Points for attention in the use of fungicides

1. Use concentration: when spraying with liquid, it is often necessary to mix or dilute the agent into an appropriate concentration with water. Too high concentration will cause drug damage and waste, while too low concentration will be ineffective. Some non-wettable or difficult to wetting powder, you should first add a little, the powder into a paste, and then add water to prepare, you can also add some wetting agents.

2. Spraying time: spraying time too early will cause waste or reduce the control effect, but if it is too late, a large number of pathogens have invaded the host, and even if the therapeutic agent is sprayed, there will be little harvest. Spraying should be protected in time according to the law of the disease and the situation at that time or according to the short-term prediction.

3. Spraying times: the spraying times are mainly determined according to the residual period of the medicine and meteorological conditions. Generally, it is sprayed once every 10 murals and 15 days, and a total of 3 times are sprayed. Supplementary spraying after rain should consider the cost and save the use of medicine.

4. Spraying quality: if the amount of spraying is appropriate, all parts of the plant cannot be carefully protected if there is too little, and if there is too much, it will be wasted or even cause drug damage. Spraying requires fine fog and uniform spraying, and all parts that should be protected by the plant, including the front and back of the leaves, should be sprayed.

5. The problem of drug damage: there are many reasons for the drug damage to plants caused by spraying. The agents with strong water solubility are easy to cause drug damage, and different crops have different sensitivity to drugs. For example, Bordeaux liquid generally does not cause drug damage, but crops that are sensitive to copper can also cause drug damage. Beans, potatoes and cotton are sensitive to stone sulfur mixture. Different developmental classes of crops have different responses to insecticides, and it is easy to cause drug damage at the flowering stage of seedlings and booting. In addition, it is also related to meteorological conditions, generally, the effects of temperature and sunshine are more obvious, high temperature, strong sunshine or heavy fog, high humidity are easy to cause drug damage.

6. How to mix: pesticides that are easy to decompose and fail with alkaline substances can not be mixed with alkaline substances. For example, alkaline fungicides such as Bordeaux solution and stone-sulfur mixture cannot be mixed with 1605, dimethoate, dichlorvos, etc. Chemical reactions after mixing can not be mixed with agents that can cause drug damage. A small number of pesticides have a synergistic effect after mixing. For example, the mixed use of dimethoate neutral and acidic bactericides such as dimethoate zinc, wettable sulfur and colloidal sulfur is not only unaffected, but slightly improved.

7. Drug resistance: long-term use of single agents (mainly internal inhalation fungicides) will lead to drug resistance of pathogens and invalidate the agents used. In order to avoid this problem, different types of agents can be used alternately, or a mixture of internal fungicides and traditional fungicides can be used.