泽兰实蝇对紫茎泽兰寄生及株高与繁殖性能的影响

为了解野外自然条件下泽兰实蝇(Procecidochares utilis Stone)对紫茎泽兰(Eupatorium adenophorum Spreng)的寄生特征,采用随机抽样调查和样方调查法,探讨了林下与空旷地的居民区、柏树林、松树林、桉树林和杂草地等5种不同生镜下的泽兰实蝇自然寄生率。结果表明:林下和空旷地的泽兰实蝇寄生率无显著差异。5种不同生镜下的泽兰实蝇寄生率存在显著差异,以桉树林最高,为60.5%,居民区次之,为46.2%,杂草地为32.5%,柏树林最低,为25.1%。泽兰实蝇寄生产生的虫瘿大多分布在紫茎泽兰植株较幼嫩部分,以距顶1~34cm虫瘿数最多,占调查总虫瘿数的72.2%。5种生镜下紫茎泽兰植株上的虫瘿个数均以结1~2个虫瘿为主,结3个及3个以上虫瘿的较少。从平均每瘿虫口数看,虫瘿大的平均每瘿虫口数多,虫瘿小的平均每瘿虫口数少。此外,泽兰实蝇寄生对紫茎泽兰的株高和有性繁殖力均无显著影响,说明泽兰实蝇寄生对紫茎泽兰的控制作用不明显。

Effects of Procecidochares utilis on Parasitism,Height and Reproductive Performance of Eupatorium adenophorum

The natural parasitism rate of P.utilis under five habitats of residential area, Cypress forest, Pinus forest, Eucalyptus forest and weed area is analyzed by the random sampling and sample plot investigation methods to discuss the parasitism characteristics of P.utilis on E.adenophorum under field natural condition.Results: There is no significant difference in parasitism rate of P.utilis between field and under-forest but there are significant differences in parasitism rate of P.utilis among five habitats.The P.utilis parasitism rate of five habitats is Eucalyptus forest (60.5%) > residential area (46.2%) > weed area (32.5%) > Pinus forest (27.0%) >Cypress forest (25.1%).Most insect galls produced by P.utilis distribute on young part of E.adenophorum plants and 72.2% of total investigated insect galls distributes the top of E.adenophorum plants (1~34 cm).The insect gall number per E.adenophorum plant is 1~2 under five habitats mostly.3 and more than 3 insect galls per E.adenophorum plant is less under five habitats.The bigger the insect gall is, the more the average population is.The parasitism of P.utilis has no significant effects on height and sexual fecundity of E.adenophorum, which indicates that parasitism of P.utilis has no obvious control effect on E.adenophorum.