Powdery Mildew Causes Leaf Browning and Death How to Control Powdery Mildew of Cucurbita

Powdery mildew of zucchini is mainly harmful to leaves, followed by petiole and stem, and less to zucchini fruit. At the initial stage of the disease, white powdery small round spots were produced, and then gradually expanded into irregular white powdery mildew spots (that is, conidia of pathogens). The diseased spots can be connected into pieces, and some of the damaged leaves gradually turn yellow. in the later stage, many small yellowish-brown particles were produced on the disease spot (that is, the ascomycetes of the bacteria). When it is serious, the diseased leaves turn brown and die.

Powdery mildew of zucchini

The cause of the disease: the pathogen of powdery mildew overwintered with the remains of cucurbit disease in the soil or in the protected area. The pathogens in the southern vegetable area overwintered and oversummer with hyphae or conidia on the host. Spread by airflow, Rain Water and watering. 10 Mel 25 ℃ could cause the disease, and the disease developed rapidly due to the alternation of high temperature, dryness and humidity. In the later stage of growth, the disease of zucchini plant growth was serious. The disease is also serious because of overdense planting and lack of fertilizer during the growing period.

Integrated prevention and control technology:

(1) clean the countryside and remove the residual plants. The old and diseased leaves of the diseased plant should be removed as soon as possible, and the diseased plant should be cleared out of the field or burned.

(2) strengthen field management. Reasonable ventilation and light transmission, fertilization and watering. Prevent plant from overgrowth and drought senescence, and plant growth is robust.

(3) biological chemical control. Nongkang 120 was sprayed with water at the initial stage of the disease, once every 7 days and continuously for 2 times.

(4) smoke control. In the early stage of the disease, 45% chlorothalonil smoke remover (safe type) can be used in the protected area, the dosage of 110g~180g per mu is divided into 4 and 5 places, and the shed is lit and fumigated overnight, usually once every 7 days, even 3 times for 4 times.

(5) spraying prevention and treatment. At the initial stage of the disease, 2500-3000 times of 25% triadimefon wettable powder, 2000-2500 times of 30% Teflin wettable powder, 2000 times of 25% triadimefon EC, or 2 000 times of 10% high water dispersible granules, or 40% polysulfide suspension can be used to spray zucchini leaves at the initial stage of the disease, spray zucchini leaves once every 14 days for 3 times.