Abstract：
BACKGROUND: In order to improve the biological control agent (BCA) efficacy, stress factors threatening the viability of microorganisms during spray application need to be determined. The effect of spray mixture temperature and exposure time on Trichoderma harzianum T 22 and Bacillus amyloliquefaciens QST713 viability were tested. Concurrently the combined effect of mechanical and thermal stress effect on BCA viability were tested at two initial spray mixture temperatures (14 and 25 °C) by simulating a spray application using airblast sprayers featured by different tank capacity and a spray liquid circuit (without and with hydraulic agitation system). To assess the BCA microorganism viability, spray mixture samples were collected at time intervals along trials and plated to count the colony forming units (CFU).
RESULTS: The critical temperature threshold that inhibited BCA viability was 35 °C with 30 min of exposure. The sprayer type, the initial temperature of the spray mixture and the temperature increment during the trials significantly decreased the number of CFU recovered. When simulating a spray application, the spray mixture temperature increase rate was determined mainly by the residual amount of spray mixture in the tank. Even if the tank capacity does not substantially affect the final temperature reached by the spray mixture, the higher residual spray mixture in bigger tanks can expose the BCAs for a longer time to critical temperatures.
CONCLUSIONS: Experimental trials allowed us to identify the effect of factors affecting the viability of tested BCAs, providing information about the actual chance to guarantee the biological efficacy of BCA treatments. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
RESULTS: The critical temperature threshold that inhibited BCA viability was 35 °C with 30 min of exposure. The sprayer type, the initial temperature of the spray mixture and the temperature increment during the trials significantly decreased the number of CFU recovered. When simulating a spray application, the spray mixture temperature increase rate was determined mainly by the residual amount of spray mixture in the tank. Even if the tank capacity does not substantially affect the final temperature reached by the spray mixture, the higher residual spray mixture in bigger tanks can expose the BCAs for a longer time to critical temperatures.
CONCLUSIONS: Experimental trials allowed us to identify the effect of factors affecting the viability of tested BCAs, providing information about the actual chance to guarantee the biological efficacy of BCA treatments. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
摘要：
背景：为了提高生物防治剂（BCA）的功效，需要确定在喷雾施用期间威胁微生物生存力的应激因素。测试了喷雾混合物温度和暴露时间对哈茨木霉T22和解淀粉芽孢杆菌QST713活力的影响。同时，在两个初始喷雾混合物温度（14°C和25°C）下，通过模拟使用具有不同罐容量和喷雾液回路的鼓风喷雾器的喷雾应用，测试了机械和热应力对BCA生存力的综合影响（没有和有液压搅拌系统）。为了评估BCA微生物的生存能力，沿着试验以时间间隔收集喷雾混合物样品并铺板以计数菌落形成单位(CFU)。
结果：抑制BCA活力的临界温度阈值为35°C，暴露30分钟。喷雾器类型，喷雾混合物的初始温度和试验过程中的温度增量显着降低了回收的CFU的数量。当模拟喷雾应用时，喷雾混合物的升温速率主要取决于罐中喷雾混合物的残留量。即使罐容量基本上不影响喷雾混合物达到的最终温度，较大罐中较高的残余喷雾混合物可以将BCA暴露于临界温度更长的时间。
结论：实验试验允许确定影响测试BCA活力的因素的影响，提供有关保证BCA治疗生物学功效的实际机会的信息。本文受版权保护。保留所有权利。
结果：抑制BCA活力的临界温度阈值为35°C，暴露30分钟。喷雾器类型，喷雾混合物的初始温度和试验过程中的温度增量显着降低了回收的CFU的数量。当模拟喷雾应用时，喷雾混合物的升温速率主要取决于罐中喷雾混合物的残留量。即使罐容量基本上不影响喷雾混合物达到的最终温度，较大罐中较高的残余喷雾混合物可以将BCA暴露于临界温度更长的时间。
结论：实验试验允许确定影响测试BCA活力的因素的影响，提供有关保证BCA治疗生物学功效的实际机会的信息。本文受版权保护。保留所有权利。
