What are the precautions for applying bacterial pesticides?

Bacterial pesticide is a biological control method. At present, bacterial pesticides are widely used in the control of flower and tree pests, with the advantages of high control effect, no pollution and no residual poison. Bacterial pesticides are living preparations, and their insecticidal principle is that bacteria multiply after entering insects, producing toxic companion crystals, disturbing the normal physiological metabolism of pests and causing them to die. It is different from the insecticidal principle of chemical pesticides, and improper use will reduce the efficacy or even be completely ineffective.

Bacterial pesticides include: bacterial pesticides and bacterial fungicides. At present, there are more than 100 kinds of bacterial pesticides, mainly Bacillus thuringiensis, Japanese scarab and bacillus sphaericus. Bacterial fungicides include Gram-negative bacteria and Gram-positive bacteria, mainly Pseudomonas fluorescens and Bacillus.

Bacterial pesticides are characterized by strong selectivity, safety to people and animals, high environmental compatibility, generally safety to natural enemies of pests, difficulty in producing resistance, easy cultivation, short cultivation time, simple production process, strong stress resistance, easy storage and transportation, and lower development and registration costs than chemical pesticides.

Bacterial pesticides are biological agents, and the insecticidal effect is related to the number and activity of bacteria. When using, the meteorological conditions are strict, and the following matters must be paid attention to.

1. temperature: the suitable temperature is above 20℃. If the temperature is low, the active spores of bacterial pesticides reproduce slowly in pests, and the active proteins are not easy to play their roles. According to the test, the drug effect at 25-30℃ is twice as high as that at 12- 15℃.

Humidity: The greater the environmental humidity, the higher the efficacy, especially the use of powdery bacterial pesticides. The main reason is that the spores of bacteria are not dry. Therefore, the use of powdery bacterial pesticides should be carried out in the morning and evening when there is dew, so that bacteria can better adhere to the stems and leaves of crops, promote spore reproduction and increase the chance of contact with pests.

3. Sunlight: Ultraviolet rays in sunlight can kill spores. After 30 minutes of direct sunlight, spores will die by 50%, and after 1 hour, the mortality rate is as high as 80%. In addition, ultraviolet irradiation can also deform parasporal crystals and reduce their effect. Therefore, it is appropriate to apply pesticide after 4 pm or on cloudy days.

4. Rain: Heavy rain will reduce the efficacy after application, but rain in Mao Mao will increase the efficacy 5 hours after application. Rain in Mao Mao will promote spore activity, thus accelerating the death of pests. Therefore, the use of bacterial pesticides should be combined with the local weather forecast to ensure that there is no moderate rain or heavy rain within 1-2 days after application. In case of heavy rain after application, apply the pesticide immediately after the rain; At this time, the effect of supplementary application is better.

5. The suitable temperature for spraying bacterial and microbial pesticides is 20-30℃, mainly because the active and effective components of this kind of pesticides are protein crystals and live spores. At low temperature, the reproduction speed of spores in pests is extremely slow, and protein crystals are not easy to produce effects.

Six, the application of bacterial biological products pesticides, the greater the relative humidity of the air, the higher the efficacy, especially for powdery biological products pesticides. Because the spores of bacteria are not resistant to the natural environmental standards of drying, so? Spraying bacteria particles should be carried out in the morning and evening under the condition of dew, so as to facilitate the bacterial agent to adhere to the basal leaves well, promote spore reproduction and enhance drug efficacy.

Seven, after 5 noon or rainy days, the use of biological pesticides, ultraviolet rays in the sun can destroy spores. The lethal rate of spores reached 50% after 30 minutes of sunlight irradiation and 80% after direct irradiation 1 hour.

Eight, heavy rain will lead to the reduction of the efficacy of bacterial pesticides. Moderate to heavy rain will wash away the bacterial liquid scattered on the leaves and reduce the efficacy. But if you spray for 5 hours, it is not easy to reduce the control effect, but it has the effect of improving quality and increasing efficiency.

The above are common problems in the application of bacterial pesticides. Everyone should pay attention to the above problems when applying bacterial pesticides, and pay attention to the conditions and time of drug use.