Lydella stabulans var. grisescens (Robineau-Desvoidy)

O. H. Swezey, 1946, SOME MISCELLANEOUS DIPTERA OF GUAM, Insects of Guam-II, Hawaii, Honolulu: Bernice P. Bishop Museum, pp. 195-200 : 196

4. * Lydella stabulans var. grisescens (Robineau-Desvoidy) .

Ceromasia lepida Meigen , Nakayama, Chosen Govt. Agr. Expt. Sta., Ann. 4: 95, 1929.

Ceromasia lepida, Vandenberg , Guam Agr. Expt. Sta., Rept., 1931 -32, 21, 1933.

Lydella grisescens Robineau-Desvoidy , Clark, U. S. Dept. Agric. Tech. Bull. 455: 19, 1934.

LydrJ!lastabulans var. grisescens (Robineau-Desvoidy) , Baker in letter.

This tachinid fly was introduced from Japan into Guam in 1931 by S. R. Vandenberg, as a parasite on the European corn borer, Pyrausta nubilalis. It was first known as Ceromasia lepida Meigen , but later the name Lydella stabulans variety grisescens (Robineau-Desvoidy) came into use in the United ~tates, where the fly had been introduced and become established in the region around the west end of Lake Erie. In 1936, we found that this tachinid was satisfactorily controlling the European corn borer in Guam. Usually only a small proportion of the corn stalks was injured, and the injury was not sufficient to prevent a well-formed ear. Usually about SO percent of the caterpillars found were parasitized, sometimes 80 percent or more. There were one to three tachinid maggots per caterpillar, but more often only one maggot per host was found. This fly was found in all regions where the corn borer was found.