苏云金杆菌菌株Bti99-11的研究

通过物理、化学诱变筛选获得一株对蚊幼高毒的Bt菌株,编号为99-11。该菌具有苏云金杆菌以色列亚种(H14)的典型特征。生理生化特性和培养特征与已知的H14以色列亚种略有差异,血清型与以色列亚种完全一致,但对蚊动的毒力却明显高于对照菌株。     

The development of integrated pest management for the control of mushroom sciarid flies,Lycoriella ingenua (Dufour) and Bradysia ocellaris (Comstock), in cultivated mushrooms

Mushrooms are susceptible to a range of diseases and pests that can cause serious crop loss. Effective pest and pathogen control is a very important factor for the maintenance of efficient production of cultivated mushrooms. Integrated pest management in mushrooms is reliant upon four main principals/elements: sanitation, exclusion, monitoring and pest control. Bradysia ocellaris (Comstock) and Lycoriella ingenua (Dufour) (Diptera: Sciaridae) are major pests of cultivated mushrooms, Agaricus bisporus (Lange) Imbach. These pests cause losses in yield through larval damage of the compost, mycelium and sporophores, and affect the structural features of the compost itself. Adult flies of these species also act as vectors for the introduction of mites and fungal diseases in cultivated mushrooms. Copyright © 2010 Society of Chemical Industry     

Bti菌液对古田山多菌蚊室内毒力测试及药效研究

阐述了苏云金杆菌以色列变种（Bti）的生物活性，将Bti在食用菌双翅目古田山多菌蚊的幼虫作毒力测定和药效研究。试验结果表明，室内毒力测试4g／LBti菌液对古田山多菌蚊幼虫24h药效达59％，大棚药效试验中1．5g／L、2g／L的Bti菌液药后11d药效达到90％以上，持效期16d以上：     

High level methoprene resistance in the mosquito Ochlerotatus nigromaculis (Ludlow) in central California

In the summer of 1998, failures of methoprene field applications to control the mosquito Ochlerotatus nigromaculis (Ludlow) were noticed in several pastures in the outskirts of Fresno, California, USA. Effective control with methoprene had been achieved for over 20 years prior to this discovery. Susceptibility tests indicated that the Fresno Oc nigromaculis populations had developed several thousand‐fold higher LC₅₀ and LC₉₀ tolerance levels to methoprene compared with methoprene‐naïve populations. The synergists piperonyl butoxide (PBO), S,S,S‐tributyl phosphorotrithioate and 3‐octylthio‐1,1,1‐trifluoro‐2‐propanone had little synergistic effect, suggesting that the mechanism of methoprene tolerance was not mediated by P450 monooxygenase or carboxylesterase enzyme degradation. As part of initiating a resistance management strategy, partial reversion back to methoprene susceptibility was achieved in a resistant population after six consecutive applications of Bacillus thuringiensis israelensis Goldberg & Marga coupled with two oil and two pyrethrum + PBO applications. © 2002 Society of Chemical Industry     

Persistence of Bacillus thuringiensis israelensis (Bti) in the environment induces resistance to multiple Bti toxins in mosquitoes

BACKGROUND: The simultaneous production of six different toxins by Bacillus thuringiensis israelensis (Bti) is thought to delay the evolution of resistance in treated mosquito populations. Recent studies have shown that Bti can persist and proliferate in the environment, thereby imposing continuous selective pressure on mosquito populations, raising concerns about the long‐term effectiveness of this bioinsecticide. In order to evaluate the effect of Bti persistence on the evolution of resistance, the authors selected a laboratory Aedes aegypti L. strain with field‐collected leaf litter containing Bti toxins. RESULTS: It is shown that resistance to each individual Bti toxin (up to 30‐fold) can be obtained after only a few generations of selection. However, the resistance to commercial Bti and to environmental Bti remains low (twofold and 3.4‐fold respectively) in the selected strain. Furthermore, some selected individuals exhibited resistance to Cry4B but not to Cry4A, suggesting that two distinct resistance mechanisms are involved in the resistance to these two toxins. CONCLUSION: Considering that resistance to Cry toxins might act as a first step to resistance to a complete Bti toxin mixture, the present results highlight the importance of testing each toxin individually in order accurately to monitor Bti toxin resistance evolution in field populations. Copyright © 2010 Society of Chemical Industry