Anco D J, Madden L V, Ellis M A
The Ohio State University, Department of Plant Pathology, Ohio Agricultural Research and Development Center, Wooster 44691.
Plant Dis. 2012 Sep;96(9):1297-1302. doi: 10.1094/PDIS-09-11-0806-RE.
Phomopsis cane and leaf spot on Vitis spp. (grape) is currently understood to be monocyclic, with primary inoculum only being produced early in the growing season. However, of the few published studies pertaining to sporulation of Phomopsis viticola, none specifically examined rachises, and none were designed to determine when infected tissues become capable of sporulation. The objective of these studies was to determine when grape shoots, canes, and rachises infected with P. viticola develop the capacity to sporulate, and to determine the time period during which those tissues remain capable of sporulation. Starting in 2009 and 2010, infected first-year shoots and rachises were collected biweekly throughout the growing season, into the dormant season, and into the following growing season. Tissues were collected from 'Catawba,' 'Concord,' and 'Reliance' vineyards. Samples were observed for sporulation after 48 h of incubation in a moist chamber at 23°C; the magnitude of the conidia production under these optimal conditions was considered the sporulation potential. For infections that occurred in 2009 and 2010, the production of conidia was not observed until after harvest. In the year following infection, sporulation potential was found from about bud break until shortly after the end of bloom. There was a generally consistent temporal pattern to relative sporulation potential across sampled vineyards, years, and grape tissues (rachises and canes), described by a modified β model, with peak sporulation potential occurring around 16 May. These results confirmed that Phomopsis cane and leaf spot is a monocyclic disease and support control recommendations for use of fungicides in spring.
葡萄上的拟茎点霉枝蔓和叶斑病目前被认为是单循环病害，其初侵染接种体仅在生长季早期产生。然而，在已发表的关于葡萄生拟茎点霉产孢的少数研究中，没有一项专门研究过果穗轴，也没有一项旨在确定受感染组织何时开始具备产孢能力。这些研究的目的是确定感染葡萄生拟茎点霉的葡萄新梢、枝蔓和果穗轴何时开始具备产孢能力，并确定这些组织保持产孢能力的时间段。从2009年和2010年开始，在整个生长季、进入休眠季以及次年生长季，每隔两周采集受感染的一年生新梢和果穗轴。样本取自“卡托巴”“康科德”和“信赖”葡萄园。将样本在23°C的保湿箱中培养48小时后观察其产孢情况；在这些最佳条件下分生孢子的产生量被视为产孢潜力。对于2009年和2010年发生的感染，直到收获后才观察到分生孢子的产生。在感染后的次年，从大约萌芽期到花期结束后不久都能发现产孢潜力。在采样的葡萄园、年份和葡萄组织（果穗轴和枝蔓）中，相对产孢潜力存在大致一致的时间模式，可用修正的β模型描述，产孢潜力峰值出现在5月16日左右。这些结果证实了葡萄拟茎点霉枝蔓和叶斑病是一种单循环病害，并支持在春季使用杀菌剂的防治建议。
