- Bt maize infected with azotobacters compared with the buffer control regardless of CO ₂ level. Presumably, the application of azotobacter infection could make Bt maize facing lower field hazards from the target pest of M. separate , and finally improve the resistance of Bt maize against target lepidoptera pests especially under elevated CO ₂ . Summary statement: Elevated CO ₂ effect on development and food utilization of target armyworm Mythimna separata fed on Bt maize infected by azotobacter, Azospirillum brasilense and Azotobacter chroococcum