How to prevent and control anthracnose in peach trees? These methods are very practical
Along with the adjustment of the agricultural industrial structure, the planting area of peach trees in our county has continued to expand. Due to the influence of various factors such as climatic conditions, varieties, and management, peach anthracnose occurs rather severely and has a relatively large impact on peach yield and quality. Effective prevention and control of anthracnose is very important for increasing yield and benefits.
1. Damage symptoms. The disease mainly damages fruits, and can also infect leaves and new shoots. When young fruits are affected, they initially show light brown water-soaked spots, which later, as the fruit expands, become round or oval, reddish brown, with a sunken center; when the climate is humid, orange-red small granular dots grow on the diseased area. After young fruits are infected, they stop growing, forming early fruit drop; when the climate is dry, mummified fruits form. The lesions on mature fruits show obvious concentric ring-like shriveling. Leaf lesions are round or irregular and light brown. The boundary between diseased and healthy tissue is obvious; later the lesions become grayish brown, dry up and fall off, causing shot holes. Lesions on new shoots are long oval, dark brown, and slightly sunken. Leaves on diseased shoots curl upward, and in severe cases the shoot tips often die.
2. Pathogen and disease occurrence pattern. Peach anthracnose is a fungus of the genus Colletotrichum in the phylum Deuteromycota. The pathogen overwinters as mycelium in diseased branches and diseased fruits. In the following year, when suitable temperature and humidity conditions occur, that is, when the average temperature reaches 10-12°C and the relative humidity reaches above 80%, it begins to form spores, which spread through wind and rain and insects, forming the first infection. The disease has a long damage period and can infect throughout the entire growth period of peach. High humidity is the leading trigger for the occurrence and epidemic of this disease. Low temperature and frequent rain during the flowering and young fruit stages, and warm, cloudy, foggy, and humid conditions during the fruit ripening stage are favorable for disease development. Peach orchards with extensive management, heavy clay soil, poor drainage, excessive nitrogen application, and a closed canopy suffer severe disease.
3. Prevention and control techniques
1. Orchard planning: Never establish an orchard in low-lying, poorly drained clay soil areas. Transplant on raised ridges, and pay attention to variety selection.
2. Strengthen cultivation management: Apply more organic fertilizer and phosphorus and potassium fertilizers, carry out timely summer pruning, improve tree structure, and provide ventilation and light penetration. In combination with winter pruning, remove dead branches, mummified fruits on the trees, and fallen fruits on the ground, and burn them in a centralized manner or bury them deeply to reduce sources of infection.
3. Chemical control. Before budbreak, spray 3-4 degrees Beaume lime sulfur mixture plus 80% sodium pentachlorophenate 200-300 times solution, or 1:1:100 Bordeaux mixture, to eradicate the pathogen source. Spray once before flowering. After petal fall, spray once about every 10 days, for a total of 3-4 sprays. The agents can be 70% thiophanate-methyl wettable powder 1000 times solution, 80% anthracnose thiram wettable powder 800 times solution, 50% carbendazim wettable powder 600-800 times solution, 50% captan 400-500 times solution, or 50% dithianon wettable powder 1000 times solution. It is best to use the agents alternately.