用木霉培养物防治温床蕃茄苗猝倒病

用玻璃纸对峙法测定了57株从西南四省区获得的木霉对蕃茄倒病原菌(Pythium sp.)拮抗作用。结果表明:有37株对 Pythium sp 有明显拮抗作用,占测定菌株的64.9%,其中又以 Trichoderma aureoviride、T.citrinoviride 和哈茨小霉(T.harzianum)居多。木霉对 Pythium sp 的拮抗作用主要表现为菌丝消解和断裂,与木霉对 Rhizoctonia solani 的拮抗现象明显不同。用一株对Pythium sp 有较强拮抗作用的哈茨木霉制成麦麸砂子培养物,防治温床育苗的蕃茄苗猝倒病获得满意的防效,与化学农药敌克松和五氯硝基苯的防效相当,甚至略优。酿热物温床有利于木霉的生长和营养物竞争作用,因此用木霉防治早春蔬菜温床育苗中猝倒病是很有希望的。

BIOCONTROL OF DAMPING-OFF OF TOMATO SEEDLINGS IN HOTBED WITH TRICHODERMA HARZIANUM

In ordcr to screen antagonistic Trichoderma,antagonistic effect of 57 isolates of Trichoderma against the pathogen of damping-off in tomato seeling was tested with dual culture method.37 isolates or them possessed obvious antagonism against pythium sp., amounting to 64.9 percent of the total tested isolates.Species aggregates of the antagenists were:T.harzianum,T.aurcoviride,T.citrinoviride,T.koninig(?),T.pseud(?)koningii, T.longibrachiatum,T.hamatum and T.viride.When Pythium sp.was treated with antago- nistic Trichoderma,its hapha would be broken into small segments,which was different from the resuet in antagonism of Trichoderma againt Rhizoctonia solani.The wheat bran culture or an antagonistic isolate of T.harzianum was used in controling damping-off of tomato seedling in hotbed.The result,which was similar to that produced by fungicide PCNB and slightly better than Dixon,was quite satisfied with a decrease of disease inci- dence by 29.4 percent as compared with control.The hothed that was made from ferment material might be of particular advantage to both growth of Trichoderma and its nutrition competition.Therefore,there was great possibility in controling with Trichoderma against damping-off of vegetable seedling sown in early Spring.