Weeds adjacent to commercial tomato production fields on the west coast of Florida were surveyed during 1982–1983 to determine which species serve as reservoirs of Agromyzidae leaf miners and their parasitoids. About 95% of the leafminer larvae were observed in foliage of seven weed genera (Solanum americanumMill.,Erechtites hieracifolia(L.),Bidens alba(L.),Gnaphaliumspp.,Physalisspp.,Sonchusspp., andRumex obtusifoliusL.) and volunteer tomato even though these species accounted for only about 13–42% of the weed canopy.Liriomyza trifolii(Burgess) andL. sativaeBlanchard accounted for 45 and 40%, respectively, of the leafminer adults reared from infested foliage and were most prevalent fromS. americanumandB. alba. The larval–pupal parasitoidsOptus dissitusMuesebeck,Oenonogastra microrhopalae(Ashmead), andHalticoptera circulus(Walker) were the most abundant leafminer parasitoid adults reared from leafminer infested foliage, accounting for 37.8, 15.1, and 15.8%, respectively, of the total reared. The larval parasitoidsNeochrysocharis punctiventris(Crawford),Diglyphus begini(Ashmead), andD. intermedius(Girault) accounted for 8, 5, and 2.5%, respectively.