油菜开花进程与菌核病防治适期的关系

Studies on the Relationship between Rape Flowering and Control Time of Rape Sclerotiorum.

４月上、中旬油菜开花率达１０％～３０％，即一次分枝开花株率５０％～１００％时，花瓣保湿培养带菌率最高，是菌核病病菌侵染花瓣的主要时期，也是药剂防治的关键时期。试验表明：油菜菌核病防治最佳适期为主茎开花株率８０％～１００％至一次分枝开花株率９５％～１００％，用克菌灵２２５０ｇ／ｈｍ２防治一次，防病效果达７０％以上，保产效果达５０％左右，第一次适期用药后，隔５～７ｄ再用药一次，能将菌核病的危害损失控制在最低限度。

The relationship between rape flowering and control time of rape sclerotiorum (Sclerotinia sclerotiorum) was studied.When perentage of rape plant flowered came up to 10%～30%,i.e,.the percentage of plants 1 st branch flowered was 50%～100%,the percentage of rape petals with fungus,which were confirmed under high humidity,was the highest during the 1 st to 2 nd ten day period of April.Therefore this period was the key stage of infection and chemical control for rape sclerotiorum.The best spraying time to control rape sclerotiorum falled the period from rape stems of 80%～100% with flowers to the 1 st branch of 95%～100% with flowers.the effect of kejumlin (carbendazim+borid fertilizer)at 2.25kg/hm 2 were 70% on disease control and yield protecting and 50%,respectively.Another spray of Kejumlin should be used after 5～7 days'interval,otherwise the incidence and damage of rape sclerotiorum could not be effectively controlled.