Characterization of Lecanicillium lecanii Btab0l Isolated with Bioactivities to Tabacco Whitefly (Bemisia tabaci)

담배가루이(Bemisia tabaci) 병원성곰팡이 Lecanicijjium lecanii Btab0l 균주의 특성

Cultural characteristics Lecanicillium lecani Btab01 and its insecticidal activity against tobacco whitefly (Bemisia tabaci) were investigated. On potato dextrose agar, tryptic soy agar and SDA+Y media, mycelial growth of L. lecani Btab01 was best at $20{\sim}25^{\circ}C$ and suppressed above $28^{\circ}C$. Both solid culture and liquid culture of L. lecani Btab01 showed high insecticidal activity, 93.9 and 98.3% respectively, against nymph of tobacco whitefly, but there is no significant difference. When culture of L. lecani Btab01 was treated at the concentration of $10^5$, $10^6$, $10^7$ and $10^8$ cfu/ml, their insecticidal activity were 5.8%, 33.8%, 77.3% and 98.5% respectively, and $LT_{50}$ values were 16.1 days, 7.3 days, 5.1 days and 3.5 days respectively. When nymphs were treated by the cultures of L. lecani Btab01 and maintained under saturated condition for zero hour, 24 hours and 168 hours, their control activities were 0%, 20.3% and 100% respectively. Spore germination of L. lecani Btab01 was increased about two times by adding edible oil. When L. lecani Btab01 was treated to control nymph with 0.1% edible oil, it showed high control activity(98.6%) compared to single treatment of L. lecani Btab01 (79.9%).

국내에 문제가 되는 담배가루이(Bemisia tabaci)의 살충성 Lecanicillium lecanii Btab01 균주의 생육 특성과 살충력을 검정하였다. PDA, TSA, SDA+Y배지에서 L. lecanii Btab01은 $20{\sim}25^{\circ}C$에서 균사성장이 가장 빨랐으며 $28^{\circ}C$이상에서 성장이 억제되었다. L. lecanii Btab01는 고체배양과 액체배양 시 담배가루이 약충에 대해 살충률에 큰 차이를 보이지는 않았다(93.9%, 98.3%). 농도별로는 $10^5$, $10^6$, $10^7$, $10^8$ cfu/ml에서 각각 5.8%, 33.8%, 77.3%, 98.5%의 살충률을 보였고 각각 16.1일, 7.3일, 5.1일, 3.5일의 $LT_{50}$값을 나타내었다. L. lecanii Btab01을 약충에 처리 후 포화습도 조건을 0 시간 24 시간, 168 시간 유지하였을 때, 0%, 20.3%, 100%의 살충률을 보였다. 균주에 0.5% 식용유를 첨가하였을 때 포자의 발아가 2 배 가량 증가하였으며 균주에 0.1% 식용유를 첨가하여 약충에 처리했을 때(98.6%)가 첨가하지 않았을 때(79.9%)보다 살충력이 향상됨을 알 수 있었다.