Morgan David P, Driever George F, Felts Dan, Krueger William H, Michailides Themis J
University of California, Department of Plant Pathology, University of California, Davis, Kearney Agricultural Center, Parlier 93648.
University of California, Cooperative Extension, Orland 95963.
Plant Dis. 2009 Nov;93(11):1175-1181. doi: 10.1094/PDIS-93-11-1175.
Two empirical models to predict infection events were evaluated for control of Botryosphaeria panicle and shoot blight, caused by a Fusicoccum sp., as well as the effectiveness of early-season fungicide sprays on the control of this disease of pistachio. A model incorporating wetness duration was superior to one based solely on duration of rains ≥1 mm/h for ≥4 h and with temperature ≥11°C. The wetness duration threshold (W) for rain events ≥4 mm at a given temperature (T) for high-risk infection events was W = -7.8 + 397/T and the threshold for medium-risk events was W = -6.9 + 220/T. Wet periods interrupted by ≤12 h were added together to calculate W. In two orchards with high levels of inoculum, one high-risk event resulted in 20 to 23% blighted fruit at harvest and two or three high-risk events resulted in 31 to 80% blighted fruit. Latent infections were 0 to 1% in instances where only low-risk events (one to two events) occurred prior to collection of pistachio fruit for determination of latent infections and were 17 to 36% with one to three high-risk events. Early-season fungicide sprays in April to May effectively controlled panicle and shoot blight when applied up to 12 days before predicted infection events or 5 days after.
评估了两种用于预测感染事件的经验模型，以控制由一种壳梭孢属真菌引起的葡萄座腔菌穗枯病和枝枯病，以及评估季初杀菌剂喷雾对控制开心果这种病害的效果。一个纳入湿度持续时间的模型优于仅基于降雨量≥1毫米/小时且持续时间≥4小时以及温度≥11°C的模型。在给定温度（T）下，对于高风险感染事件，降雨≥4毫米时的湿度持续时间阈值（W）为W = -7.8 + 397/T，中等风险事件的阈值为W = -6.9 + 220/T。被≤12小时打断的潮湿时段相加来计算W。在两个接种量高的果园中，一次高风险事件导致收获时20%至23%的果实枯萎，两到三次高风险事件导致31%至80%的果实枯萎。在采集开心果果实以测定潜伏感染之前，仅发生低风险事件（一到两次事件）的情况下，潜伏感染率为0%至1%，而发生一到三次高风险事件时，潜伏感染率为17%至36%。4月至5月的季初杀菌剂喷雾在预测感染事件前12天内或之后5天内施用时，能有效控制穗枯病和枝枯病。
