摘要
本文对5株灭蚊幼高效球形芽胞扦菌(B.S)进行了产毒妙能和杀虫活性影响因素的观察,结果表明:2362菌株具有生长周期短,产毒水平高,对不同培养基有较好适应性等优良特性。同时证实我国自行分离的 BS—10、NKⅢ1—1也有较好的开发前途。2362、1593株的毒效积累在孢子囊体(中期)已达高峰,进一步发育芽孢释放后毒效不再继续上升。不同菌株杀虫活性的差异,还表现在持效时间的不同,1593、MR—4、BS10一般可持放5天,而2362在污水中可以持设10天以上,显示2362菌株具有良好的持效。水的污染程度和环境温度影响 B.S 毒效的二个致关重要的因素。一般菌株在高温下(28℃)比低温(18℃)表现更高的杀虫活性,但 MR—4则能适应于较低温度(18℃)。
A comparative study was carried out among 5B.S strains that were highly effective in mosquito la-rvae elimination.The results showed that:(1) The strain 2362 had the characttericics such as shorterculture period,high toxigenicity and good adaptib-ility to different media.It was at the same timeconfirmed that BS-10 NKⅢ 1-1 isolated in Chinahad good prospect for development.(2) The toxig-enicity of the strains 2362 and 1593 reached the pe-ak when they were accumulated in the sporocysts(the middle period),and it wouldnot rise after thespores were further developed and released.(3)The difference among strains in lethal activity wasreflected in the difference of the length of effecti.ve period.The strain 1598,MR-4 and BS-10 couldkeep effective for 5 days,while 2362 could for ov-er 10 days,better in effectiveness than others,and(4) The severity of water pollution and the evir-onmental temperature were two extremely import-ant factors influercing theioxicity of B.S.Seriousplluotion of water could reduce the toxicity by 91—83%.The influence of temperature was manifestedin prologation of the lethal time.Generally,the st-rains showed higher lethal activity with higher tem-perature (28℃) than with lower temperature (18℃)But MR-4 could adapt to lower temperature (18℃),presenting much higher effectiveness at this degreethan at 28℃.This result revealed for the first timea new characteristic of MR-4,a strain differed fr-omo thers.
