Gedminas, A., Lynikienė, J. and Povilaitienė, A. 2015. Entomopathogenic Fungus Cordyceps militaris: Distribution in South Lithuania, 'in vitro' Cultivation and Pathogenicity Tests. Baltic Forestry 21(2): 359-368 (Brief report)

Cordyceps militaris (L.) Link. is the type species of Cordyceps (Hypocreales, Ascomycetes), which parasitizes larva or pupa of lepidopteran insects. The aim of the present study was to examine: distribution of C. militaris in pine stands of South Lithuania, pathogenicity of the fungus, and optimal conditions for its cultivation in vitro. The efficiency of C. militaris preparations against the pine moth (Dendrolimus pini L.) was tested by artificial infection of hibernating insect larvae in forest litter under natural conditions. During 2010-2011, in pine stands of South Lithuania, a total of 4 % (on areas without pest outbreak) and 59 % (in areas with pest outbreak) of all hibernating insects were infected by C. militaris; meanwhile 99 % of insects damaged by the fungus were D. pini. A massive formation of stromata with fruitbodies of the fungus started at the third year (2011) of outbreak comprising 21% of all larvae infected by the fungus. Stromata with fruitbodies on D. pini larvae were produced after 70 – 80 days of growth under favourable conditions. The optimal conditions for cultivation of C. militaris in vitro were: temperature 18° C, daylight, inoculation with fresh pure culture fragments and cultivation on rice medium. The preparation of C. militaris biocontrol medium for pathogenicity tests was made after 35-40 days after the fungus inoculation on rice medium. Pure culture of the fungus was grown in Petri dish (diameter 9 cm) with medium made of 10 g of rice and 25 ml of distilled water. The mean 6-8 g of dry rice and the fungus mass (biocontrol medium) are possible to get from each Petri dish. The differences of larvae mortality between two treatment methods (spraying and dusting of forest litter with C. militaris preparation, when the larvae were still in crown), and the control, were statistically insignificant. It was estimated that spraying of forest litter with C. militaris preparation increased 3.7 times cordycepsmycosis disease of pine moth larvae, when they already were in forest litter.

Keywords: Cordyceps militaris, impact, infestation, Dendrolimus pini, pests, pine stands