Control measures of diseases and insect pests of pear trees

Pear orchard diseases and insect pests are also one of the very important aspects, in addition to recording the types and hazards of diseases and insect pests, as well as the types, doses, times and techniques of the use of pesticides. How to make rational use of pesticides plays an important role in the prevention and control of diseases and insect pests.

First of all, prescribe the right medicine to the case. Select the most suitable varieties of pesticides to control every kind of diseases and insect pests. Different bacteria and insects respond differently to the toxicity of the same drug. In other words, each pesticide has its own control scope and object, such as strychnine can effectively control pear rust and powdery mildew, but the control effect on scab and other diseases is very poor. Imidacloprid has a significant effect on controlling aphids and planthoppers in piercing mouthparts, but it has no effect on mites. Deltamethrin has a good effect on the control of pear heart borer, aphids, pear planthopper and all kinds of caterpillars, but not on mites.

In addition, there were differences in sensitivity to pesticides in different periods of the disease infection process. At the stage of sprouting and invading pear trees, the spores of pathogens are more sensitive to insecticides, and the control effect is better; when the pathogens have invaded the fruit trees and established a parasitic relationship, and the fungi develop into hyphae, the drug resistance is enhanced and the control effect becomes worse. after growing into a fruiting body, it is more difficult to control, such as pear rust. Therefore, the prevention and control of diseases should be mastered before or at the initial stage of the disease.

Secondly, accurate drug use, the correct drug concentration refers to the rarest concentration that can effectively control diseases and insect pests, and does not cause drug damage to pear trees. If we blindly increase the concentration of drugs, it will cause a waste of chemicals, and it is easy to cause resistance to diseases and insect pests. At the same time, there may be pear tree drug damage, human and animal poisoning, causing pollution to the fruit and the environment; too thin can not achieve the purpose of prevention and control. There are many methods for the use of pesticides, and the correct method should be selected according to the harm characteristics of the control objects and the characteristics of pesticide varieties and dosage forms. Such as EC, wettable powder, gel suspension, water agent, soluble powder can be diluted with water spray; powder and granule can not be sprayed with water. And the spray should be from the inside to the outside, from top to bottom, can not leak spray, can not spray more, with the blade fully wet, and will not form flowing water droplets is appropriate. The dosage is the amount of effective components of pesticides per unit area. In the prevention and control of pear diseases and insect pests, we should not only pay attention to the uniform and thoughtful spraying of branches, stems, leaves and fruits, but also pay attention not to excessive, especially when the temperature is high, the liquid left on the leaves can quickly evaporate water, resulting in an increase in concentration, which may cause drug damage to pear trees.

Thirdly, the safe use of drugs and pesticides, including the safety of people, animals, fruit trees, fruits and natural enemies. In the control of pear orchard pathogens and insect pests, priority should be given to high-efficiency, low-toxicity, low-residue pesticides and biological pesticides, and the use of pesticides should be strictly controlled. It is strictly forbidden to spray pesticides with high toxicity and high residues on fruit trees. At the same time, the pesticides used must have "three certificates" (pesticide registration certificate, production license, production approval certificate, standard number). Before the operation, the drug application personnel should understand the drug performance and the matters needing attention in the safe use of the drug, and make the necessary safety measures.

Finally, it is necessary to protect natural enemies and strengthen the biological control of diseases and insect pests to produce green and pollution-free fruits. In nature, there are many natural enemies of fruit tree diseases and insect pests, including parasitic Trichogramma, golden wasps, predatory ladybugs, lacewings, Bacillus thuringiensis, Beauveria bassiana and other microbial natural enemies that cause pests. These natural enemies have strong natural control over diseases and insect pests of fruit trees. We should try our best to protect these natural enemies when using chemicals to control diseases and insect pests.

1. Choose the appropriate application time. The best control period is when the pest has reached the control target or has reached the critical period of control, but the natural enemies have not yet been formed. If there are a large number of natural enemies in the garden, drugs should not be used or selectively used to facilitate natural enemies to control pests. For example, in the early stage of aphid damage, there are few natural enemies and chemical control is applied, but in the later stage, the species and number of natural enemies increase. As long as they do not cause economic harm, pesticides should be used as little as possible to protect natural enemies.

2. Use more internal absorption or selective pesticides and less broad-spectrum or highly toxic pesticides, such as mites, should apply specific and long-term acaricides in the early stage to protect natural enemies. Broad-spectrum pesticides not only control pests but also eliminate natural enemies, and the reproductive ability of natural enemies is weaker than that of pests, so it is easy to lead to the rampant outbreak of insect pests. Choose the appropriate application time. The best control period is when the pest has reached the control target or has reached the critical period of control, but the natural enemies have not yet been formed. If there are a large number of natural enemies in the garden, drugs should not be used or selectively used to facilitate natural enemies to control pests. For example, in the early stage of aphid damage, there are few natural enemies and chemical control is applied, but in the later stage, the species and number of natural enemies increase. As long as they do not cause economic harm, pesticides should be used as little as possible to protect natural enemies.

3. Choose appropriate application methods, such as seizing the opportunity of local occurrence of pests, carrying out selection and control, and reducing the widespread use of pesticides in a large area. For example, the enemy kills frequently in production, because it can kill a variety of pests, but the enemy kills the natural enemies in the pear orchard seriously, continuous and comprehensive use can easily lead to rampant harmful mites.

4. Choose the appropriate pesticide dosage form, the same kind of pesticide has little influence on natural enemies with granules and granules, while EC and powder have great lethal effect on killing enemies. Select appropriate application methods, such as seizing the opportunity of local occurrence of pests, select and control, and reduce the widespread use of pesticides in a large area. For example, the enemy kills frequently in production, because it can kill a variety of pests, but the enemy kills the natural enemies in the pear orchard seriously, continuous and comprehensive use can easily lead to rampant harmful mites.

Points for attention, reasonable mixing. Because many kinds of diseases and pests are often damaged at the same time in a certain life of pear trees, pear farmers often spray more than two kinds of pesticides together according to a certain proportion. But there are strict requirements for the mixed use of pesticides.

The main results are as follows: 1. The action mode and control effect of the same kind of agents are the same, but they can not increase the efficiency and expand the control object, so it is not suitable for mixed use.

2. The effective components of each mixed pesticide must not change after mixing, and the efficacy will not decrease or cause no harm to pear trees after mixing. For example, the mixed use of stone-sulfur mixture and Bordeaux liquid is easy to cause drug damage, and the control effect is also obviously decreased.