Abstract

The interaction between the stem and bulb nematode, Ditylenchus dipsaci, and the causal agent of basal rot of garlic, Fusarium oxysporum f. sp. cepae (Foc), was studied in controlled environment trials. Inoculations with individual pathogens, simultaneous inoculation, and sequential inoculations (one pathogen applied 7 d before the second pathogen) were investigated for effects on disease severity and plant growth. All treatments resulted in shorter plants, and reduced shoot and bulb fresh weight, compared with untreated control plants. Plants receiving simultaneous inoculation and sequential inoculation with D. dipsaci first had greater disease incidence and foliar disease severity than plants receiving single inoculations of either pathogen. Disease severity in the bulb was greatest for simultaneous inoculation and D. dipsaci applied alone. The sequential inoculation with Foc applied first resulted in lower disease severity on the bulbs than when Foc was applied alone. The stem and bulb nematode populations in the soil and plant tissue and the nematode reproduction factor (RF) showed the same pattern of response as bulb severity. Plants receiving nematodes only had the highest number of nematodes and highest RF. The lowest RF was found when Foc was first applied in sequential inoculation treatments. The interaction of D. dipsaci and the isolation of Foc used in this study resulted in less severe disease in the bulb and lower nematode populations than when the garlic plants were inoculated with D. dipsaci alone.

摘要

茎和鳞茎线虫Ditylenchus dipsaci与大蒜基腐病病原体Fusarium oxysporum f之间的相互作用。sp. cepae (Foc)，在受控环境试验中进行了研究。研究了单个病原体的接种、同时接种和顺序接种（一种病原体在第二种病原体之前 7 天应用）对疾病严重程度和植物生长的影响。与未处理的对照植物相比，所有处理都导致植株更短，茎和球茎鲜重降低。接受同时接种和连续接种鳞球茎线虫的植物与接受任一病原体单次接种的植物相比，首先具有更高的发病率和叶面病害的严重程度。同时接种和单独应用鳞球茎球茎的病害严重程度最高。与单独应用 Foc 相比，首先应用 Foc 的顺序接种导致球茎上的疾病严重程度较低。土壤和植物组织中的茎和球茎线虫种群以及线虫繁殖因子 (RF) 显示出与球茎严重程度相同的响应模式。接受线虫的植物只有最高数量的线虫和最高的 RF。当 Foc 首次应用于连续接种处理时，发现了最低的 RF。球茎线虫的相互作用并用FOC的隔离在这项研究导致灯泡不太严重的疾病和较低的线虫人口超过当大蒜植株接种D.线虫孤单。