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在生产实践中,苏云金杆菌(Bacillus thuringiensis,简称B.t)的自然衰退现象普遍存在。前几年,由于有些厂家到处引种,以致使一些退化菌种用于生产。用退化菌种生产的菌剂,虽然含活孢子数达到了标准,但晶体率不高,杀虫毒力差,严重影响了B.t制剂的信誉。经过昆虫连续传代是菌种提纯复壮的有效措施之一。盛祖嘉等认为,通过虫体传代可以恢复和提高菌种毒力,即所谓“虫体复壮”。日本吉川等曾将B.t.Berl的一个菌株通过斜纹夜蛾作传代试验,发观经过6次传代后细菌在虫尸内增殖良好。在我国,幸兴球等用B.t的6个菌株通过粘虫虫体复壮后,发现所有试验菌株在经
In the production practice, Bacillus thuringiensis (B.t.) natural decay phenomenon is ubiquitous. A few years ago, due to the introduction of some manufacturers everywhere, so that some of the degenerative strains for production. Bacteria produced by the degenerative species, although the number of viable spores reached the standard, but the crystal rate is not high, insecticidal toxicity, seriously affecting the credibility of B. t preparations. After the continuous passage of insects is one of the effective measures to purify and rejuvenate bacteria. Sheng Zujia think, through the passage of parasites can restore and enhance the strains of virulence, the so-called “rejuvenation.” Japan’s Yoshikawa once B.t.Berl a strain of Spodoptera litura passed through the passage of time, after 6 generations of germination germs in insect body proliferation well. In our country, Xing Xingqiu and other strains of B.t. by the armyworm rescued by the armyworm and found that all the test strains in the