南昌小菜蛾种群动态、天敌种类调查及4种药剂的应用

Population Dynamics, Natural Enemy Species and the Application of Four Pesticides on Diamondback Moth in Nanchang

协调寄主、天敌与农药之间的关系是合理使用高效低毒药剂控制害虫的基础。为此,调查了江西南昌地区小菜蛾的种群动态和天敌种类,并评价了4种药剂对小菜蛾的防治效果及其对捕食性天敌种群的影响。结果表明:南昌地区小菜蛾成虫和幼虫每年均有2个发生高峰,即春峰和秋峰,春峰主要发生在4~6月,秋峰发生在10~11月;该地区小菜蛾天敌有16种,其中菜蛾绒茧蜂、菜蛾啮小蜂、草间小黑蛛、八斑球腹蛛和异色瓢虫是优势天敌,其种群数量与小菜蛾的种群数量呈现出天敌追随现象;综合分析4种杀虫剂的影响,认为在生产上宜优先选择施用6%乙基多杀菌素SC和24%甲氧虫酰肼SC,20亿PIB/mL甘蓝夜蛾核型多角体病毒SC不宜单独用于小菜蛾的防治,需与乙基多杀菌素等速效性好的药剂配合使用或在小菜蛾种群数量较低的情况下使用,而10.5%三氟甲吡醚EC则应在小菜蛾重发生、而天敌又很少时应用。

Coordinating the relationship between the host,the natural enemy and the pesticide is the basis for the rational use of high efficiency and low toxic agents to control the pests.For this,we investigated the population dynamics and natural enemy species of diamondback moth in Nanchang area of Jiangxi Province,and evaluated the effects of 4 insecticides on both of them.The results showed that there were 2 peaks in the emergency of adult and larva of diamondback moth every year,named spring peak(mainly in April to June)and autumn peak(October to November).There are 16 natural enemies of diamondback moth in the area,among which Cotesia plutellae Kurdjumov,Oomyzus sokolowskii Kurdjumov,Erigonidium graminicolum Sundevall,Coleosoma octomaculatum Boes.et.Str.and Leis axyridis Pallas are the dominant natural enemies,the number of population and the amount of diamondback moth showed a natural enemy following phenomenon.After comprehensive analysis of the effects of these 4 insecticides,we could conclude that 6%spinetoram SC and 24%methoxyfenozide SC should be given priority to the application in practice.Besides,mamestra brassicae nuclear polyhedrosis virus(MBNPV)SC(2 billion PIB/mL)should not be used alone,which should be used in combination with a quick-effective pesticides like spinetoram,or MBNPV can be used when the population of diamondback moth is relatively low.Moreover,10.5%pyridalyl EC could be used in the regions where there is a large occurrence of diamondback moth and the natural enemies are few.