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自1980年以来,马铃薯瓢虫一直是我县三川、冷水、叫河、陶湾四乡的马铃薯主要害虫。尽管年年防治,虫口密度有增无减,一般减产50％以上,发生面积2.1万亩。 1985年开始推广春玉米地膜覆盖新技术,玉米由单行变双行密度增加,马铃薯面积相对减少,7月下旬马铃薯收获后,马铃薯瓢虫成虫大量迁移到玉米雌穗上嚼食花丝,危害后雌穗形成乱麻状或平顶。据1989年8月7日至9日在该地区调查,穗被害85％,百穗有虫128头,单穗最高有虫12头。个别玉米叶片也受害。 马铃薯瓢虫危害玉米的特点:地膜覆盖春玉米(该地区海拔高度1200-1300米,系高
Since 1980, potato ladybugs have been the main pests of potato in Sanchuan, Lengshui, Jiahe and Taowan Townships in our county. Despite the annual control, pest population density unabated, the general reduction of more than 50%, the occurrence of an area of 21000 acres. In 1985, the new technology of spring maize mulching was popularized. The density of maize increased from single row to double row, and the area of potato decreased. After the potato was harvested in late July, the adult potato ladybugs migrated to the corn ears of maize, Spikes form a hemp or flat top. According to the survey conducted in the area from August 7 to August 1989, 85% of spikes were emasculated, 128 were found per earnails and 12 were highest on single spikes. Individual corn leaves also suffer. Potato ladybugs harm the characteristics of corn: plastic mulching spring corn (the region at an altitude of 1200-1300 meters, the Department of high