What are the scientific methods for using bacterial biological insecticides?
From rice sowing to the seedling stage, farmers should focus on controlling seed-borne diseases (bakanae disease, rice blast at the seedling stage, white-tip nematode disease, etc.), the small brown planthopper, and the first-generation stem borers. At the rice booting stage, the focus should be on controlling pests and diseases such as the rice planthopper, rice leaf roller, stem borers, ear blast, and rice false smut. At the rice ear stage, the rice planthopper is the main target, along with...
First, avoid using inferior pesticides. To ensure the quality of the pesticides used, purchase them from legitimate manufacturers and pesticide sales outlets to prevent counterfeit and shoddy products, and pay attention to the production date and expiration period of the pesticide as well as proper storage to prevent expiration and loss of efficacy.Second, avoid using them at low temperatures. The active ingredients of bacterial biological insecticides are protein crystals and living spores. Under low-temperature conditions, the spores reproduce slowly inside the pest's body, and the protein crystals do not easily take effect.
Third, avoid dry environments. The bacterial spores in bacterial biological insecticides prefer humid environments, so the higher the field humidity when applying them, the greater the efficacy; this is especially important when spraying powdered biological pesticide formulations. Generally, spray the bacterial powder formulations in the early morning and at dusk when there is dew, so that the bacterial preparation adheres better to the crop stems and leaves and to promote spore reproduction and improve efficacy. Spraying on foggy mornings or watering the vegetables half an hour before spraying gives better results.
Fourth, avoid strong light. Ultraviolet rays in sunlight have a killing effect on spores; if the light is strong, ultraviolet rays will kill the bacteria. According to experiments, after half an hour of direct sunlight, the spore mortality rate reaches about 50%; after 1 hour of direct sunlight, the spore mortality rate reaches 80%. In addition, ultraviolet radiation can deform the parasporal crystals and reduce their efficacy. Therefore, bacterial biological insecticides should be sprayed on cloudy days or in vegetable plots with weak light. Generally, apply the pesticide before 10 a.m. on sunny days or in the evening.
Fifth, avoid heavy rain washing. If moderate to heavy rain occurs shortly after spraying bacterial biological insecticides, it will wash the bacterial solution off the crop stems and leaves and reduce efficacy. However, if light rain falls 5 hours after application, it will not reduce the control effect but instead have a synergistic effect, because this helps the bacterial spores reproduce rapidly inside and outside the pest's body.
Sixth, avoid mixing with fungicides. When applying bacterial biological insecticides, never mix them with fungicides (such as carbendazim, thiophanate-methyl, etc.), otherwise it can easily cause a serious reduction in the number of bacteria in the pesticide, thereby affecting the insecticidal effect. Therefore, even a sprayer that has been used for fungicides must be rinsed clean before being filled with bacterial biological insecticide.