Timing and Precautions for Spraying Pesticides in Hot Summer Weather

Recently, many farmer friends have often asked us how to spray pesticides in hot weather so that crops are not harmed and the pesticide can fully exert its effect. Now we will explain in detail the points to note when spraying pesticides to control diseases, pests and weeds in hot summer weather:

1. Avoid spraying at noon during high temperature and strong light

Spraying chemical pesticides around noon, when the temperature is at its highest and the light is at its strongest, has two problems: first, the pesticide is highly volatile, which can easily cause poisoning of the applicator; second, most pests hide in cool, shaded places, so the spray is unlikely to hit the target, and at the same time the pesticide breaks down quickly and is lost heavily through volatilization, so the pest control effect is not ideal.

2. You can choose a rain-free cloudy day for spraying

If it is a sunny day, you should spray after sunrise between 8-10 am, or after 5 pm before sunset when there is no dew, when pests are most active. When the wind is strong, spraying should be stopped, otherwise the spray will be uneven and it can easily cause pesticide damage.

3. When spraying pesticides in summer, pay attention to personal protection and try to avoid contact between the pesticide and the skin.

4. Do not arbitrarily increase the concentration of the spray solution

Some farmers, in order to improve work efficiency or to enhance the control effect, often increase the amount of pesticide, reduce the dilution ratio of the pesticide, and arbitrarily increase the concentration of the spray solution, even in the hot summer season. Because water evaporates very quickly under the hot sun and high temperatures, if the concentration of the pesticide sprayed is too high, it can easily cause chemical damage to plant leaves.

5. Choose pesticides with fast action and strong systemic activity

Pesticides such as dichlorvos, fenpropathrin, procymidone and phoxim-cypermethrin emulsifiable concentrate have a strong toxic killing effect, and after use they destroy pests within 1-2 hours. Choose pesticides with strong systemic activity, such as dimethoate, methomyl and metalaxyl; after use, within 4-5 hours more than 80% of the active ingredient can be absorbed into the internal tissues of the crop, so that even if it rains, pests and pathogens can still be destroyed.

6. Add an adhesive to liquid and wettable powder pesticides

Pesticides have poor adhesion. When preparing the pesticide, add 100-150 grams of soybean flour or washing powder, or two bags of Jiamel Gold Drops, per 100 kg of spray solution as a synergist, which can improve the effectiveness of the pesticide.

7. Determine the safe interval before spraying according to the toxicity of the pesticide

Generally, the residual effect period of highly toxic pesticides is more than 1 month, and the residual effect period of low-toxicity pesticides is 7-10 days. Whether for grain, oil crops, melon crops or fruit trees, pesticide use should be stopped according to regulations before harvest to prevent poisoning of people and livestock.

Therefore, when applying pesticides in the hot summer season, even more attention should be paid to mixing enough water and ensuring the dilution ratio, with the spray solution dosage per mu being more than 45 kg. Avoid filling the tank too full; some farmers like to fill the sprayer tank very full when spraying. This is not only unfavorable for spraying, but more importantly, if the sprayer lid is not tightly sealed, the spray solution may splash onto the body while the applicator walks in the field, and in the hot season this can easily cause poisoning. The correct practice is that when mixing the pesticide, the upper liquid level in the tank should be below the scale line, and the sealing ring of the lid should be intact to ensure the lid is tightly sealed.

8. Reasonably mix and combine pesticides

When more than one disease occurs on a crop at the same time, pesticides can be mixed and used. For example, on cucumbers grown in protected cultivation, whiteflies or aphids and downy mildew, gray mold, etc. often occur at the same time, so usually the pesticide for controlling whiteflies or aphids (imidacloprid) is mixed with the pesticide for controlling downy mildew (metalaxyl-M + mancozeb) or the pesticide for controlling gray mold (iprodione, boscalid, fludioxonil, etc.).

The following points should be noted when mixing pesticides:

(1) The mixed pesticides must not undergo chemical changes;

(2) The mixed pesticides must not increase toxicity;

(3) The physical properties of the mixed pesticides should remain unchanged;

(4) The mixed pesticides should have different mechanisms of action or different control targets.

A friendly reminder: pesticide mixing should be done with caution, especially for some strongly acidic and strongly alkaline pesticides, so as not to reduce the pesticide effect and cause pesticide damage. Therefore, before using pesticides, read the label in detail, and test on a small area before using on a large area.