Distribution and Parasitization of Some Lygus Spp. in Western United States and Central Mexico1

Abstract

Lygus hesperus Knight was the predominant species of lygus bugs collected from alfalfa in New Mexico, Arizona, California, Oregon, Washington, and Utah; it was especially abundant in the Southwest. L. elisus Van Duzee, L. desertus Knight, and L. shulli Knight, in that order, were most abundant in northwestern collections, where they occasionally outnumbered L. hesperus . The tarnished plant bug, L. lineolaris (Palisot de Beauvois), occurred sparingly in alfalfa collections from the arid regions of 5 western States. Important wild hosts of L. hesperus and L. elisus in California were winter mustard, sowbane, Russian thistle, and burro weed. Parasitization of Lygus spp. by Leiophron pallipes Curtis was low in several western States, and attempts to establish this parasite in southern California in 1964-65 were apparently unsuccessful. In a limited survey in central Mexico, many specimens of an undescribed Lygus sp. and Proba spp. were obtained from alfalfa and weeds on the high central plateau near Mexico City. Also, weed collections yielded a few L. lineolaris in the State of Michoacan and some Taylorilygus sp. in the States of Morelos and Nayarit. Only 3 braconids (apparently Leiophron sp.) were reared from the collections near Mexico City.