Persimmon anthrax

Persimmon anthracnose is one of the most destructive diseases affecting persimmon trees, particularly in recent years. Many growers have suffered significant losses due to this disease, with some even facing total crop failure. The disease causes severe defoliation, fruit drop, dieback of new shoots, and in extreme cases, the death of entire plants. **Symptoms** The disease primarily affects the shoots and fruits, though it can also infect leaves. Infected fruits initially develop small, dark brown to black spots on their surface. These spots gradually expand into round or oval lesions that are slightly sunken. The outer layer turns yellow-brown, and the diameter of the lesions ranges from 5 to 25 micrometers. The center of the lesion becomes dense, grayish-black, and resembles a vermiculite-like texture. Under humid conditions or after rain, pinkish, viscous material may ooze from the lesions. The infection often penetrates deeper into the fruit's cortex, forming black nodules. Typically, each infected fruit has one or two lesions, but many lesions may fall off early. Infected leaves show symptoms starting at the petioles and veins. They turn yellowish-brown and later become dark brown to black, appearing elongated or irregular in shape. New infections usually appear between late May and late June. Initially, small black circular spots appear on the surface, which then turn dark brown. The lesions grow larger and become oblong, with a slightly sunken center. The brown areas may split lengthwise, producing black dots—these are the conidial discs of the pathogen. During wet weather, red spore masses appear on the black spots. Lesions can be up to 10–20 mm long. The xylem beneath the lesions decays easily, and the tissue breaks apart. If the lesions on the branches are large, the parts of the branch above them may die. Fruit infection typically begins in late June and continues until harvest. **Pathogen** The causal agent is *Gloeosporium kaki* Hori, also known as *Colletotrichum gloeosporioides* Penz. It belongs to the subphylum Ascomycota and is a fungal pathogen. **Transmission and Disease Conditions** The fungus overwinters in infected branches, fallen fruits, leaf scars, and winter buds. Spores are produced in late summer and spread through wind, rain, insects, and direct contact via wounds. The incubation period for mycelium invasion is 3–6 days, while direct infection takes 6–10 days. High temperatures and humidity favor disease development. Heavy rains or sudden temperature increases after rainfall can trigger outbreaks. Varieties like 'Rich' and 'Yokono' are particularly susceptible. **Prevention Methods** 1. Improve cultivation practices, especially proper fertilization and irrigation, to avoid excessive vegetative growth. 2. Remove initial sources of infection by pruning diseased branches and fruits during winter, and thoroughly clearing fallen fruits, burning or burying them deeply. 3. Plant disease-free seedlings. Inspect all introduced seedlings carefully and remove any that show signs of infection. Soak healthy seedlings in a 1:3:80 Bordeaux mixture or 20% lime milk for 10 minutes before planting. 4. Apply protective sprays: Before the growing season, spray 5 times diluted lime sulfur or 45% crystalline lime sulfur at 30 times dilution. In June, mid-June, mid-July, and mid-August, apply a 1:5:400 Bordeaux mixture. Alternatively, use 1:3:300 Bordeaux fluid or 70% mancozeb wettable powder diluted 400–500 times, 50% benomyl wettable powder at 1500 times, or 70% thiophanate-methyl wettable powder at 1000 times. You can also use 100 grams of high-quality disinfectant per liter of water.

Water Cooling Chiller

Guangzhou Fuerle Health Technology Co., Ltd , https://www.fuerlegroup.com