橡胶盔蚧高效低毒防治剂的筛选

Screening of Highly Effective and Low Poisonous Insecticides against Parasaissetia nigra (Nietner)

室内玻片浸渍法测定了9种毒性较低的农药对橡胶盔蚧Parasaissetia nigra(Nietner)1龄若虫(初孵)的毒力。结果表明:1.2%苦参碱·烟碱乳油的毒力最高,LC50值为0.65mg/L,3%苯氧威乳油的毒力次之,LC50值为0.75mg/L,2.5%高效氯氰菊酯乳油的LC50值为8.19mg/L,三者均高于对照40%机油·杀扑磷乳油和40%杀扑磷乳油的毒力;20%敌百虫·乙酰甲胺磷乳油、40%乐果乳油、25%喹硫磷乳油和48%毒死蜱乳油的毒力也较高,LC50值均小于100mg/L;30%乙酰甲胺磷乳油和80%敌敌畏乳油的毒力最差,LC50值分别为124.67、288.93mg/L。3种毒力高的药剂(对水)对2年生橡胶苗上的试验结果表明:2.5%高效氯氰菊酯乳油对已固着在枝条上的橡胶盔蚧1龄若虫有较好的防治效果,与对照药剂40%机油·杀扑磷乳油的防效相当,优于1.2%苦参碱·烟碱乳油和3%苯氧威乳油。3种杀蚧剂配制的热雾剂对橡胶盔蚧1、2龄若虫防治试验结果表明:苦参碱·烟碱和苯氧威的防效较好,药后16d防效均在80%以上,与对照杀扑磷的防效相当。

The toxicities of 9 insecticides to the newly hatched nymph of Parasaissetia nigra （Nietner） were tested respectively by slide-dip method in laboratory. The results show that matrine, nicotine 1.2% EC has the highest toxicity with LCs0 value 0.65 mg/L and fenoxycarb 3% EC was a little less toxic with LC50 value 0.75 mg/L, beta-cypermethrin 2.5% EC with LC50 value 8.19 mg/L. Each of them is more toxic than lubricating oil. methidathion 40% EC and methidathion 40% EC as control. The toxicities of trichlorfon.acephate 20% EC, dimethoate 40% EC, quinalphos 25% EC and chlorpyrifos 48% EC are moderate with LC50 value less than 100 mg/L. The acephate 30% EC and dichlorvos 80% EC are low toxic with LC50 value 124.67 and 288.93 mg/L respectively. Field plot experiments of the upper 3 insecticides with high toxicity against first-instar nymph of P. nigra on 2-year-nursery-rubber trees indicate that beta-cypermethrin has better control effect than matrine.nicotine and fenoxycarb, which was almost as the same effective as lubricating oil-methidathion 40% EC. Hot fogging concentrations confected by the 3 insecticides were tested to control the first-instar and second-instar nymph of P. nigra on tapping rubber trees. The result was that the control effect of matrine-nicotine and fenoxycarb was upper 80% as good as that of lubricating oil. methidathion at 16 days insecticides sprayed, better than that of beta-cypermethrin.