Natural Control of Cereal Aphids (Homoptera: Aphididae) by Entomopathogenic Fungi (Zygomycetes: Entomophthorales) and Parasitoids (Hymenoptera: Braconidae and Encyrtidae) on Irrigated Spring Wheat in Southwestern Idaho
Natural Control of Cereal Aphids (Homoptera: Aphididae) by Entomopathogenic Fungi (Zygomycetes: Entomophthorales) and Parasitoids (Hymenoptera: Braconidae and Encyrtidae) on Irrigated Spring Wheat in Southwestern Idaho
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DOI：
10.1093/ee/20.6.1699
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发表时间：
1991-12
影响因子：
1.7
通讯作者：
M. Feng;James B. Johnson;S. Halbert
中科院分区：
文献类型：
--
作者：
M. Feng;James B. Johnson;S. Halbert
本文报道了美国爱达荷州西南部沟灌春小麦上昆虫寄生真菌和膜翅寄生蜂对玉米蚜虫（Mordvilko）、Metopolophium dirhodum （Walker）和Sitobion avenae （F.）的自然防治情况。涉及的重要真菌是潘多拉neoaphidis (Remaudire & Hennebert) Humber和Conidiobolus spp.，包括C. obscurus (Hall and Dunn) Remaudire、C. thromboides Drechsler和C. coronatus (Constantin) Batko。1986-1989年期间，黄颡鱼种群数量通常达到或超过经济水平。noxia直到1987年6月下旬才进入该地区。这是1988年发现的第一种蚜虫，在那个夏天达到了高密度，但1989年没有被发现，可能是因为在一个极端寒冷的冬天死亡。M. dirhodum、S. avenae和D. noxia分别在作物定殖后的第2、3和6周发生真菌感染。动物流行病每年夏季发生，但通常发生在作物被大量蚜虫破坏之后。1987年出现了一个例外，当时真菌有效地抑制了白僵菌和绿僵菌的种群，但5月下旬和6月异常频繁的降雨明显增强了它们的种群数量。因真菌感染而导致的死亡率高于S. avenae和D. noxia。病原菌以新蚜虫为优势菌，孢子虫为主要菌。嗜色虫疫霉Burger & Swain和两种疫霉偶发感染谷类蚜虫。拟寄生物，主要是蚜虫对燕麦蚜虫的攻击时间早于真菌，对稻谷蚜虫的攻击时间早于真菌对稻谷蚜虫的攻击时间，但对寄主种群减少的影响较小。多元回归和相关分析表明，与作物成熟的影响相比，真菌和拟寄生物对各蚜虫高峰种群的减少贡献显著。真菌感染与寄主密度和气候因子呈弱相关（r2为0.35 ~ 0.53）。真菌感染的发展似乎与寄主密度的关系比与气候因素的关系更好。降水与寄生在寄主作物上部的S. avenae真菌感染的关系更大，而对寄生在更湿润微环境中的M. dirhodum和D. noxia真菌感染的影响较小。其他气候因子与真菌感染无显著相关。提出了一种假设，即小麦植株上典型的蚜虫占据的位置影响真菌病的发展。
Data on the natural control of cereal aphids, Diuraphis noxia (Mordvilko), Metopolophium dirhodum (Walker), and Sitobion avenae (F.), by entomophthoralean fungi and hymenopterous parasitoids on furrow-irrigated spring wheat in southwestern Idaho are presented. The important fungi involved were Pandora neoaphidis (Remaudire & Hennebert) Humber and Conidiobolus spp., including C. obscurus (Hall and Dunn) Remaudire, C. thromboides Drechsler, and C. coronatus (Constantin) Batko. During 1986–1989, M. dirhodum and S. avenae populations usually reached or exceeded economic levels. D. noxia did not enter the region until late June 1987. It was the first aphid found infesting the crop in 1988 and reached high densities that summer but was not found in 1989, perhaps because of mortality during an extremely cold winter. Fungal infection occurred ≍2,3, and 6 wk after colonization of the crop by M. dirhodum, S. avenae , and D. noxia, respectively. Epizootics occurred each summer but usually after the crop was damaged by large aphid populations. An exception occurred during 1987 when M. dirhodum and S. avenae populations were effectively suppressed by mycoses, apparently enhanced by unusually frequent rainfall during late May and June. M. dirhodum experienced much higher mortality from fungal infection than did S. avenae and D. noxia. P. neoaphidis was the dominant fungus infecting M. dirhodum and D. noxia, whereas Conidiobolus spp. were most important on S. avenae. Entomophthora chromaphidis Burger & Swain and two Zoophthora species sporadically infected cereal aphids. Parasitoids, mainly Aphidius ervi Haliday for S. avenae and M. dirhodum and Diaeretiella rapae (M'Intosh) for D. noxia, usually attacked cereal aphids earlier than the fungi but were less influential during the decline of host populations. Multiple regression and correlation analysis indicated that mycoses and parasitoids made significant contributions to the reduction of peak populations of each aphid species compared with the influence of crop maturation. Weak correlation between fungal infection and host density and climatic factors ( r2 ranging from 0.35 to 0.53) was found. Development of fungal infection seemed to be better correlated with host density than with climatic factors. Precipitation was more associated with fungal infection of S. avenae, which inhabits upper portions of the host crop, but had little effect on that of M. dirhodum and D. noxia, which inhabit more humid microenvironments. No other climatic factors were significantly correlated with fungal infection. A hypothesis is proposed that the site on a wheat plant typically occupied by an aphid species influences the development of mycoses.