Co-Authors:
Gindin, G., Dept. of Entomology, ARO, Volcani Center, Bet Dagan, Israel
Navon, A., Dept. of Entomology, ARO, Volcani Center, Bet Dagan, Israel
Saphir, N., Forest Department, Land Development Authorities, JNF, Eshta'ol, Israel
Protasov, A., Dept. of Entomology, ARO, Volcani Center, Bet Dagan, Israel
Mendel, Z., Dept. of Entomology, ARO, Volcani Center, Bet Dagan, Israel
Abstract:
Information on persistence of Bacillus thuringiensis (Bt) is needed to improve the microbial pest management programs against the pine processionary moth Thaumetopoea wilkinsoni in pine forests in Israel. The persistence of the microbe under natural conditions of rain and sunlight was evaluated and is documented here for the first time. Pine saplings were sprayed with three commercial Bt products, Foray 48B, Delfin WG and Dipel DF, all used at 32,000 IU mg-1 in a formulation with 1% (w/v) of condensed milk. In experiments conducted in November and December of 2004, the saplings were either exposed to rain and sunlight or were sheltered to avoid these environmental factors. The lowest rainfall recorded in the 8-day experiments was 16.5 mm (test 2) and the heaviest was 71.1 mm (test 1). Solar irradiation ranged from 9.4 to 10.9 MJ m-2. The minimum temperature was close to 10deg;C and the maximum was less than 23°C. Needles of the treated saplings and their controls were sampled after 0, 1, 5 and 8 days, and were fed to 1st or 2nd instar larvae. Dipel DF persisted better than Delfin WG and still retained its initial activity of 80-100% mortality on day 8 at low rainfall (test 2). Dripping of Bt from upper to lower branches was quantified with the larval bioassays. The milk formulation proved to be an effective rain-fasting adjuvant.
תפריט נגישות
ניגודיות עדינה
מונוכרום
הדגשת קישורים
חסימת אנימציה
פונט קריא
סגור
איפוס הגדרות נגישות
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