Submitted to: Environmental Entomology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 11/9/2001
Publication Date: 6/1/2002
Citation: Lauziere, I., Setamou, M., Legaspi, J.C., Jones, W.A. 2002. Effect of temperature on the life cycle of Lydella Jalisco Woodley (Diptera: Tachinidae), a parasitoid of Eoreuma loftini (Dyar)(Lepidoptera: Pyralidae). Environmental Entomology. 31(3):432-437. Interpretive Summary: The most important pest of Texas sugarcane is the Mexican Rice Borer, a moth that invaded from Mexico in the early 1980s. The sugarcane industry in south Texas is found in the economically depressed Lower Rio Grande Valley and grosses about $65 million. As its name suggests, the borer spends much of its life inside the sugarcane stalk where it is protected from weather and insecticides. Farmers in Texas have actually abandoned insecticides as a control measure and accept the loss of $10 to $20 million yearly caused by the borer. Clearly, the damage caused by the Mexican Rice Borer is very significant. As part of a program to study insect controls other than insecticides, scientists now at the Center for Biological Control in Tallahassee, Florida tested the Jalisco fly as a biological control agent. The fly was collected from Mexico where it survives naturally on the rice borer which is not an important pest. Fly maggots crawl inside the stalk in tunnels made by the borer to find the pest. The immature fly then develops as a parasite inside the borer, thus killing it. We conducted laboratory studies to test the effects of temperature on the fly prior to making field releases. Fly development and survival was better at temperatures cooler than those of the Texas sugarcane season and more similar to those in its natural habitat in northern Mexico. Therefore, field releases in Texas should be done early in the growing season when temperatures are still cool for the fly to be most effective.
Technical Abstract: The effect of temperature on development, survival, and adult longevity of Lydella jalisco Woodley (Diptera: Tachinidae), a parasitoid of the Mexican rice borer, Eoreuma loftini (Dyar) (Lepidoptera: Pyralidae), was studied under laboratory conditions. Development times of L. jalisco larvae and pupae decreased with temperatures in the range 15-35°C. However, survival was greater at cooler temperatures similar to those encountered in the parasitoid¿s native habitat; percentage of adult emergence was 62.5% at 20°C compared with 9.5% at 35°C. The lower temperature threshold for development of larvae was 14.5°C, whereas for pupae it was 13.8°C. Adult lifespan was also affected by high temperatures. Adult parasitoids lived 20 to 25 d at temperatures in the range 15-25°C, whereas they lived 4 to 6 d at 35-40°C. For ~10 consecutive hours, temperatures exceeding 30°C prevail in the Lower Rio Grande Valley of Texas during the months of May through September when populations of E. loftini reach an economic threshold. Therefore, the potential efficacy of L. jalisco as a biological control agent of E. loftini in south Texas should be examined closely because mated females of L. jalisco require 7-14 d for maximum egg fertilization and embryonic development.