HABITAT-SPECIFIC PARASITISM OF THE STALK BORER (LEPIDOPTERA, NOCTUIDAE) IN NORTHERN OHIO

Larvae of the stalk borer, Papaipema nebris (Guenée), collected from corn, potatoes, and giant and common ragweed in northern Ohio were reared to pupation to determine parasitism. Parasitoid complexes were dominated by Lixophaga thoracica (Curran) (Tachinidae) in corn (78.3% of the total parasitoids); Sympiesis viridula (Thompson) (Eulophidae), an introduced parasitoid of European corn borer, Ostrinia nubilalis (Hübner), in potatoes and associated common ragweed (62.9%); and Lissonata brunnea (Cresson) (Ichneumonidae) and Gymnochaeta ruficornis Williston (Tachinidae) in giant ragweed (96.3%). Percentage of parasitism by G. Ruficornis was positively correlated with stalk borer density; with L. Brunnea the correlation was negative. This study demonstrates the importance of host habitat for several parasitoids of the stalk borer. © 1990 Entomological Society of America.