Second, improper application methods Pests and pests have specific hazard parts on the crop, the main focus of spraying should be sprayed. For example, the control of aphids should be directed at the heart leaf spray, and the control of rice planthoppers should be sprayed against the lower part of the rice plant.
Third, the pest resistance continues to increase With the rapid increase in the use of pesticides and the continuous replacement of varieties, pest resistance is increasing, which is a practical problem affecting the full play of pesticides.
Fourth, do not understand the technology, the object of prevention and treatment is not clear. When the disease is attacked, the insects will kill the disease, leading to wrong medication, poor control effect and even phytotoxicity. For example, the soybean field is damaged by weeds, which causes the growth of soybeans to stagnate, but it is treated as root knot nematode disease.
V. Spraying the liquid to waste a large amount of spray equipment commonly used in rural areas of China is a worker-peasant-16 sprayer that has been used for decades. According to the measurement, spray with this sprayer has poor adhesion and low deposition rate, and 70% to 90% of the liquid is wasted.
6. Limitations of Pesticide Self-Controlling Some pesticides have good control effects on certain pests and diseases, but they are extremely ineffective against other pests and diseases. For example, triazophos has better control effects on rice blast, cotton bollworm and other lepidopteran pests, but it can stimulate rice planthoppers to lay eggs, leading to the re-hazard of rice planthoppers.
7. Good grasp at the end of the application time Some insects such as cabbage butterfly, cotton leaf moth, rice blast, etc. like to be harmed during daytime activities with sufficient light, while lepidoptera and some moths are harmful at night. According to the law of pest activity, we can use the medicine in a targeted manner to achieve the best results.
Eight, the constraints of weather conditions Different temperatures, humidity, light, wind, etc. have an impact on the occurrence and prevention of pests and diseases. If the temperature is below 8 °C, the herbicide is not easy to exert its efficacy, and the high temperature and strong light above 35 °C, the chemical pesticides are easy to evaporate and dissipate, and the large liquid liquid drifts and blows away, which also affects the control effect.
First, the timing of medication is not allowed to fight drugs must seize the opportunity, only understand the law of the occurrence of pests and diseases, timely medication, in order to be effective. For example, the treatment of aphids must be used at the peak of egg hatching. If the ants have been stalked into the stalks and then used, the control effect is definitely not good.
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