水稻大螟为害规律的调查与研究

通过对大螟田间分布规律的调查分析,明确了大螟的趋边集中为害行为.幼虫侵入水稻方式以从剑叶叶鞘缝侵入和从剑叶叶鞘处咬孔侵入为主.幼虫为害水稻造成白穗,随为害茎节的升高而加重,以穗茎节为主,占80%左右,其次是穗茎下第一节.一至四龄幼虫为害均能造成水稻白穗,以二龄为害造成白穗为主,平均为86.7%.据此提出了大螟的测报调查方法,防治时期应在水稻破口期和卵孵高峰期,以及轻发年份田边挑治、重发年份全田用药的防治策略.

Research on the Infestation of Sesamia inferens

The infestation behaviors of Sesamia inferens was noticed by assembling at the edge of rice field,the result was confirmed based on the investigation and analysis of distributing regulation.The main invasion method of grub is invading directly form lea f gap of the leaf sheath and bore a hole in leaf sheath.The higher the harmed stem,the more severe damage to white spikes.White spikes that caused by g rubs were up to 80%and the first cane bellow the ear stem was the next.Lava from the first to the fourth stag e can cause white spikes.The grubs mainly caused White spikes in the sec ond stage and the rate of white spike was up to 86.7%of the total white spikes.Based on the result of investigation,the investigation of forecast was put forth.The strategy of con trolling the harm of Sesamia inferens was in the stage of rice early earring and depositing peak of Sesamia inferens,se-lective controlling the insect on th e edge of rice field in case of lightly infestation years,and spraying the whole field in case of severely infestatio n years.