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The European corn borer on Long Island

Dohanian, S.M.
Psyche 1934 v.41 no.4 pp. 214
Ostrinia nubilalis, boring insects, Zea mays, corn, strain differences, univoltine habit, multivoltine habit, overwintering, population density, host plants, parasitoids, biological control agents, geographical distribution, insect surveys, New York
Pyrausta nubilalis [Ostrinia nubilalis], Hb., was first discovered on Long Island in 1923, when larvae of the one-generation strain were found at the extreme west. This strain spread eastward at an average rate of 4 miles a year during the following 10 years. Control measures, the comparative scarcity of hibernating quarters owing to the absence of field maize, and the fact that this form rarely attacks weeds, probably account for the slowness of spread. In 1927, the two-generation strain was discovered at the extreme east, from which it spread westwards almost twice as rapidly. The two strains now occur together over an area of about 275 sq. miles to the west of the centre of the Island. Annual surveys of the populations showed that the one-generation strain increased slowly but steadily during 1928-33. During 1931 there was a marked increase of the two-generation strain. A list is given of the 23 plants attacked on Long Island. Maize is the only crop that is affected commercially, but potato is important as a reservoir of infestation, and the insect may be introduced into uninfested areas in the pods of lima beans. The abundance of the two-generation strain and its practical isolation from neighbouring infested areas presented an excellent opportunity to ascertain the value of biological control. During the summer of 1933, 67, 435 individuals of 16 species of introduced parasites, including some of those already noticed [R.A.E., A 16 273; 22 114; 23 247], as well as Omorgus (Campoplex) multicinctus, Grav., O. (C.) pyraustae, Smith, Phaeogenes nigridens, Wesm., and Zenillia mitis, Mg., were liberated.