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[Objective] To explore the occurrence dynamics of pitaya soot disease and screen the control agents, and to provide a reference for the development of effective control strategies for pitaya soot disease. [Method] The five sampling points method was used and random sampling survey in 2018 - 2019 pitaya plant in different developmental stages period was conducted on tender tip, the bud, calyx, and expands fruit, fruit maturation and the parts of the soot disease occurrence, calculated the corresponding disease index, and recorded the temperature and humidity data, drew each part of the 2018 - 2019 pitaya plant soot disease occurrence dynamic graph. In order to screen out the suitable insecticides for the prevention and control of pitaya soot disease, five kinds of insecticides were carried out in the serious pitaya planting zone. [Result] The peak of soot disease on the young shoot of pitaya occurred in late April every year. The peak of bud soot disease occurred in the middle of April, the middle of July and the end of September. The peak of calyx soot disease occurred in late July, mid-August and late September every year. The peak of young fruit soot disease occurred in the middle of May, late July and late September. The peak of soot disease occurred in the middle of May, the middle of August and the middle of October. The peak of soot disease in mature fruits occurred in late July, mid-September and mid-October. The results of field control experiments showed that the control effects of 40% pyrimethanil suspension 750 times, 500. 0 g/L isobarbazone suspension 750 times, 440. 0 g/L metharazone · chlorothalonil suspension 750 times, 75% chlorothalonil wettable powder 600 times and 45 % diazonium water 750 times were above 70. 00%. [Conclusion] In Chongzuo and Nanning in Guangxi, from April to October in each year, early period in month is suitable for prevention and control of pitaya soot disease period, after repeated experiments, 40% pyrimethanil suspension 750 times, 500. 0 g/L isobarbazone suspension 750 times, 440. 0 g/L metharazone · chlorothalonil suspension 750 times liquids have over 70. 00% control effect on pitaya soot disease. These three agents are recommended for use in manufacturing. [ABSTRACT FROM AUTHOR]

A simple and efficient multiresidue method using dispersive solid phase extraction and liquid chromatography coupled with tandem mass spectrometry was developed for the targeted analysis of indaziflam and its five metabolites (indaziflam‐diaminotriazine, indaziflam‐carboxylic acid, indaziflam‐triazine indanone, indaziflam‐hydroxyethyl, and indaziflam‐olefin) in pitaya samples (including roots, plants, flowers, peels, pulp, and whole fruit). The analytes were extracted with acetonitrile, and the extracts were purified using multiwalled carbon nanotubes. The method was validated using pitaya samples spiked at 0.5, 5, and 50 µg/kg, and the average recoveries varied from 61.1 to 103.7% with relative standard deviations lower than 12.7% (n = 5). This method exhibited sufficient linearity within the concentration range of 0.1–100 µg/L. The limits of detection and quantification were in the ranges of 0.001–0.1 and 0.003–0.3 µg/kg, respectively. The method was successfully applied to analyze pitaya samples in Nanning, and no indaziflam or its metabolites were detected in the samples analyzed. [ABSTRACT FROM AUTHOR]