Prevention of guava root knot nematode disease
In recent years, Daxing, Tongzhou and other places have successively carried out the construction of Nanguo North Plantation, and they have introduced a large number of Taiwan guava, but they all suffered from root-knot nematodes in varying degrees. Phytosanitary station technicians in the Daqing District Changli Jinyuan (Beijing) Tropical Botanical Garden conducted a survey of pests and found that root knot nematode disease in the park is very serious. Damage symptoms Root-knot nematode disease rarely shows symptoms at the seedling stage, mainly after six months of planting. Severely diseased fruit seedlings with pale yellow leaves, sparse leaves, slow growth, severe dwarfs of severely diseased plants, yellow drooping leaves, and purple leaves of whole plants at low temperatures in winter; many root nodules are formed in the roots of the diseased plants, the epidermis is brown, and the main roots are swollen After rot, the whole root system rots and loses its vitality. The aboveground parts will immediately die. When the temperature is high, the symptoms are most obvious. The condition is more serious in drought. The law of incidence The pathogenic nematodes overwinter as eggs and females. When the external conditions are suitable, the eggs develop into first-instar larvae in the oocysts, which break out of the eggs after being molted, become second-instar larvae, move in the soil, invade young roots, and damage between the root bark and the middle column. Irritated tissue forms irregular nodules. The primary infestation source was nematode fruit seedlings, which were disseminated by insects in the form of farming personnel, agricultural implements, and irrigation water. Control methods Root-knot nematode disease is a soil-borne disease with great difficulty in prevention and control. In prevention and control, the principle of "prevention-oriented, comprehensive prevention and control" should be adhered to. Strengthen plant quarantine. In order to protect the disease-free zone and the new zone, the introduction of diseased seedlings must be strictly prohibited. Remove the diseased body in time. When a diseased plant in the orchard is found, the orchard must be cleared thoroughly and promptly and burned. The planting holes were dug for one month and disinfected with lime before they could be replanted. Agricultural control. One is to apply more organic fertilizer to improve resistance; the other is to use small water in the dry season to keep the roots moist and promote plant growth; third is to increase potash fertilizer and enhance plant resistance. Physical control. The long-term moist in the orchard can make the nematode suffocate and suffocate, which can effectively inhibit the infection and reproduction of nematodes. In the summer hot season, using plastic film to tile the ground and compaction, the soil can reach a temperature of 30°C-40°C in a depth of 10 cm for 3-5 days, effectively killing a large number of nematodes in different insect states. Chemical control. Pay attention to the selection of low toxicity, low residue pesticides. Seedling treatment. Before the transplanting, the seedlings were sterilized and killed to kill some pests and germs. The omethoate 1000 times solution was mixed with a broad-spectrum fungicide and the roots were immersed for 30 minutes. For the more obvious symptoms, the dipping time should be extended. Soil treatment. The planting shed uses Weibaimu or horseradish and other soil disinfectants to disinfect the soil; before planting, 250g of lime powder is applied at the side of the planting hole, and each plant is applied with 3 to 40% of the 25-gram Merrill granules. In the guava root system, it is ensured that the extracted new root is no longer infected with root-knot nematodes. YT-H706 YT-H706 Shenzhen Sunshine Technology Co.,Ltd , https://www.yatwinsz.com