Dispersal of Phytophthora capsici and P-parasitica in furrow-irrigated rows of bell pepper, tomato and squash
Dispersal of Phytophthora capsici and P-parasitica in furrow-irrigated rows of bell pepper, tomato and squash
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DOI：
10.1111/j.1365-3059.1995.tb02661.x
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发表时间：
1995-12-01
期刊：
影响因子：
2.7
通讯作者：
Duniway, JM
中科院分区：
文献类型：
--
作者：
Cafe, AC;Duniway, JM
以3种一年生寄主作物为试验材料，研究了辣椒疫霉（Phytophthora capsici）和寄生疫霉（P.parasitica）在74 m长灌溉沟上端附近点源上的扩散规律。番茄旁边的犁沟接种辣椒疫霉或寄生疫霉，而辣椒和南瓜旁边的犁沟仅接种辣椒疫霉。灌溉以14天为一个周期进行。每种真菌在水中的传播通过在犁沟中的移植和沿沿着犁沟感染的番茄果实的发病率来监测。测定了各寄主根、茎上的病害梯度。重复灌溉将辣椒疫霉和寄生疫霉分散到距源70 m处。果实感染增加下游距离的增加，这表明积累的二次接种物与水的重复流动。相反，番茄和辣椒根部的病害严重程度梯度在源头达到峰值，并迅速下降到下游32米的低水平。水果和根感染上游来源是可以忽略不计的。南瓜的根和冠腐病是高度可变的，在某些单位中仅限于初始接种物附近的位置，而在其他单位中则发展到下游数米处的严重水平。与其他寄主不同，南瓜叶柄与灌溉水接触，可能是辣椒疫霉入侵的途径。运输接种物从犁沟水的根是有限的。辣椒疫霉对番茄根部的致病力和番茄果实的七叶树腐烂病发病率均高于寄生疫霉。
Dispersal of Phytophthora a capsici and P. parasitica from point sources buried near the upper end of 74 m-long irrigation furrows was studied with three annual host crops. Furrows next to tomato were inoculated with either P. capsici or P. parasitica, while furrows next to pepper and squash were inoculated with P. capsici only. Irrigation was carried out on a 14-day cycle. Dispersal of each fungus in the water was monitored by transplants in the furrows and the incidence of infected tomato fruit along furrows. Disease gradients on roots and shoots of all hosts were also measured. Repeated irrigations dispersed P. capsici and P. parasitica up to 70 m from the source. Fruit infection increased with increasing distances downstream, suggesting an accumulation of secondary inoculum with the repeated flow of water. Conversely, gradients of disease severity on roots of tomato and pepper peaked al the source and rapidly decreased to low levels up to 32 m downstream. Fruit and root infection upstream from source was negligible. Root and crown rot in squash was highly variable, being confined to locations near the initial inoculum in some units while developing to severe levels several meters downstream in other units. Unlike the other hosts, squash petioles were in contact with the irrigation water and may have served as routes of invasion by P. capsici. Transport of inoculum from the furrow water to the roots was limited. P. capsici isolates were more virulent on tomato roots and caused a higher incidence of buckeye rot on tomato fruit than did isolates of P. parasitica.