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一、地老虎1.危害性。地老虎是一种分布广泛危害严重的地下害虫。其幼虫危害幼苗,幼虫咬食小苗时,在地面咬断嫩茎,造成缺苗断垄,伸蔓以后咬断瓜蔓顶端生长点及叶柄,影响生长发育。老龄幼虫则分散危害,白天藏起来晚上出来活动,咬断西瓜根茎,以第一代幼虫危害最重。地老虎一年繁殖三代,以老熟幼虫和蛹在土壤中越冬。越冬的幼虫羽化和产卵期在3月上旬、4月中旬至5月中旬为第一代幼虫危害盛期。春季幼虫在4月上旬至5月上旬,在阴雨或土壤湿润的情况下危害瓜苗较为严重,刚孵化的幼虫,昼夜在寄主心叶中取食。3龄以后转入土中,4龄以后常把幼苗齐地面咬断,5~6龄为暴食期,食量大,要及时防治。2.防治办法:(1)精耕。冬前深翻土地,破坏天敌越冬环境,可使幼虫冻死。早春及时清理田园,
First, the tiger 1. Hazard. The tiger is a widely distributed underground pest. The larvae endanger seedlings, larvae bite seedlings, bite off tender stems on the ground, resulting in lack of seedlings off the ridge, stretching vine after bite cut the top of the melon growth points and petiole, affecting growth and development. Aged larvae are dispersed hazards, hide out during the day out activities, sever watermelon rhizome, the first generation of larvae hardest hit. To year-old tiger breeding three generations, with mature larvae and pupa in the soil overwintering. Overwintering larval emergence and spawning period in early March, mid-April to mid-May for the first generation larvae peak. Spring larvae in early April to early May, in the rainy or humid soil damage more serious melon, just hatching larvae, day and night feeding in the host heart leaf. After 3 years into the soil, 4 years after the seedlings often snapped on the ground, 5 to 6 years of gluttony period, food intake, should be timely prevention and treatment. 2. Prevention and control methods: (1) intensive farming. Deep winter before turning the ground, destruction of natural enemies overwintering environment, allows the larvae to freeze to death. Early spring clean up the pastoral,