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自1973—1974年以来,在湖北荆州地区微生物站筛选出一批棉铃虫病毒毒株,其毒力均为80％以上,有的高达100％。其中毒力较强而又比较稳定的VHA-273,经病虫组织切片观察,确定其为核多角体病毒。1974—1975年除对棉铃虫病毒病的组织病理变化作了初步观察外,又继续在室内外对病毒的毒力、剂量与虫龄、温度的关系,及寄主饲料对病毒产量的影响等,进行了一系列的试验,并用VHA-273生产部分病毒,为大田防治试验作了准备。 1975年7—9月,用VHA-273生产的病毒,在湖北公安县雷州公社约102亩的早发棉田进行示范试验,对第2代及第4代棉铃虫的防治效果,先后调查了5次,最后对试验田、对照田及邻田又作了天敌调查,结果均表明试验田的虫口下降率,花、蕾及青铃受害率等,均低于1605+DDT及西维因的对照田,为棉田的生物防治提供了有希望的微生物农药。 VHA-273棉铃虫核多角体病毒,对烟青虫的毒力很强,对两种害虫能交叉感染。因此,它可用于烟青虫的防治。
Since 1973-1974, a number of strains of cotton bollworm strains have been screened at the microbial station in Jingzhou, Hubei Province. Their virulence is above 80% and some up to 100%. VHA-273, which is more virulent and stable, was observed by pest tissue sections and identified as a nuclear polyhedrosis virus. In addition to preliminary observations on the histopathological changes of the cotton bollworm virus disease from 1974 to 1975, the author continued to study the relationship between the indoor and outdoor virulence of the virus, the relationship between dose and worm age and temperature, and the effect of host feed on the virus yield. A series of experiments were carried out and some of the viruses were produced using VHA-273 to prepare for field control trials. From July to September 1975, the virus produced by VHA-273 was used to conduct demonstration experiments in early-onset cotton fields of about 102 mu in Leizhou commune, Gong’an County, Hubei Province. The control effects of the second and fourth generations of cotton bollworm were investigated 5 Times. At last, the natural enemies were also investigated in the experimental field, the control field and the neighboring fields. The results showed that the drop rates of insects, the buds of flowers, the buds and the green bell were all lower than the control fields of the 1605 + DDT and the western medicine. The biological control of cotton provides promising microbial pesticides. VHA-273 Helicoverpa armigera polyhedrosis virus, the toxicity of tobacco budworm is very strong, the two pests can cross-infection. Therefore, it can be used for the control of tobacco budworm.