摘要：In the present study, three isolates of ento- mopathogenic fungus Beauveria bassiana were used for their efficacy on adult rose aphids (Macrosiphum rosae L.) under laboratory conditions. The fungal isolates were obtained from stock cultures at the Phytopathology Laboratory of the Department of Plant Protection at Gaziosmanpasa University, Turkey. Spore suspension was prepared from 30 days old culture of the isolates on PDA medium. The fungal surface was scraped using a sterile glass hokey rod with 10 ml of sterile distilled water having 0.02% Tween 80. Spore concentration was determined using a Neubauer Hemocytometer. Inoculation was performed by spraying spor suspension of the isolates (F-12, F-53, and F-56) at five different concentrations (1x10~4, 1x10~5, 1x10~6, 1x10~7, and 1x10~8 spores/ml) for testing their efficacy on rose aphid adults. Inoculated aphids were transferred on rose shoot (100 mm length) in sterile glass petri dishes (120 mm in diameter) and incubated at 26°C and 70±5% R.H for three days. Control was sprayed with sterile distilled water having 0.02% Tween 80. Then the treated adults were monitored every day for the fungal growth and mortality. The experiments carried out with 3 replications and 20 adults were used for each replication. The results showed that mortality was dose dependent which increased with enhancing the spore concentration of the isolates. The concentration of conidia affected the mortality of aphids significantly (P<0.05). Maximum percent mortality of 66.6% was recorded after 72 h of treatment with a concentration of 1 x 10~8 of isolate F-56; in contrast to this minimum percent mortality of 28.3 was obtained by the application of lowest concentration 1x10~4 of isolate F-12. Mortality rates of the isolates at1x10~8 spores mL-1 concentration were similar. Nowadays, biological control, especially the use of microbial agents, are considered environmentally friendly and safe for non-target organisms. Therefore, B. tassiana isolates can be used to control M. rosae. Further study will be conducted to determine their effects in field conditions.
