Efficacy of Beauveria bassiana (Bals.) Vuill. against the tarnished plant bug, Lygus lineolaris L., in strawberries

摘要: Beauveria bassiana has a high insecticidal potential to control the tarnished plant bug, Lygus lineolaris, significant pest of strawberries. Screening experiments showed that L. lineolaris adults were susceptible several B. isolates. Another screening test with Coleomegilla maculata, natural enemy found in strawberries, was also performed order select isolate having lower entomopathogenic impact on this insect. Based data obtained from both insect species and ecozone origin isolates, INRS-IP INRS-CFL isolates selected for further experiments. The LC 50 values these two against 7.8 x 10 5 5.3 conidia/ml, average survival time (AST) 4.46 4.37 days at concentration 1 8 conidia/ml respectively. Results indicated nymphs are During field experiments, using randomized block design four replicates, applied rates (1 11 13 conidia/ha) weekly during period 4 weeks. These multiple applications triggered reduction nymphal populations Twenty-four after first application, difference observed between mean population densities surviving all bassiana-treated plots (less than one per five plants) compared those (four insects plants). experiment, persistence activity viability conidia monitored. results presence viable infective up 6 each application strawberry foliage. Moreover, rate × conidia/ha fruit injuries induced by feeding behaviour plots.