麦—棉邻作天敌转移规律研究

对麦收期小麦不同高度的天敌分布调查以及麦—棉邻作棉田和棉—棉邻作棉田天敌数量在麦收前后的变化调查 ,结果表明 :蜘蛛类、食虫蝽类、隐翅甲类天敌主要栖息在距地面 10cm以下麦杆及地表杂草上 ,而草蛉类、瓢虫类则主要栖息在距地面 10cm以上的麦杆上 ,而且麦田天敌在麦杆 10cm以下栖息数量远大于距地面 10cm以上的数量 ;麦收后 ,麦田的天敌迅速转移至与之相邻的棉田 ,其中 ,瓢虫类和草蛉类等飞行能力较强的天敌首先扩散 ,比蜘蛛等爬行类类天敌先进入棉田 ;麦—棉邻作棉田麦收后的天敌数量是麦收前的 2 5 .7倍 ,而且明显高于棉—棉邻作的棉田天敌数量 ;距离麦田 2 5 ,50 ,75m的棉田天敌数量在麦收前并无明显的差异 ;麦收后则明显呈现出棉田天敌数量距麦田 2 5m >距麦田 50m >距麦田 75m这一规律。

Study on the Dispersion of Natural Enemy between Wheat Field and Cotton Field

The investigation of natural enemy's distribution in different height of wheat shows that those creeping natural enemiese mainly locate on the ground or on the wheat straw under ten centimetre and those flying natural enemiese mainly locate on wheat straw above ten centimetre. After wheat harvest, ladybugs disperse in cotton field first.The quantity of them are much more than that of others. There is no difference on quantity of natural enemy in cotton field between near wheat field and near cotton field before wheat harvest. But the quantity of natural enemy in cotton field near wheat field are many times as much as those near cotton field. The cotton field are farther from wheat field, the natural enemiese are fewer after harvest.