In the long-term chemical pesticide control conditions, pests will develop resistance, and unreasonable use of biological pesticides can also produce resistance. After long-term field application and laboratory tests, the author observed that the bacterial bio-pesticide Bt (Bacillus thuringiensis) is also susceptible to resistance, among which the resistance of Plutella xylostella is up to 540 times, that of cabbage caterpillar is 148 times, and that of cotton bollworm is 102 times.
As the amount and frequency of bio-pesticides continue to increase, the resistance of pests to bio-pesticides will gradually emerge. In addition to the genetic and biological characteristics of pests, the development of pest resistance to biological pesticides is also likely to cause a straight-line rise in resistance. Therefore, in order to delay the resistance of pests to bio-pesticide, first of all, bio-pesticide cannot be considered to be omnipotent. The use of bio-pesticide is pursued blindly, and it cannot be used to replace other pesticides. If vegetable pesticides are used 8-9 times a year in vegetable production, it is easy to create favorable conditions for resistance to Plutella xylostella and Pieris rapae.
How to reduce the resistance of pests to biopesticide Bt. The author believes that the following points should be noted:
1. In rainy areas, it is allowed to use about 2 times in 1 season; in arid areas (average annual rainfall is about 600 ml, the highest year is 800 ml, the lowest year is 300 ml), and 1 cooked once is appropriate. For the control of Plutella xylostella, Bt pesticides are used twice in spring, once in summer and twice in autumn. More than 2 times of poor control, other biological pesticides must be replaced, and low-toxic chemical pesticides should be used if necessary.
Second, microbial pesticides and plant-based pesticides mainly control pests by stomach poisoning. The temperature, humidity, light, wind and rain conditions are stricter. For example, the optimal control temperature of Bt in Jiangsu is 25-34 degrees Celsius, the fungus Beauveria bassiana is about 25 degrees Celsius, and Beauveria bassiana is 23-25 ​​degrees Celsius. In addition, humidity, sunshine and application time should be strictly controlled.
3. After pests are resistant to biological pesticides, they can be mixed with some chemical pesticides. Such as low-toxic ester chemical pesticides to improve its control, but should not be mixed with organophosphorus pesticides.
4. When the Bt pesticide is stored in liquid form, the pH value is adjusted to about 4.6.
5. The inhibitor of multifunctional oxidase can be appropriately added as a biological protective agent, which can improve the efficacy, reduce the dosage and delay the development of resistance.
Sixth, comprehensive prevention and control measures should be adopted to combine biological, physical, agricultural control and chemical control, and the amount and frequency of pesticides should be reasonably controlled to maintain the production safety of agricultural products.
As the amount and frequency of bio-pesticides continue to increase, the resistance of pests to bio-pesticides will gradually emerge. In addition to the genetic and biological characteristics of pests, the development of pest resistance to biological pesticides is also likely to cause a straight-line rise in resistance. Therefore, in order to delay the resistance of pests to bio-pesticide, first of all, bio-pesticide cannot be considered to be omnipotent. The use of bio-pesticide is pursued blindly, and it cannot be used to replace other pesticides. If vegetable pesticides are used 8-9 times a year in vegetable production, it is easy to create favorable conditions for resistance to Plutella xylostella and Pieris rapae.
How to reduce the resistance of pests to biopesticide Bt. The author believes that the following points should be noted:
1. In rainy areas, it is allowed to use about 2 times in 1 season; in arid areas (average annual rainfall is about 600 ml, the highest year is 800 ml, the lowest year is 300 ml), and 1 cooked once is appropriate. For the control of Plutella xylostella, Bt pesticides are used twice in spring, once in summer and twice in autumn. More than 2 times of poor control, other biological pesticides must be replaced, and low-toxic chemical pesticides should be used if necessary.
Second, microbial pesticides and plant-based pesticides mainly control pests by stomach poisoning. The temperature, humidity, light, wind and rain conditions are stricter. For example, the optimal control temperature of Bt in Jiangsu is 25-34 degrees Celsius, the fungus Beauveria bassiana is about 25 degrees Celsius, and Beauveria bassiana is 23-25 ​​degrees Celsius. In addition, humidity, sunshine and application time should be strictly controlled.
3. After pests are resistant to biological pesticides, they can be mixed with some chemical pesticides. Such as low-toxic ester chemical pesticides to improve its control, but should not be mixed with organophosphorus pesticides.
4. When the Bt pesticide is stored in liquid form, the pH value is adjusted to about 4.6.
5. The inhibitor of multifunctional oxidase can be appropriately added as a biological protective agent, which can improve the efficacy, reduce the dosage and delay the development of resistance.
Sixth, comprehensive prevention and control measures should be adopted to combine biological, physical, agricultural control and chemical control, and the amount and frequency of pesticides should be reasonably controlled to maintain the production safety of agricultural products.
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