Plant verticillium wilt is a serious vascular disease, and its pathogens are mainlyverticillium dahliae (Verticillium dahliae Kleb) and Verticillium alboatrumSeminaria, Aleurosporaceae, Verticillium.
The suitable growth temperature of Verticillium black-and-white was lower than that of Verticillium dahliae.There are many reports on solanaceous plants and Shouji plants;However, due to its wide range of hosts and strong adaptability to high temperature and severe temperature changes, Verticillium dahliae is mainly reported on many plants infected with verticillium wilt, such as cotton.
Open field cultivationFrom about one month after planting, diseases appeared on the ground and continued to occur at the end of harvest.At first, the lower leaves wilted locally and the leaf edges rolled up.After 2-3 days, the diseased part turns from yellowish white to yellow.The leaf edge has more discoloration, and is wedge-shaped with the small leaf vein as the center.Next, the discolored part gradually expands, the whole leaflet turns yellow, and slowly turns brown and withers.When the disease worsens, the upper leaves will also die in turn, and the lower leaves will be chronically withered.Therefore, the height of diseased plants decreased, fruit setting and growth of fruits were significantly affected.The petiole of the diseased plant was intact by autopsy, and yellow browning was seen in the duct.
pathogeny
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In Japan, in addition to tomatoes, there are also infected eggplant, green pepper and white melon.Melon, Caoshi, okra, cabbage, radish, bee dipper, Chinese angelica, spiny sprouts, soybean, chrysanthemum, rose, etc., have a wide range of hosts.The pathogen has different systems of pathogenicity to tomato, and is divided into three pathogenic types. In addition to mycelium, it also formsConidiaAnd sclerotia.Sclerotium is a persistent organ generated by the spore division of hyphae, which is generated in large quantities on diseased plants and overwinters in soil in the form of sclerotium.These sclerotiums, together with the diseased strain residues, spread to the surrounding areas through wind and rain.In addition, infected seedlings can also bring the pathogen to non diseased areas.After the seedlings are transplanted, the sclerotia sprouts and sprouts out of the tube and grows mycelium, which infects the plants from the top of the root and the wound.The pathogen invading the plant mainly propagates in the duct, hinders the rise of water and produces toxin, leading to plant wilting.
Plant protection management
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The optimum temperature for the disease is about 25 ℃. When the temperature reaches 22~28 ℃, it is easy to get sick, but it is difficult to get sick at low temperature below 20 ℃ and high temperature above 30 ℃.Therefore, tomato cultivation in summer and autumn in mountainous areas and open field cultivation on flat land are more prone to diseases.The incidence of disease was higher in tomato continuous cropping fields and fields with high rotation frequency of eggplant, strawberry and Chinese angelica.When the disease is caused by incomplete disinfection on the bed, the damage is especially serious.Many resistant varieties are sold.At the same time, attention should be paid to avoiding continuous cropping of tomatoes or rotation of eggplant, and timely disinfecting the bed soil.The soil or resistant varieties should be disinfected in the plot with high incidence of disease.
1、 Eradicate sporadic disease areas, control light disease areas, and transform serious disease areas
verticillium wilt
2、 Seed disinfection treatment
3、 Health care cultivation.Reduce phoxim, methamidophos, etcOrganophosphorus pesticideThe frequency and concentration of drug application can prevent cotton plants from being damaged by drugs and reduce their disease resistance.Do not apply nitrogen fertilizer on a partial or excessive basis. Do a good job of combining nitrogen, phosphorus and potassium. Pay attention to increasing potassium fertilizer to improve disease resistance.Improve the ecological environment of the cotton field to make the soil temperature in the cotton field higher, but the humidity should not be too high. Avoid flooding, which can reduce the incidence of disease.
