What is the cause of watermelon Fusarium wilt? What are the harmful symptoms? A detailed explanation of comprehensive prevention and control methods is attached!

Watermelon Fusarium wilt, commonly known as "dead seedling disease", can occur in all periods, with the most serious disease in the fruit period, high soil water content and high humidity, so what is the cause of watermelon Fusarium wilt? What are the harmful symptoms? A detailed explanation of comprehensive prevention and control methods is attached!

I. etiology

Watermelon Fusarium wilt is caused by the infection of Fusarium oxysporum and Fusarium oxysporum. The pathogen overwinters in soil and in unripe fertiliser, and can survive for 5-6 years without the host, and some of the bacteria can survive for more than 10 years. The pathogen invades mainly through the root wound or the intercellular space at the tip of the root hair, first grows between and within the parietal cells of the host tube, and then enters the vascular bundle and develops in the duct. Bacteria secrete Pectinase and cellulase, decompose and destroy cells, accumulate pectins in ducts, block ducts, affect water transport, cause plant wilting, spread by bacteria-containing soil, continuous cropping, and there are many bacteria in the soil. the rate of diseased plants can reach about 70%, and seeds can also transmit disease.

Second, harmful symptoms

The seedlings were withered when the disease occurred. After the watermelon seedlings were planted, the lower leaves withered, then all the leaves of the whole plant withered, the base of the stem constricted, brown disease spots appeared, and sometimes amber glue flowed from the diseased part. there are white mildew layer and reddish slime (conidia) on it, vascular bundle browning of the stem, sometimes longitudinal cracks, root browning, rot with the stem.

III. Comprehensive prevention and control

The most effective way to control watermelon Fusarium wilt is grafting and changing roots. watermelon varieties are grafted with cucurbitaceae crops with high resistance to Fusarium wilt, such as gourd or Xintuzuo, as long as attention is paid to completely cutting off watermelon roots and not making the grafting interface contact with soil when seedlings are planted. It will effectively prevent the occurrence of watermelon Fusarium wilt.

Planting disease-resistant watermelon varieties is the first choice, such as Xinong No. 8 and Fengkang No. 8; watermelon Fusarium wilt pathogen is difficult to infect gourd, bottle gourd, pumpkin and so on. Grafting and changing roots with these crops as rootstocks is a better way to solve watermelon Fusarium wilt. Watermelon Fusarium wilt can survive in soil for 10 years, but only more than 130 days in water, so flood-drought rotation is the best way to prevent Fusarium wilt. Before sowing, soak it in bleach 2: 4% solution for 30 minutes and then remove it and clean it, which can kill Fusarium wilt and anthracnose on the seed surface; the nutrient soil for raising seedlings should be pond soil, paddy field soil or wall soil, forbidden melon field or vegetable garden soil, farm manure should be fully mature, and farm manure with diseased plant remains should not be used.

The above is the introduction of the causes and control methods of watermelon Fusarium wilt by the soil flow net. for self-rooted watermelons without grafting, we should adhere to the plant protection policy of "giving priority to prevention and comprehensive control" and conscientiously do a good job of agricultural control, biological control and other comprehensive control measures.