Control Methods and Technical Key Points for Mango Powdery Mildew

Mango is prone to powdery mildew during the flowering stage, young fruit stage and tender leaf stage. If not controlled in time, it will cause massive fruit drop and reduce yield.

Mango powdery mildew is a fungal disease that mainly affects inflorescences, young fruits and tender leaves. On affected organs, scattered small white moldy patches first appear, which later form a layer of pale white moldy powder. Flowers and sepals are most susceptible, while petals are relatively resistant. After flowers and flower stalks are infected, they stop growing and cannot bloom, then drop off after 2 to 3 days; on young fruits, the moldy powder layer often covers the entire fruit surface, and affected fruits usually drop off when they grow to the size of a finger; lightly affected fruits may continue to grow, sometimes with the affected epidermis cracking to form cork tissue; after mature fruits are infected, irregular patches appear. It is prone to becoming epidemic at temperatures around 20C to 25C.

Cultivation control

1. Select disease-resistant varieties.

2. Strengthen management during cultivation.

3. Thoroughly clean the orchard after harvest and before flowering, and maintain good orchard sanitation.

Chemical control

Sulfur agents such as lime sulfur mixture and colloidal sulfur, especially fine sulfur powder, have a special effect on controlling this disease. During the new shoot stage, lime sulfur mixture can be sprayed (0.4 to 0.5 Baume degrees in spring and autumn, 0.8 Baume degrees in winter, and 0.2 to 0.3 Baume degrees in summer; the spray volume for a grown tree is about 5 to 7.5 kg per plant). Sulfur powder and wettable colloidal sulfur can also be sprayed, but the cost is relatively high. During the flowering stage, sulfur powder or wettable colloidal sulfur (diluted 150 times with water) should be sprayed, with the first application before and after flowering, and the second application when the petals fall and small fruits form. Sulfur powder particles should be fine, with passing through 300 to 325 mesh as the standard; if the particles are too large, the control effect decreases. Spraying should be done in the morning when the dew has not yet dried.

In addition, the following agents can also be tried for control: (1) 50% thiophanate-methyl wettable powder at 1500 times dilution or carbendazim at 1500 times dilution; (2) 50% zineb wettable powder at 500 times dilution; (3) 50% amobam aqueous solution at 1000 times dilution; (4) 75% chlorothalonil wettable powder at 500 to 800 times dilution; (5) 50% tecloftalam wettable powder at 800 to 1000 times dilution by spraying.