Which pesticides are effective for controlling powdery mildew?

Powdery mildew is a common disease of many vegetables and melons, but beginner growers may not know how to deal with it. Today let us take a look at which pesticides to use for powdery mildew!

1. Which pesticides to use for powdery mildew

When powdery mildew appears on plants, you need to figure out the specific cause, and then you can choose some sprays or wettable powders to use. For different plants, the specific pesticides are also different.

2. Introduction to the agents

(1) During the overwintering period, spray or brush the branches and trunks with a diluted lime sulfur mixture at 3 to 5 degrees Baume. Note that flowers prone to pesticide damage, such as cineraria, must not be treated with it. Spray sulfur powder on the ground, generally using 25 grams to 30 grams per 70 sq m, to eliminate the overwintering source of the fungus.

(2) During the growing period, protective agents can be sprayed before the disease occurs, and systemic agents are suitable after the disease occurs. According to the symptoms of the disease, the growth of the flowers and trees, the climate conditions and the characteristics of the pesticide, apply the pesticide once every 5 to 20 days, for 2 to 5 consecutive applications. For flowers and trees in one season, one systemic agent can only be applied 1 to 2 times. The types of pesticides should be changed frequently to avoid the fungus developing resistance.

(3) When the disease is at its peak, you can spray 20% tetrafluoro.pyrazolate, 15% triadimefon 1000-fold solution, 2% kasugamycin aqueous solution 200-fold solution, 10% polyoxin 1000 to 1500-fold solution. Traditional drugs, due to repeated use, cause the fungus to develop antibodies and their effectiveness drops sharply, so alternating use is recommended. In addition, 1000-fold solution of baijiu (alcohol content 35%) can also be used, sprayed once every 3 to 6 days, for 3 to 6 consecutive sprays, washing the leaves until there is no powdery mildew.

(4) For flowers and trees grown in protected areas such as greenhouses and conservatories, in addition to spraying the various agents above, smoke agents and dust agents can also be applied. Before planting or after finishing, empty greenhouse disinfection should be carried out: use 250 grams of sulfur powder and 500 grams of sawdust per 100 sq m, mix evenly, divide into 10 piles, light them with red-hot coal briquettes or charcoal, do not use open flame, and keep the greenhouse closed for one day and night. During the fumigation process, strictly guard against fire. Fumigation during the growing period of flowers and trees is prone to cause pesticide damage, so it should be used with caution. During the plant growing period, use 45% chlorothalonil smoke agent before the disease occurs.

(5) Spraying 200-fold high-fat film (emulsion) has a good effect on preventing the occurrence of powdery mildew and treating early powdery mildew spots.