二化螟越冬幼虫在稻株内的分布及其控制技术研究

研究了二化螟越冬代幼虫在不同虫口密度田块和不同受害程度稻株内的分布情况以及农事操作技术措施对越冬二化螟的防治效果。结果表明:二化螟幼虫在水稻植株上的分布数量表现为随着稻株离地面高度的升高而减少,且这种分布趋势与田间的二化螟幼虫密度无关;二化螟幼虫在不同受害程度的稻株上的分布均以5~10 cm的稻株部位最多。在翌年春季,在稻草上越冬的二化螟出蛾率(36.44%)高于在稻桩上越冬的二化螟出蛾率(27.11%),但是在稻桩上越冬二化螟的出蛾数量(138.25)极显著高于在稻草上越冬二化螟的出蛾数量(34.25)。"火烧+堆沤"(冬前在田间对稻草进行焚烧,翌年早春再进行堆沤)处理和旋耕处理对越冬二化螟的防治效果均较好,防效分别为71.17%和66.25%,显著高于单独焚烧稻草或单独堆沤处理的防治效果。

Studies on Distribution of Overwintering Larvae of Chilo suppressalis (Walker)in Rice Stem and Its Control Technique

In order to make clear the distribution of overwintering larvae of Chilo suppressalis(Walker) in rice stem and obtain the effective control technique against C.suppressalis during overwintering,the control efficiency of different agricultural measures on the overwintering larvae of C.suppressalis and its distribution in rice stem damaged by different densities of larvae and with different injured degrees were studied,respectively.The results indicated that the overwintering larvae of C.suppressalis in rice stem decreased along with the increasing of rice stem height from the ground,and this distribution pattern was irrelevant to the larvae density in paddy field.The larvae in the rice stems damaged at different degrees mainly concentrated within the rice stem with the height of 5~10 cm from the rice roots.In the next early spring,the eclosion rate of C.suppressalis overwintered in rice straw(36.44%) was higher than that in rice stubble(27.11%),but the eclosion number of C.suppressalis overwintered in rice stubble(138.25) was significantly higher than that in rice straw(34.25).Some agricultural measures,such as "tillage with rotary tiller" and "burning rice straw before overwintering and then retting rice stubble before the eclosion of C.suppressalis in the next early spring",had obvious control effect against C.suppressalis,their control effects were 66.25% and 71.17%,respectively,which were significantly higher than the control effect of alone burning rice straw before overwintering and that of alone retting rice stubble before the eclosion of C.suppressalis in the next early spring.