增效浏阳霉素防治叶螨的效果和对智利植绥螨影响的研究

在实验室内用5％增效浏阳霉素乳油1000倍液防治截形叶螨,24小时后的死亡率为95.5％。对三氯杀螨醇有较强抗性的二斑叶螨和朱砂叶螨,48小时后的死亡率也达90％左右。浏阳霉素对3种叶螨均无杀卵作用,但施药5～6天后,对初孵幼螨仍能杀死90％以上。低温能降低浏阳霉素的药效。在温室中施药一周后。对二斑叶螨的雌成螨无残效,但幼螨和前若螨的死亡率可达97.4％。以磷酸兰苯酯作增效剂的浏阳霉素比亚磷酸三苯酯作增效剂的药效好。在同一剂量下,对二斑叶螨的死亡率分别为98.2％和53.4％。5％浏阳霉素的1000倍液对智利植绥螨成螨的生存率、在叶上的定居率及着卵量均无影响。在温室栽培月季上喷药1次防治二斑叶螨,36天后防治效果仍保持在99％,而用三氯杀螨醇和敌敌畏防治,施药一周后需再次防治。

CONTROL EFFECT OF THE ENHANCED LIUYANGMYCIN ON LEAF SPIDER MITES AND ITS INFLUENCE ON THE BENEFICIAL PHYTOSEIID PREDATORS

Liuyangmycln, a new antibiotic against spider mites, is a tetranactin isolated from Streptomyces griseolus in Hunan, China. In the laboratory tests, application of 5% Enhanced Liuyangmycin emusion (1:1,000. solution) resulted in a 95.5% mortality of Tetranychus truncatus Acari: Tetranychidae] in 24 hours. The 43 hours mortality of T. urticae and T. cinnabarinus, which were resistant to such chemical miticide as dicofol, was about 90%. The antibiotic showed no effect on the eggs of the leaf mites. But the mortality of newly hatched mites was above 90% 5-6 days after the-application. In the greenhouse tests, no residual effect was found on the female adults of T. urticae, but the mortality of the early instar larvae and protonymphs was 97.4% one week after the application. Low temperature influenced the control effect.Triphenyl phosphate was found to be a better synergist of Liuyangmycih than triphenyl phosphite. The mortalities of T. urticae by using Liuyangmycin with the two synergists at the same dosage were 98.2% and 53.4%, respectively. It was found that the settlement, survival rate and oviposition of Phytoseiulus persimilis Acari: Phytosdiidae] were not influenced by the antibiotic. A 99% control effect of T. urticae on Rosa chinensis was obtained 36 days after an application in the greenhouse, while the control effect of dicofol and DDVP lasted for only one week.