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采用田间笼罩接虫观察和自然虫口密度为害调查,结果表明,甜菜夜蛾对大葱的为害表现为大葱生长前期损失重,后期损失轻;同一生育期内虫口密度与产量损失呈显著的正相关。大葱移栽期、葱白伸长期、成熟期与之对应世代的1个幼虫历期内,每100株大葱1头幼虫的产量损失分别为2.03%、0.48%、0.20%;其对应的为害株率防治指标分别为2.82%、22.84%、40.92%。
The results showed that the damage caused by Spodoptera exigua showed that the weight loss of early stage of the green onions and the loss of the later period were light. The density of the population was positively correlated with the loss of yield during the same growth period. In the transplanting period of green onions, the elongation of green onions and the larvae corresponding to one generation in mature period were 2.03%, 0.48% and 0.20% respectively for the yield of one green onions per larva. The corresponding damage rate Control indicators were 2.82%, 22.84%, 40.92%.