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【Objective】 Waterlogging and thermal stress are two abiotic stresses faced by cotton production in central China. This paper analyzed the spatiotemporal variation in waterlogging (WL), thermal stress (HT), and waterlogging followed by thermal stress (WL-HT) to cotton in Hubei province. 【Method】 Daily precipitation and air temperatures were collected from 26 meteorological stations across the province to calculate the occurrence of WL, HT, WL-HT, as well as the conversion from WL to WL-HT at the seedling, budding, flowering and boll-filling stage, and the boll opening stage. Spatiotemporal variations of these events were calculated using the linear temporal trend method, the moving t-test and the inverse distance interpolation. 【Result】 The last six decades have seen a significant increase in WL (p30%. Huanggang was prone to both WL and WL-HT. In contrast, Xiangyang, Zhongxiang and Jingzhou had a low WL but high WL-HT. 【Conclusion】 Cotton production in Hubei province has seen an increase in waterlogging followed by high temperatures over the recent decade. Timely drainage at the flowering and boll-filling stage when temperature is high in the south-central, northwestern and northeastern province is essential to safeguarding cotton production there.

BACKGROUND: Chemical control is the most used and effective method to control Diaphorina citri, the vector of the phloem‐limited bacteria associated with citrus huanglongbing (HLB) disease. The objectives of this study were to determine the effectiveness of flupyradifurone applied via dripping irrigation systems on D. citri. Bioassays were conducted using leaves harvested on various dates post treatment, and insecticide residue in leaf tissue was quantified. RESULTS: The drip application of flupyradifurone on citrus trees provided high‐level and long‐term control against D. citri adult, and the median lethal concentration (LC50) for ingestion of flupyradifurone in D. citri was 22.22 mg kg–1 (fresh leaf). Flupyradifurone residue was detected in leaf tissue within 3 days after treatment. The measured level of flupyradifurone peaked on day 40 day after application, and then showed a steady decline in subsequent days for all three applied dosages. The amounts of flupyradifurone in upper, middle, and lower leaves were similar, and trends in the change in concentration of flupyradifurone were consistent. CONCLUSIONS: The results demonstrate that flupyradifurone can be a valuable new tool for D. citri management programs, and drip‐applied flupyradifurone provides an extended period of control efficacy. This paper could provide a reference to reduce the dependence on foliar‐applied insecticides, with associated benefits for non‐target exposure to workers and pollinators. © 2021 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

BACKGROUND: Endogenous plant β‐glucosidases can be utilized to hydrolyze pro‐pesticides and release the bioactive pesticide. Two related glucose–fipronil conjugates with different linkers structure, N‐{3‐cyano‐1‐[2,6‐dichloro‐4‐(trifluoromethyl) phenyl]‐4‐[(trifluoromethyl) sulfinyl]‐1H‐pyrazol‐5‐yl}‐1‐(2‐triazolethyl‐β‐d‐glucopyranoside)‐1H‐1,2,3‐triazole‐4‐methanamine (GOTF) and N‐{3‐cyano‐1‐[2,6‐dichloro‐4‐(trifluoromethyl) phenyl]‐4‐[(trifluoromethyl)‐sulfinyl]‐1H‐pyrazol‐5‐yl}‐2‐aminoethyl‐β‐d‐glucopyranoside (GOF), were deglucolysated by β‐glucosidase both in vitro and in vivo at different rates. Here, the basis for these differences was investigated by revealing the kinetics of the reaction and by modeling molecular docking between enzyme and substrate. RESULTS: Results from kinetic study showed that the reaction rate was the main reason for the poorer rate of GOF hydrolysis with respect to GOTF. Modeling of substrate docking indicated that the spacer arm of glucose–fipronil conjugates affects the strength of non‐covalent bonds within the active site and the position of fipronil within the pocket. Four glucose–fipronil conjugates and four corresponding aglycones were synthesized, and the hydrolysis data confirmed that the increased tether length between the bulky aglycone and glycone would lead to faster hydrolysis rate. The bioassay results indicated that most glucose–fipronil conjugates displayed moderate to excellent insecticidal activities in vivo against Plutella xylostella larvae. CONCLUSION: This study provides a potential strategy to optimize the substrate structure to enhance hydrolytic specificity in order to design appropriate phloem mobile pro‐pesticides. © 2018 Society of Chemical Industry Plant endogenous β‐glucosidases can interact with exogenously applied pro‐pesticides to release a bioactive form of the pesticide. The study investigates the structure–activity relationship between the glucose–fipronil conjugates and β‐glucosidase. [ABSTRACT FROM AUTHOR]

Drought and flood abrupt alternations (DFAA) are new challenges under climate change with particular emphasis on its affects related to agriculture. However, current regional DFAA analysis research rarely investigates agricultural DFAA with special regards to agricultural elements. In this work, a method based on a daily scale index named the standardized antecedent precipitation evapotranspiration index (SAPEI) and crop characteristics was established to investigate the characteristics of agricultural DFAA during cotton growth stages in the middle-and-lower Yangtze River (MLRYR) during 1961–2020. Additionally, the influence of DFAA on cotton climatic yield in response to flooding and drought was examined by multiple regression. The results demonstrate that the SAPEI efficiently described the relations between cotton climatic yield and the intensities of cotton drought and flood and well characterized cotton DFAA events, especially for short-term events. The most recent decade over the past six decades has seen the most frequent cotton DFAA events, and the only significant trend (p < 0.05) of cotton DFAA frequency was an upward trend in Jiangsu Province. In addition, the middle growth stage of cotton was the most DFAA-affected period within a year. Cotton drought-flood alternations (DF) were more common than flood-drought alternations (FD). The most DF-prone and FD-prone regions differed greatly, but the northeastern MLRYR was the most DFAA-prone region. In all provinces, the cotton DFAA frequency was significantly and positively related to the cotton drought frequency. Finally, the relations between cotton climatic yield and the intensities of drought and flood were much less significant in the years with more DFAA events than in other years, indicating an obvious negative interaction between drought and flood in cotton DFAA events. This finding, at the regional scale, confirmed previous field-scale conclusions on cotton responses to DFAA stress. In summary, this work provides references for agricultural water management in adapting to climate change. • A method for assessing agricultural drought and flood abrupt alternation was proposed. • A near-term high risk of cotton drought and flood abrupt alternation was detected. • More droughts probably bring more agricultural drought and flood abrupt alternations. • Negative interaction between cotton drought and flood was found at a regional scale. [ABSTRACT FROM AUTHOR]