几种药剂对苹果园山楂叶螨及其天敌中华草蛉和有益鈍绥螨的影响

1983—1984年在室内测定了10种化学药剂对苹果园山楂叶螨及其天敌中华草蛉、有益钝绥螨的相对毒力、选择毒效,用4种药剂在北京西郊的苹果园做了防治试验。结果表明克螨特、三环锡、三唑锡、三氯杀螨醇为对天敌安全的高效选择性杀螨剂。螨完锡对天敌安全,对山楂叶螨卵—若螨期高效,但对雌成螨速效较差。双甲脒对山楂叶螨高效,对中华草岭安全,但对有益钝绥螨的影响很大。乐果、氧化乐果、二溴磷、二嗪农等4种有机磷药剂均对山楂叶螨无效或毒力很低,对天敌影响很大。田间调查表明,在常年正常使用化学药剂的苹果园,叶螨的天敌很少。在常年不使用化学药剂的苹果树上,天敌较多,对山楂叶螨的控制作用十分显著,天敌优势种为有益钝绥螨,两年调查的累积数量分别占天敌累积数量的81.3%和89.9%,其次为塔6点蓟马,占16.9%和9.3%。

EFFECTS OF SEVERAL PESTICIDES ON THE HAWTHORN SPIDER MITE AND ITS NATURAL ENEMIES, THE CHINESE LACEWING AND A PHYTOSEIID MITE

Laboratory and field studies on the effects of several pesticides on some natural enemies were carried out in Beijing in 1983-84. The results showed that amitraz, cyhexatin, propargite, azocyclotin, fenbutatin oxide and dicofol were highly toxic to the hawthorn spider mite, Tetranyehus viennensis Zacher, and relatively innocuous to a predatory phytoseiid mite,Amblyseius wfilis Siang et ke and the Chinese lacewing, Chrysopa sinica Tjeder,except that fenbutatin oxide was low toxic to the female adults of the hawthorn spider mite and amitraz was very harmful to the predaceous mite. Four organophosphorus pesticides, dimethoate, omethoate diazinon, and haled were destructive to the predators and had very low acaricidal activity against the hawthorn spider mite due to resistance. The traditional use of wide-spectral insecticides brought about an almost complete elimination of the predators in a commercial apple orchard, but high predator population, on the contrary, were maintained throughout the growth season and resulted in good control of phytophagous mite in the apple trees, to which never no pesticides have sprayed. The most predominant predator was the phytoseiid mite,A.wfilis, which made up 81.3 aud 89.9% of the total predators collected in 1983-84, respectively.