Efficacy of Entomopathogenic Nematodes Steinernema feltiae and Heterorhabditis bacteriophora against the Melon Aphid (Aphis gossypii Glow., Hemiptera, Aphididae)

摘要

This study was aimed to determine the efficiency of biological control of entomopathogenic nematodes Steinernema feltiae and Heterorhabditis bacteriophora against the melon aphid (Aphis gossypii) in the laboratory conditions. Prior to conducting the trial on entomopathogenic nematodes, their cultivation occurred in an incubator at 24-25~0C on last-instar large wax moth (Galleria mellonella) larvae according to a procedure described by Kaya and Stock (1997). The suspensions obtained as a result of cultivation were kept in a refrigerator at 4-6~0C. Acclimation of nematodes proceeded at room temperature 24-25~0C. The application of the obtained biomass was possible after 6-10 hours. For determination of the efficiency of S.feltiae and H.bacteriophora under room temperature at 24-25~0C and 75% humidity, last instar-imago of the pest was used for trial. Mortality rate of individuals was determined by Abbott formula. The trials were conducted on 10 cm Petri dishes. The obtained results have shown that the nematode S.feltiae is more effective against A.gossypii than H.bacteriophora and 500 nematode/ml suspensions mortality depended on time, nematode variety and concentration. Pest mortality was tested for treatment after 3,5, 7 days. On the 7th day after treatment with a nematode suspension 500,1000,1500 infective juveniles/ml of S.feltiae in the given trial reveal 20, 58 and 78% mortality rate whereas H.bacteriophora 15,28, and 46% respectively. The obtained results show that under laboratory conditions the efficiency of S.feltiae and H.bacteriophora against A.gossypii can be controlled lay S.feltiae rather than H.bacteriophora and therefore, future study is to be conducted in greenhouse and field conditions.