How to prevent and control pomegranate brown spot? A detailed guide to practical methods
Distribution and harm: It occurs in all pomegranate-producing areas in China. It mainly harms leaves and fruits, causing early fruit drop and leaf drop, and causing varying degrees of loss to pomegranate production.
I. Symptom identification After leaves are infected, small dark brown spots appear at first, then expand into nearly round spots. The lesions gradually enlarge and are often restricted by the main and lateral veins, forming square or polygonal spots. In severe cases, multiple lesions connect to form irregular large spots. The edges of the lesions are black to dark brown, slightly raised, and the center is slightly lighter in color. The symptoms on the front and back of the leaves are the same, and a gray-black mold layer forms on the lesions, which is the conidiophores and conidia of the pathogenic fungus.
On the fruit, the lesions are nearly round or irregular, dark brown and slightly sunken, and also bear a gray-black mold layer.
II. Occurrence pattern The pathogen overwinters on fallen leaves, and in April of the following year forms conidia for primary infection. Reinfection comes from conidia produced on newly diseased leaves. It generally occurs commonly from May to June, and July to August is the peak period of the disease. Warm and rainy years are favorable for the occurrence of the disease. Orchards with poor management have severe disease.
III. Control measures
1. Strengthen cultivation management Carry out reasonable pruning, improve ventilation and light conditions between fruit trees, and apply fertilizer and water reasonably to enhance tree vigor and improve disease resistance. Remove diseased residues in time and bury them deeply or burn them in a centralized manner to reduce overwintering sites of the pathogen and eliminate the source of primary infection.
2. Chemical control At the early stage of the disease, use 1:1:140 Bordeaux mixture. After 14 days, use the following pesticides: 50% carbendazim 600-800 times liquid, or 77% copper hydroxide 500-800 times liquid, or 80% captafol wettable powder 800-1000 times liquid, or 40% folpet wettable powder 500-600 times liquid, or 50% captan wettable powder 600-800 times liquid. Choose any one of the above pesticides and spray once every 7-10 days, for 2-3 consecutive sprays.