粟灰螟是为害谷子的主要害虫。谷子在苗期受害后造成枯心苗,枯心苗率常达10～20％,严重年份达50％以上,产量损失可达15～20％左右。 发生原因 粟灰螟的发生与为害程度,主要决定于虫源基数、气象条件和谷子生育期等三大因素的综合作用。 一、虫源基数。据研究报道,越冬幼虫平均每亩有活虫100头时,谷子枯心苗率为10％左右;亩有活虫140头时,谷子枯心苗率为25％左右;平均百茬活虫达3头以上时,谷子枯心苗率可达10～20％。 1.粟灰螟是钻蛀性害虫,由于不掌握其发生规律,抓不准防治适期,当发现田间出现枯心苗,幼虫已蛀入茎内,防治很困难,因此虫口基数连年积累,越冬基数就大。 2.各级农技部门对粟灰螟发生为害 Milletia borer is the main pest damage millet. Millet caused seedlings after seedling damage, dead-hearted seedlings often up to 10 to 20%, severe years up to 50%, the yield loss of up to 15 to 20%. Occurrence of the occurrence of corn borer and harm degree, mainly determined by the insect base, meteorological conditions and the growth of millet three major factors such as the combined effect. First, the source of insects. According to the research report, the average number of overwintering larvae per 100 live mu insects, millet seedlings rate of about 10%; acres of living insects 140, millet seedling rate of about 25% 3 or more, millet seedling rate of up to 10 to 20%. 1. Aspergillus borer is a boring insects, because they do not grasp the occurrence of law, not allowed to prevent arrest period, when the field found dead seedlings, larvae have been moulted into the stem, prevention and control is very difficult, so insects base accumulation year after year, Overwintering base is large. 2. Agricultural departments at all levels on the occurrence of corn borer damage