Flower rot is a bacterial disease, and the pathogen is Pseudomonas. It can be transmitted by rainwater, insects, and diseased residues, and invades through pores and wounds. It is prone to disease under high humidity and normal temperature, and mainly harms flowers and young fruits. Infected flower buds and sepals show brown sunken spots at the initial stage of symptoms, and the spots develop quickly. When the pathogen invades the inside of the buds, the petals turn orange, turn brown when they open, and begin to rot and fall off soon. Flowers that are not seriously damaged can also open, but the anthers and filaments turn brown or black and then rot. The dried petals hang on the young fruit and do not fall off. After the pathogen invades the ovary, it causes the young fruit to turn brown and shrink, and the diseased fruit is easy to fall off. Occasionally, it can develop into a small fruit, and it is often deformed. The fungus also harms the leaves. The symptoms are brown spots, which gradually expand, and eventually the whole leaf rots and withers and droops.
Prevention methods:
① Improve the ventilation and light transmission conditions of the flower buds;
② Spray 1% Bordeaux mixture 3 times after fruit picking and before germination, spray 100 mg/kg agricultural streptomycin from germination to flowering stage, or spray 5 Baume degrees lime sulfur mixture once before germination and flower bud stage at the end of March, or 20 % ferbam wettable powder 800 ~ 1000 times liquid. Orchards with severe disease should be sprayed with 500-600 times liquid of 5% bacterial toxin clear water agent in the middle and late May.
