BIOLOGICALLY BASED MANAGEMENT OF INVASIVE INSECT PESTS AND WEEDS
Location: Insect Behavior and Biocontrol Research Unit
Title: Laboratory biological parameters of Trichogramma fuentesi (Hymenoptera:Trichogrammatidae), an egg parasitoid of Cactoblastis cactorum (Lepidoptera:Pyralidae)
Submitted to: Florida Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 11, 2011
Publication Date: March 1, 2012
Citation: Paraiso, O., Hight, S.D., Kairo, M., Bloem, S., Carpenter, J.E., Reitz, S.R. 2012. Laboratory biological parameters of Trichogramma Fuentesi (Hymenoptera: Trichogrammatidae), an egg parasitoid of Cactoblastis Cactorum (Lepidoptera: Pyralidae). Florida Entomologist. 95(1):1-7.
Interpretive Summary: The Argentine cactus moth continues to damage prickly pear plants in the southeastern U.S. Continued spread of this insect has raised concerns about this moth’s unavoidable and unwanted impact on native, agricultural, and ornamental cactus in its new homeland. A tiny wasp was found in Florida that attacks the eggs of this cactus moth. Scientists with USDA Agricultural Research Service, Center for Medical Agricultural and Veterinary Entomology, Gainesville, Florida, Animal and Plant Health Inspection Service, and Florida A&M University are looking into ways to control the cactus moth, including natural enemies such as the egg-attacking wasp. The female wasp lays her eggs inside the moth egg and the wasp offspring develop by feeding on the moth egg. Studies were conducted to assess biological parameters of this wasp under laboratory conditions. Adult wasps lived longest when fed pure honey, an average of 11 days. Even though female wasps laid eggs if they were not mated, mated females laid more eggs than unmated females, and mated wasps that were two to three days old laid the most eggs. Female wasps preferred to attack moth eggs that were one and two days old, although they attacked moth eggs up to 13 days old. These wasps have been used in other programs to help control moth pests by mass rearing and releasing them in specific locations. If this wasp were to be used in a program to control the cactus moth, then honey should be fed to the mass reared wasps, young (two to three day old) mated wasps should be released, and releases timed to coincide with newly laid cactus moth eggs.
Trichogramma fuentesi Torre was identified attacking Cactoblastis cactorum (Berg), a serious pest of Opuntia spp. in North America, raising the possibility of using this egg parasitoid as an inundative biological control agent. Studies were conducted to assess the biological parameters of this parasitoid under laboratory conditions. Nutritive quality influence of the rearing supplement on the parasitoid’s longevity, mating, and age was evaluated based on the level of parasitism. The presence and type of food source had a positive impact on female longevity, and female parasitoids given a diet composed of pure honey lived the longest; an average of 11 d. Mated females parasitized a greater number of C. cactorum host eggs than did unmated females. Percent parasitism significantly decreased with female age. Two- to 3-day old female parasitoids had the highest level of parasitism. Two-day old host eggs were the optimal host egg age for parasitization by T. fuentesi. In the context of implementing an inundative biological control program against C. cactorum, two-day old mated and honey fed Trichogramma females should be released to increase level of control.