Submitted to: Environmental Entomology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 9/1/2001
Publication Date: 6/1/2002
Citation: FERREIRA, M.A., GEDEN, C.J., BOOHENE, C.K., BECNEL, J.J., PIRES DO PRADO, A. MICROSPORIDIOSIS OF TACHINAEPHAGUS ZEALANDICUS ASHMEAD (HYMENOPTERA: ENCYRTIDAE). ENVIRONMENTAL ENTOMOLOGY. 2002. Interpretive Summary: Parasitic wasps are important tools for managing house flies and stable flies on livestock and poultry farms. Wasp releases can reduce fly populations and save farmers money while reducing the amounts of insecticides needed for their fly control programs. To meet the demand for these biocontrol agents by American farmers, several commercial insectaries snow produce and sell wasps for farmers to release. The quality and effectiveness of these commercially-produced wasps is significantly compromised if they are infected with protozoan parasite in the genus Nosema. In this study, scientists at USDA's Center for Medical, Agricultural and Veterinary Entomology (Gainesville, FL) and the University of Campinas (Brazil) discovered a new Nosema disease infecting a species of wasp (Tachinaephagus zealandicus) that attacks flies when they are still in the larval stage. The disease is transmitted from mothers to their offspring, and is spread among larvae when infected and uninfected wasp larvae share the same fly host. A drug test determined that disease transmission from mothers to progeny can be interrupted by allowing the parasitoid mothers to feed on honey treated with the antibiotic rifampicin. A clean colony was established from family lines of uninfected females after drug treatment.
Technical Abstract: An undescribed microsporidium was found infecting Tachinaephagus zealandicus, a gregarious parasitoid that attacks third instar larvae of muscoid flies. Spores were present in all body regions and in all stages of development. Infected adults contained an average of 375,000 spores, and the pathogen was vertically transmitted to progeny. Infected female adults swere fed either rifampicin or albendazole mixed with honey to determine th effectiveness of these drugs in preventing vertical transmission. After 8 days of feeding on rifampicin the parasitoids produced progeny that were only 37 percent infected. In contrast, albendazole-treated and untreated females produced progeny that were 97 percent and 100 percent infected, respectively. Healthy and infected colonies were established and studies were conducted to determine the mechanisms of transmission. It was observed that the efficiency of vertical (maternal) transmission was 96.3 percent. Uninfected parasitoid immatures also became infected when they shared superparasitized hosts with infected immatures. The method of transmission within superparasitized hosts is not known.