Effects of the Fungus Lagenidium giganteum Couch on Mosquitoes

Abstract

Culex guinquefasciatus Say was used as a control organism in a study to determine if Lagenidium giganteum Couch was pathogenic to second-third instar larval stages of the mosquitoes Psorophora columbiae (Dyar & Knab) and Anopheles quadrimaculatus Say. This was done by homogenizing varying sections of sporulating agar plate cultures of Lagenidium in one liter of distilled water and spraying these one liter mixtures into pans containing second-third instar larvae of the three mosquito species. This study also attempted to find the concentrations of Lagenidium needed to give high larval mortality in the laboratory for all three mosquito species. Mortality induced by Lagenidium on all three species was erratic, and the concentrations needed to give high mortality for the mosquitoes were not determined. Psorophora and Anopheles were found to be susceptible to Lagenidium infections, and Anopheles was able to propagate the parasite. A preference test conducted with Lagenidium zoospores indicated that the zoospores are attracted to mosquito larval food.