提前接种非致病尖孢镰刀菌防治西瓜枯萎病试验

将尖孢镰刀菌203株菌系接种在西瓜苗上,从中选出非致病尖孢镶刀菌系109个,分3个类群。用有促生作用,能在西瓜导管定殖的10个代表菌系提前接种,经温室和田间试验,结果表明316和317菌系的防病效果最好。在土壤含枯萎菌量2％条件下,推迟发病7～10天。在土壤含病菌量0.01％条件下,接种后25天,交叉保护防效分别为34.6％和68.2％。防病效果随枯萎菌量的下降而提高。

EFFECTS OF PRE-INOCULATION OF NON-PATHOGENIC FUSARIUM OXYSPORUM ON THE GROWTH OF FUSARIUM WILT ON WATERMELON

In the laboratory and greenhouse studies, 203 strains of Fusarium oxysporum collected from northern China were inoculated onto watermelon plants, and 109 of them were selected as non-pathogenic. These non-pathogenic strains were divided into three groups, i.e. stimulating, suppressing or no effect on the growth of watermelon plants. Ten strains representing the stimulating group, with high colonization frequences in vascular bundles of the plant, were pre-inoculated into the soil media before seeding watermelon in the greenhouse and field plots. The results showed that two strains, strain 316 and 317, (with challenge inoculum rate of 2% ) delayed the occurrence of Fusarium wilt symptoms by 7-10 days. When the challenge inoculum rate was 0.01%, the suppression effect on Fusarium wilt 25 days after the inoculation in the greenhouse tests was 34.6% and 68.2% for Strain 316 and Strain 317, respectively. This suppressing effect improved as the challenge inoculum rate decreased.