Control of powdery mildew of Hami melon

Powdery mildew is the main disease of Hami melon, which is widely distributed and occurs in protected and open fields, which seriously affects the yield and quality of Hami melon.

Symptoms can occur throughout the growth period and can infect leaves, petioles and stem vines. At the initial stage, a small white powder spot was formed on the leaf surface, and many disease spots converged into large irregular spots, and then the leaf surface was covered with white powder, that is, pathogen conidiophores and conidia. With the development of the disease, the diseased leaves gradually aged and died, and sometimes there were black spots on the necrotic spots, namely the ascomycetes. The petiole and stem vine are infected with disease, and white powdery mildew spots are also produced on the surface. In severe cases, the disease spots are densely spread, the tissue is senescent prematurely and die.

Pathogen Sphaerothecafuliginea (Schl.) Poll. It is called monofilament powdery mildew, which belongs to ascomycete subphylum fungi. The conidiophores of the pathogen are cylindrical, colorless, unbranched, apical conidia. Conidia unicellular, colorless, oval, 18.4-36.8 μ m × 14.5-20.1 μ m. The closure shell is rarely produced in the sexual stage.

The pathogen overwintered with the disease remains in the protected area, and the conidia could also survive the winter on other hosts and spread by airflow and Rain Water. Bacteria like temperature and humidity, drought tolerance, high temperature drying and humidity alternately conducive to the occurrence and development of the disease. The growth temperature of the pathogen is 10-30 ℃, the suitable temperature is 20-25 ℃, the relative humidity is 25%-85% conidia can germinate, and the disease is suitable for high humidity conditions. In the middle and later stage of growth, the plant growth was weak and the disease was serious.

Prevention and cure method

(1) breeding and planting disease-resistant varieties according to local conditions.

(2) strengthen cultivation management.

Adopt high border planting, reasonable close planting, pay attention to ventilation and ventilation; scientific fertilization, apply sufficient base fertilizer and increase phosphorus and potassium fertilizer during planting, avoid late de-fertilization and cultivate strong seedlings; timely irrigation, pay attention to the combination of drainage and irrigation to prevent excessive humidity in the field; pruning and forking in time, diseased plants are pulled out in time.

(3) Pesticide control.

The use of sulfur fumigator for regular fumigation prevention is advocated in protected areas.

At the initial stage of the disease, choose 2% agricultural antibiotic 120 water agent, or 2% Wuyisin water agent 200,300x, or 43% butyrate suspension 8000 times, or 10% Shigao water dispersible granules 8000 times, or 40% Fuling EC 8000 times, or 25% Bailitong wettable powder 2500 times, or 30% Teflin wettable powder 4000 times, or 25% Fenning wettable powder 1000-1500 times spray. At the initial stage of planting disease in protected areas, choose 5% chlorothalonil dust agent or 5% plus Renong dust agent, or 15kg/hm2 dust spray of the above spray agents, the control effect is ideal.

Commonly used agents are agricultural antibiotic 120, Wuyisin, Shilike, Shigao, Fuxing, Bailitong, Teflin, Phenrust Ning, Chlorothalonil, Carinon.