浅黄恩蚜小蜂和丽蚜小蜂对温室白粉虱的寄生潜能分析
Analyses of parasitism potential of parasitoid wasps Encarsia sophia and Encarisa formosa on the greenhouse whitefly Trialeurodes vaporariorum

浅黄恩蚜小蜂Encarsia sophia Girault & Dodd和丽蚜小蜂Encarsia formosa Gahan是防治粉虱类害虫的优势寄生蜂,通过生命表技术方法分析了2种寄生蜂对温室白粉虱Trialeurodes vaporariorum (Westwood)的防治潜能.结果表明,丽蚜小蜂在羽化第3天和第10天出现2次寄生高峰,占其总寄生量的13.7%和8.0%,在2次高峰之间逐日寄生粉虱数量比较平稳,单雌逐日平均产雌数保持在10.6~13.4头,10 d后寄生量呈明显的下降趋势;而浅黄恩蚜小蜂羽化10 d内逐日寄生粉虱量变化不大,单雌逐日产雌数稳定在4.2~5.4头,羽化14 d后寄生量呈明显下降趋势.丽蚜小蜂和浅黄恩蚜小蜂的R0、T、rm、λ值分别为171.5、18.0、0.2854、1.3303和61.6、16.2、0.2544、1.2897;粉虱若虫充足时,丽蚜小蜂平均单雌寄生若虫数是浅黄恩蚜小蜂的2.7倍,而后者平均单雌取食若虫数为60.6头,明显高于前者42.7头,总的来看,丽蚜小蜂通过寄生和取食杀死粉虱总量220.8头,明显高于浅黄恩蚜小蜂的127.9头.表明在应用寄生蜂防治温室白粉虱时,单独释放丽蚜小蜂比浅黄恩蚜小蜂显示出更好的防治潜能.
Encarsia sophia Girault & Dodd and Encarsia formosa Gahan are considered as dominant parasitoids against whiteflies currently. In this study, their biological control potentials on the greenhouse whitefly, Trialeurodes vaporariorum (Westwood) were compared and analyzed with the parameters of life tables. The results showed that E. formosa had two parasitism peaks at the 3rd and 10th day after emergence, with 13.7% and 8.0% nymphs parasitized in total number, respectively. There were a steady number of nymphs parasitized daily between the two parasitism peaks, in which the daily number of female progeny produced by a surviving female kept at 10.6-13.4. However, the number of whitefly nymphs parasitized by E. formosa decreased significantly from 10th day after emergence. There were a steady number of nymphs parasitized daily by E. sophia in 10 days after emergence, in which the daily number of female progeny laid by a surviving female kept at 4.2-5.4. The number of whitefly nymphs parasitized by E. sophia decreased significantly from 14th day after emergence. The R0, T, rm, λ of E. formosa and E. sophia on T. vaporariorum nymphs were 171.5, 18.0, 0.2854, 1.3303, and 61.6, 16.2, 0.2544, 1.2897, respectively. When an adequate supply of whitefly nymphs was offered, the number of hosts parasitized by E. formosa was 2.7 times that of E. sophia. However, E. sophia averagely fed on 60.6 whitefly nymphs, significantly higher than E. formosa (42.7 nymphs). Generally, the number of whitefly nymphs killed through host feeding and parasitism by E. formosa (220.8 nymphs) was significantly higher than that by E. sophia (127.9 nymphs). These results indicated that releasing E. formosa had better biological control potential than E. sophia for the management of T. vaporariorum.