Populations of leafminers (Liriomyza spps) have increased in the Lower Rio Grande Valley of Texas (LRGV) in the past few years, becoming pests on various vegetable crops. Growers fear Liriomyza outbreaks because they exhibit high reproductive rates, attack a wide range of hosts, and can easily develop resistance to many pesticides. Integrated Pest Management practices including conservation of hymenopterous parasitoids can maintain populations of leafminers below economic thresholds. However, in the Lower Rio Grande Valley, little is known of the identity and relative abundances of the Liriomyza complex, their host plants, the parasitoid complex, or the effects of insecticides on leafminers and parasitoids. In order to develop Integrated Pest Management programs for Liriomyza species in the Lower Rio Grande Valley we are conducting an intensive survey to identify the leafminer species found in the area and associated larval and pupae parasitoids on major vegetables. We are also studying the effects of commonly used insecticides on the parasitoid complex in hopes of developing effective integrated approaches for Liriomyza management.