Current status of the greenhouse whitefly, Trialeurodes vaporariorum, susceptibility to neonicotinoid and conventional insecticides on strawberries in southern California

Since 1998, the greenhouse whitefly, Trialeurodes vaporariorum Westwood (Homoptera: Aleyrodidae), has emerged as a major insect pest of many horticultural crops in coastal California. Control of this pest has been heavily dependent upon chemical insecticides. Objectives of this study were to determine the status of the greenhouse whitefly susceptibility to neonicotinoid and conventional insecticides on strawberries in Oxnard/Ventura, a year-round intensive horticultural production area of southern California. For bioassay tests, adult whiteflies were collected from commercial strawberry crops, and immatures were directly developed from eggs laid by these adults. LD(50) values of soil-applied imidacloprid, thiamethoxam and dinotefuran were respectively 8.7, 3.2 and 4.9 times higher for the adults, 1.8, 1.2 and 1.5 times higher for the first-instar nymphs and 89.4, 390 and 10.4 times higher for the third-instar nymphs than their top label rates. LC(50) values of foliar-applied imidacloprid, thiamethoxam and acetamiprid were respectively 6.1, 6.0 and 1.7 times higher for the adults and 3.8, 8.7 and 4.4 times higher for the second-instar nymphs than their top label rates. For the adults, LC(90) values of endosulfan, malathion, methomyl, bifenthrin and fenpropathrin were 2.2, 1.2, 1.9, 2.3 and 4.9 times lower than their respective top label rates. Chlorpyrifos was not very effective against the adults, as indicated by its LC(90) being 120% higher than its top label rate. The present results strongly emphasize the need to develop resistance management strategies in the region.     

阿克泰防治温室白粉虱的研究

本文就阿克泰防治温室白粉虱的技术要点进行了研究，阿克泰25%水分散粒剂2g/mu防治温室白粉虱具有很好的防效，防效可达95%，持效期长达15d以上。     

在黏虫板控制状态下温室白粉虱空间分布调查初报

在利用黏虫板控制虫情的条件下,通过系统调查,初步明确了在冬、春季温室白粉虱具有向温室后部集中和趋向植株上部的特性,为该虫科学监测和防治提供了依据。     

辣椒碱与3种药剂对温室白粉虱的联合毒力

为了筛选出对温室白粉虱 Trialeurodes vaporariorum 具有增效作用的农药复配组合, 室内采用玻璃管饲喂法测定了辣椒碱与吡虫啉?溴氰虫酰胺?苦参碱复配对温室白粉虱初羽化成虫的联合毒力, 并以共毒因子法与共毒系数法对各复配组合的联合毒力进行评价?试验结果表明, 共毒因子大于20的配比共6组, 进一步细化配比后筛选出共毒系数大于120的复配组合, 其中14组具有增效作用, 辣椒碱分别与吡虫啉?溴氰虫酰胺?苦参碱按287∶1?1 558∶1?423∶1复配时增效作用最显著, 其共毒系数分别为257.89?255.65?248.80, LC50分别为31.83?128.07?98.87 mg/L?辣椒碱与吡虫啉按287∶1复配为最佳复配组合?     

海氏桨角蚜小蜂对不同龄期Q隐种烟粉虱和温室白粉虱的取食和寄生选择

许多粉虱寄生蜂雌蜂对粉虱若虫的攻击方式不仅是寄生,而且还能取食。本文以海氏桨角蚜小蜂Eretmocerus hayati作为测试寄生蜂,Q隐种烟粉虱和温室白粉虱作为寄主,在非选择和双向选择条件下调查了寄生蜂对寄主的取食和寄生选择性。研究结果表明,非选择试验条件下,海氏桨角蚜小蜂48 h内取食1～4龄烟粉虱和温室白粉虱若虫的数量分别为10.7、6.4、6.7、5.0头和4.4、3.7、2.8、2.3头,寄生1～4龄烟粉虱若虫的数量分别为22.1、27.5、25.4、16.5头,但不能寄生各龄期温室白粉虱若虫;而在选择试验条件下,寄生蜂取食1～4龄烟粉虱若虫的数量分别为同龄期温室白粉虱若虫数量的1.8、2.6、2.5、1.5倍。说明寄生蜂的取食寄主能力明显受寄主种类和龄期的影响。海氏桨角蚜小蜂更适合用来防治烟粉虱,但不适于防治温室白粉虱。     

设施蔬菜粉虱的危害及综合防治策略

概述了严重影响天津地区设施蔬菜生产的温室白粉虱和B-型烟粉虱的发生特点及危害特征,并提出其防治策略。     

Comparative whitefly transmission of Tomato chlorosis virus and Tomato infectious chlorosis virus from single or mixed infections

Tomato chlorosis virus (ToCV) and Tomato infectious chlorosis virus (TICV) are two criniviruses that are emerging worldwide, and induce similar yellowing diseases in tomato crops. While TICV is transmitted only by Trialeurodes vaporariorum , ToCV is transmitted by three whitefly species in two genera Trialeurodes vaporariorum , T. abutilonea and Bemisia tabaci . The efficiency of transmission by T. vaporariorum from plants infected by one virus or by both was compared, and the probability of virus transmission by a single whitefly was derived from group testing experiments. The estimated transmission probabilities ranged from 0·01 to 0·13, and were not significantly different between ToCV and TICV, or between single and mixed infections. Experiments using B. tabaci as a vector and source plants infected by TICV and ToCV did not reveal any functional trans-complementation for transmission of TICV by ToCV, suggesting that if this phenomenon occurs in nature, it is at a very low frequency. Possible reasons why TICV did not establish in southern France while ToCV is now endemic are discussed.     

丽蚜小蜂对雪莲果和烟草繁育温室白粉虱的适应性

雪莲果和烟草均属于大叶型植物,是繁育温室白粉虱Trialeurodes vaporariorum Westwood的理想寄主植物。为了明确雪莲果作为中间寄主植物大量繁育丽蚜小蜂Encarsia formosa Gahan的可行性,在人工气候室条件下,比较研究了丽蚜小蜂在雪莲果和烟草繁育温室白粉虱上的寄生率、羽化率和发育历期。研究结果表明,丽蚜小蜂对雪莲果和烟草繁育的温室白粉虱3龄若虫寄生率最高,分别为84.2%和80.3%,且对雪莲果繁育的温室白粉虱1和2龄若虫寄生率均显著高于烟草;丽蚜小蜂寄生两种寄主植物繁育的温室白粉虱羽化率除1龄外差异均不显著,其中寄生雪莲果和烟草繁育3龄粉虱若虫的羽化率最高,分别为94.7%和93.8%;丽蚜小蜂寄生雪莲果繁育1～4龄若虫发育历期分别为21.4、15.5、13.7和13.3 d,且寄生雪莲果各龄粉虱若虫发育历期除1龄外均短于烟草。综合来看,与烟草相比,丽蚜小蜂对雪莲果繁育的温室白粉虱表现出更好的适应性,特别是对3龄若虫表现出最好的发育适合度,这为进一步开发利用雪莲果为中间寄主植物大量繁育丽蚜小蜂提供了理论依据。     

丽蚜小蜂释放密度和释放时间对温室白粉虱防治效果的影响

研究了丽蚜小蜂不同释放密度和不同释放时间对温室白粉虱防治效果的影响。结果表明：当白粉虱平均虫口密度为0.5头／株时,丽蚜小蜂释放密度保持在150000头／hm^2。、分3～4次释放对温室白粉虱防治效果最佳,防效可高达95.4％。     

Detection of a related difference in efficacy of azadirachtin treatments for the control of whiteflies on Gerbera jamesonii by testing for interactions in generalised linear models

BACKGROUND: Within a project cluster, systemical effects of two neem treatments (Neem Azal? U and Neem Pellet) on the number of Trialeurodes vaporariorum (Westw.) in Gerbera jamesonii Flori Line Maxi were investigated. In order to minimise adverse ecological effects of a product, a new plant protection product can be declared as superior to a reference if it shows the same or a higher effect at a lower dosage. RESULTS: Based on a negative binomial model, the efficacy of the two treatments is compared by applying a user‐defined interaction contrast in a multiple‐contrast test framework. The corresponding calculation of simultaneous confidence intervals for the ratio of model parameters provides conclusions about statistical significance and biological relevance. The validity of the approach is shown by a small simulation study. As a result of the experiment, besides a significant difference between two negative control treatments, no significant difference between the efficiency of the two neem treatments (Neem Azal? U and Neem Pellet) could be detected. CONCLUSIONS: Simultaneous confidence intervals for linear combinations of parameters of generalised linear models provide a useful way to compare the efficiency of two plant protection products. The results for the azadirachtin experiment indicate that large differences between any application effects of either Neem Azal? U or Neem Pellet cannot be expected. Copyright © 2009 Society of Chemical Industry