First Record of the Entomopathogenic Fungus Sorosporella sp. (Deuteromycotina: Hyphomycetes) in Locusta migratoria (Orthoptera: Acrididae) from Madagascar: Symptoms of Infection, Morphology and Infectivity

Abstract

In Madagascar, a fungal disease was observed in the migratory locust, Locusta migratoria capito, which was caused by the deuteromycete Sorosporella sp. Multiplication of the fungus in locusts results in the formation of brick-red resting spores filling the body of the insect, and in a pale and fragile cuticle which breaks easily, releasing these spores. The conidia of the fungus (only observed in artificial cultures) are cylindrical in shape, measuring 11.0 2.8 mu m. The growth of the fungus was compared on several solid and liquid media, but was invariably slow. The best growth was obtained on a medium containing 3% ground rice, 3% malt extract, 0.3% peptone and 1.5% agar. Attempts were made to initiate artificial infections in L. migratoria migratorioides and Schistocerca gregaria from a laboratory stock. This was carried out by feeding resting spores or through contact with Sorosporella material from agar cultures. However, it rarely resulted in mortalities with typical symptoms. Inoculations by inject...