Influence of Three Soybean Genotypes on Development of Voria ruralis (Diptera: Tachinidae) and on Foliage Consumption by Its Host, the Soybean Looper (Lepidoptera: Noctuidae)

Abstract

Foliage consumption of three soybean genotypes (`Davis', D75-10230 and ED73-371) by nonparasitized soybean looper (SBL), Pseudoplusia includens (Walker) (Lepidoptera: Noctuidae), larvae and those parasitized by a South American strain of the tachinid, Voria ruralis Fallen, was investigated under laboratory conditions. Although there were no significant (p>0.05) differences among genotypes, parasitized and non-parasitized SBL larvae reared on the commercial cultivar Davis consumed slightly more foliage than those reared on either breeding line D75-10230 or ED73-371, but larvae reared on ED73-371 consumed the least amount of foliage. Parasitized SBL larvae consumed significantly (p =<0.05) less (ca. 40%) foliage than nonparasitized larvae, regardless of the soybean genotype. Mortality of parasitized SBL larvae (before the successful development of V. ruralis) was greatest (90%) on ED73-371 and least (37%) on D75-10230. The mean number of parasitoid puparia per SBL larva was significantly (p=<0.05) less when larvae were reared on ED73-371.