Control of powdery mildew of Lycium barbarum

[symptom characteristics] mainly harms the leaves. The leaves are covered with white mildew spots (initial) and powder spots (later). This white mildew spot and powder spot are not only the symptoms of the disease, but also the symptoms of the disease (conidiophores and conidia). In severe cases, the plant of Chinese wolfberry appears white, which is quite eye-catching. The photosynthesis of diseased plants was blocked, which eventually caused the leaves to turn yellow and easy to fall off.

[pathogen and pathogenic characteristics] the pathogen is Oidiumsp. In cold areas, the pathogen overwintered in the soil with the disease residue as a sexual fruiting body. In warm areas, the pathogen mainly carried out the initial invasion and re-invasion by apomorphic conidia, and completed the annual cycle of the disease, and there was no obvious overwintering period. Warm and humid weather or planting environment is conducive to the disease. However, the spores of the pathogen have the characteristics of drought tolerance and can still sprout and infect and cause disease under the condition of high temperature and drought.

[prevention and control methods] early spraying should be used to prevent and control the disease. Like rust, powdery mildew is sensitive to triadimefon and to organic or inorganic sulfur fungicides. Before the onset of the disease, no later than after the onset of the disease, 45% lime-sulfur mixture crystallization or paste solution, or 50% colloidal sulfur or ultra-fine sulfur suspension 200 times 400 times, or 15% powder rather than wet powder 2000 times, or 70% mancozeb 600 times, 2 times 3 times, every 7 days or so (colloidal sulfur, stone sulfur mixture, ultra-fine sulfur suspension) or 10 days (mancozeb) to 20 days or more (trimethoprim) was sprayed alternately. Spray foot evenly to prevent and control the disease.