How to treat powdery mildew effectively? A detailed guide to prevention and control methods

Powdery mildew is a common plant disease that mainly damages leaves, and also damages stems and ears. The main crops it harms are wheat, cucumber, grapes and so on. So, how is powdery mildew treated?

1. How is powdery mildew treated?

When buying seedlings, choose disease-resistant varieties to eliminate the source of the disease. If infection has already occurred, in the early stage of the disease spray the leaf surface with 27% high-lipid film at 100 times dilution, once every 6 to 7 days, for 3 to 4 consecutive sprays; when the disease is in full outbreak, you can spray 20% tetrafluoropyrazole ester, 15% triadimefon at 1000 times dilution, 2% anti-mildew fungicide aqueous solution at 200 times dilution, or 10% polyoxin at 1000 to 1500 times dilution until there is no powdery mildew left. Traditional pesticides, because of repeated use, cause the pathogen to develop antibodies and their effectiveness drops sharply, so alternating use is recommended.

2. The harm caused by powdery mildew

In the early stage of the disease, the spots are white, and then the color gradually turns light brown, and black cleistothecia can form through selfing or hybridization. Under normal circumstances, there are more spots on the lower leaves than on the upper leaves, and more on the underside of the leaves than on the upper side. In the early stage, the mold spots are separate and scattered, and later they merge into one large mold spot that can even cover the entire leaf, seriously affecting photosynthesis, disrupting normal metabolism, causing premature aging and loss of yield.

There are two main conditions for powdery mildew to become epidemic: one is large-scale planting of susceptible varieties, and the other is suitable environmental conditions. Generally, when wheat is planted too densely and nitrogen fertilizer is applied excessively, the wheat plants grow excessively and the plants become weak; in wheat fields with high humidity or where lodging has occurred, the disease tends to be more severe. The disease generally shows disease centers from the end of March to the beginning of April, and after mid-April, as temperatures gradually rise, the rate of diseased plants increases rapidly, leading to a major epidemic under suitable conditions.

The treatment of powdery mildew is mainly about eradicating it at the source. If it has already broken out, chemical treatment needs to be adopted. I hope the above content can be helpful to everyone.