BIOCONTROL POTENTIAL OF SOME ENTOMOPATHOGENIC NEMATODES AGAINST STELIDOTA GEMINATA (SAY)

Stelidota geminata (Say) (Coleoptera: Nitidulidae), also known as strawberry sap beetle is considered to be serious pest of strawberry worldwide. All stages of this pest feed on ripe fruitswhich makes its control with chemical insecticides extremely difficult. This work was testing susceptibility of last instar larvae of S. geminata to three, among commercially the most commonly used species of entomopathogenic nematodes Heterorhabditis bacteriophora, Steinernema carpocapsae and Steinernema feltiae (Rhabditida: Heterorhabditidae and Steinernematidae), including two native strains. The present work was carried out through two types of the experiments. First experiment was in plastic Petri dishes with the nematodes applied on filter paper. Second one, in attempt to approach to more natural conditions, effect of the entomopathogenic nematodes on insect's mortality was tested in containers filled with sand. Mortality of S. geminata larvae in Petri dishes in highest nematode concentrations of about 100 infective juveniles per cm(2) was 90%, 82% and 70% for commercial strains of S. carpocapsae, H. bacteriophora and S. feltiae and 76% and 64% for H bacteriophora and S. feltiae native populations. In containers with sand mortality was higher than in Petri dishes and the highest recorded insect mortality with about 50 nematodes per cm(2) was 99.5%, 89%, 75.5%, 69% and 66% with commercial strains S. feltiae, S. carpocapsae and H bacteriophora, and native strains H. bacteriophora and S. feltiae, respectively.