Control of Brown spot of Pomegranate

Distribution and harm: it occurs in pomegranate producing areas in China. It mainly harms leaves and fruits, causes early fruit drop and leaf drop, and causes varying degrees of loss to pomegranate production.

The main results are as follows: 1. After the injury of the leaves in symptom recognition, small black and brown spots appear at the initial stage, and then enlarge as near-circular spots, and the disease spots gradually expand, which are often square or polygonal spots due to the limitation of the main and lateral veins, and in severe cases, multiple disease spots are connected into irregular spots. The edge of the lesion is black to dark brown, slightly convex, and the central color is slightly light. The symptoms on both sides of the leaf are the same, and the gray-black mildew layer is produced on the disease spot, that is, the conidiophores and conidiophores of pathogenic fungi.

The disease spot on the fruit is nearly round or irregular, dark brown slightly sunken, and there is also a gray-black mildew layer on it.

Second, the pathogen overwintered on the fallen leaves and formed conidia in April of the following year for primary infection. Again infect the conidia produced on the newly diseased leaves. It usually occurs from May to June, and the peak period is from July to August. Warm and rainy years are beneficial to the occurrence of diseases. The orchard is seriously ill due to poor management.

III. Prevention and control measures

1. Strengthen cultivation management and reasonable pruning, improve ventilation and light transmission conditions among fruit trees, and rational application of fertilizer and water, so as to enhance tree potential and improve disease resistance. Timely removal of diseased bodies buried or burned in order to reduce the pathogen overwintering place and put an end to the source of primary infection.

two。 1 ∶ 1 ∶ Bordeaux solution was used in the initial stage of the disease. After 14 days, the following pesticides were used: 50% carbendazim 600 times 800 times, or 77% 500 times 800 times, or 80% carbendazim 800 times, or 40% carbendan 600 times, or 50% carbendan 600 times. One of the above chemicals can be sprayed once every 10 days, and it can be sprayed for 2 times in a row.