A, white powder should be powdery mildew, treatment is recommended ethermethrin or etofenprox or etofenprox sulfonate or oximethrin to choose one, alternate use. These products are safe and effective, the cost is higher, the prevention can reduce the dosage. Spray to hit all over and penetrate. (Tetrafluoroetherazole, chitosan, rhododendron methyl ether and other ingredients are quite safe, but the therapeutic effect is general, it is recommended that the early prevention of the use of treatment or treatment mixed with the above therapeutic products used)

You can also use triazole pesticides such as procyclazole or flusilazole or fusidicarb or fusidicarb or tebuconazole or hexaconazole and so on, the cost of these products is low, but pay attention to the dosage or the number of times the cumulative will inhibit growth. More often accumulated will inhibit growth or burn flowers or deformed fruit or leaf hardening (not recommended after flowering and fruiting).

Tips? Benzothiazole, pyrimethanil is not effective in the treatment of powdery mildew, prevention can be.

If it is a greenhouse to control humidity, rainy days using fumigants to control the development of the disease.

Be sure to use thirteen morpholine, aliconazole, fluconazole, triadimefon powder rust Ning and other powerful triazole pesticides, as well as sulfur, polysulfuric acid suspension, lithosulfuric acid composite and other components, the side effects of quite large. The loss is not worth the gain, remember!

Prevention-oriented, integrated control. Alternate pesticide components, do not continuously use the same pesticide components. This is the principle of plant protection.

Second, the other symptoms suggest taking a clear picture of the reverse side of the photo to see it!