How to solve the problems of proper application of pesticides
Appropriate application of pesticides can not only save pesticides, reduce costs, but also improve control effectiveness, reduce drug residues, effectively control the damage of pests and weeds, and ensure the normal growth of crops. In determining the appropriate application period, should consider from the following aspects: Pest period: For pests, pests can be the peak period of egg hatch, larvae, adult emergence period, in which The effect of medication control during the period is most obvious and it depends on the specific circumstances. In principle, it is necessary to grasp the living habits of pests and to carry out the stages that are most likely to kill insects and effectively control the damage. For example, control of armyworm, spraying at the peak of egg hatching, although it has good control effect on hatched larvae, it is not necessarily effective for later hatching larvae, and when the larvae are at the peak of 2 to 3 days, spraying pesticides, a control Can solve the pest problem. In the case of controlling cotton bollworms, newly hatched larvae need to drill into the bells within a short period of time. If they are used again at the peak of larvae at 2 or 3 years of age, the control effect will be poor, and the egg hatches will be used at the peak of hatching. The control effect is particularly significant; the same is true for rice aphids and Spodoptera litura. When pests are controlled, they should generally be used before the peak of the larvae at the age of 2–3 years, and some should be used after the egg hatching peak period. In this case, the application of pesticides can have a multiplier effect. The main reasons are: First, young insects are very thin at the 3rd instar precursor wall, and there are many micro-hairs on the body wall. The epidermis on the micromathematical part is very thin, and the medicine can easily penetrate this layer. , And at this time, the worm body is small, the food intake is large, the harm is light, the activity range is small, and the drug resistance (drug resistance) is weak. Therefore, the appropriate period for determining the pest control should be controlled before the peak of 2-3 years of age, and some It should be used before and after the peak of egg hatching to achieve the best control effect. When the pests reach 4-6 years of age, the food intake and body wall thickness of pests are greatly increased. The thickness of the pests can reach 50-100 times that of the first instar larvae, and the microscopic hair on the body wall is also absent, so that the medicament is not easily adhered. On the body wall and through the body wall, it is difficult to reach the body of the pest, and at the same time, the resistance (resistance) of the insect is also greatly increased, thereby greatly affecting the insecticidal effect of the agent. Second, after the age of pests increases, the amount of fat in the insects also increases, which has the effect of accumulating and decomposing many pesticides. The higher the body fat content of pests, the more obvious this effect is, and the stronger the resistance (resistance) is. Third, the sensitive period of natural enemies: In the period when natural enemies of pests are relatively sensitive to chemical reactions, they should use as little or no medicine as possible to protect their natural enemies and maintain their ecological balance. The fourth is the period of disease-inducing growth: For diseases, the growth period of susceptible diseases is the best suitable period for drug control. Such as the seedling stage most vulnerable to bacterial blight, can be used before sowing seed dressing with fungicides or spray control at seedling stage; again such as the flowering period is the peak period of disease infection, therefore, should be mastered in the flowering period choose to focus on the road agent Prevent and control, control the occurrence and spread of diseases. Fifth, the sensitive period of weeds: Herbicides should generally be applied during the sensitive period of weeds. For weeds that are propagated by seeds, buds and seedlings are more sensitive to herbicides, so this period is often a suitable period for herbicide use. It is generally better to control the seedlings before or after weeding. When broad-spectrum herbicides are used, such as Gramoxone, Glyphosate and Roundup, etc., they should be used when the weeds are vigorously growing and have a significant herbicidal effect and a long duration. If we control weeds in spring and summer farmland, we should spray herbicides at the early stage of weed growth. Sixth, it is a pest-free period. From the perspective of effective control of squirrels, the release of scorpion should be better in the fasting stage of rats. Years of experiments have proved that the best effect of spring rodent control is due to the exhaustion of winter rattling food for rats and more corresponding to the feeding of toadstools; at the same time, spring rodent control can also reduce the number of bases to protect the normal emergence and safe growth of spring planting crops. . Seventh is the period of plant security. The safety of the agent to the plant is a prerequisite for determining the appropriate period of application. When pesticides are applied, the crops should be sprayed during periods when the crops have strong resistance to pesticides, so as not to cause crop injury. Eight is the safety interval. During the application period of pesticides, pesticides shall also be applied within the safety interval according to the standards for the safe use of pesticides so as to avoid excessive pesticide residues and adverse consequences.