Pyraustanubilalis (Hiibner), 1758

Swezey, O. H., 1946, Lepidoptera, Geometridae, Arctiidae, Agrotidae, and Pyralidae of Guam, Insects of Guam II, Honolulu, Hawaii: Bernice P. Bishop Museum Bulletin 189, pp. 163-185 : 185

42. Pyraustanubilalis (Hiibner) .

Pyralis nubilalis Hubner, Zutr. Samml. Eur. Schm., Pyr. 14: Sechste Horde, 24, 14, fig. 94, 1796.

Pyrausta nubilalis, Meyrick, Handbook Brit. Lep., 416, 1895; Hampson, Fauna Brit. India, Moths 4: 435, 1896; Caffrey and Worthley, U. S. Dept. Agric., Bull. 1476: 1-154, 1,927; Briggs, Guam Agr. Expt. Sta. Rept. (1920), 39, 1921; Vandenberg, Guam Agr. Expt. Sta. Rept. (1930-32), 20, 1933.

Tumon , May 30; Ypan , June 8; Libugon , June 24; Machanao , June 30, Aug. 6; Piti , Aug. 26, Sept. 4, 15; Barrigada, Aug. 28. All collected or reared by Swezey. Three specimens in U. S. National Museum and one in Bishop Museum , Fullaway , 1911.

This moth is the notorious European corn borer, which has become widespread in the United States during the past 20 years. Its distribution is throughout central and southern Europe, Egypt, west-central and northern Asia, northern India, Siberia, Japan, Philippines, and Guam. The first record of it in Guam was by Fullaway in 1911 under the name Pyrausta vastatrix , given by Schultze in Manila , a name which was later recognized as a synonym. It became a very serious pest in Guam , and by 1920 was reported damaging SO percent of the corn crop in some regions. Parasite introduction was attempted in 1926 to 1931. Several kinds of parasites were imported. In 1936 we found that a tachinid, Lydella stabulans var. grisescens Robineau­ Desvoidy, was established and so efficient that very little damage was done to the corn crop by the European corn borer. Whenever we found corn borer larvae in corn stalks, usually SO to 100 percent of them were parasitized. Often in examining the corn borer burrows in corn stalks, the puparia of the parasite would be found, usually one or two and occasionally three per burrow. This tachinid was introduced from Japan by Vandenberg in 1931. At first it was known in Guam reports as Masicera senilis , later as Ceronwsia lepida . In subsequent studies of it, experts in the Tachinidae settled on the n~me Lydella stabulans var. grisescens . One other parasite, Cremastus flavoorbitalis (Cameron)) , introduced from Japan by Vandenberg in 1931 became established in Guam. I reared it from several species of leafroller moths, but not from the corn borer.