Control methods of Fusarium wilt of watermelon

Watermelon Fusarium wilt, commonly known as dead seedling disease, can occur in all periods of watermelon, and the disease is the most serious in the fruiting period. the suitable temperature of the pathogen is 25: 30 ℃, and the incidence is mild when the soil temperature is lower than 23 ℃ and higher than 34 ℃. The disease is serious when the soil water content is high and humidity is high. Planting resistant watermelon varieties is the first choice to control the disease. Let's take a look at the control methods of watermelon Fusarium wilt.

Harmful symptoms

The seedlings showed a standing withered shape when they fell ill. After planting, the lower leaves withered, then all the leaves of the whole plant withered. The base of the stem is constricted with brown spots, and sometimes an amber gel flows out of the disease, on which there is a white mildew layer and a reddish slime (conidia). The vascular bundles of the stem turn brown, sometimes with longitudinal fissures. The root browned and rotted with the stem.

Etiology

The pathogen of Fusarium oxysporum of watermelon invaded mainly through the root wound or the intercellular space at the tip of root hairs. It first grew between and within the parietal cells of the host tube, then entered the vascular bundle, developed in the duct, secreted Pectinase and cellulase, decomposed and destroyed cells, accumulated pectins in the duct, blocked the catheter, affected water transport, and caused plant wilting. Rely on bacteria-containing soil transmission, continuous cropping, there are many germs in the soil, the rate of diseased plants can reach about 70%, diseased bodies and feces, seeds can also transmit disease.

Integrated prevention and cure

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. For self-rooted watermelons that are not grafted, we should adhere to the plant protection policy of "giving priority to prevention and comprehensive control", and conscientiously do a good job of comprehensive control measures such as agricultural control and biological control.

Agricultural prevention and control

1. Variety selection: planting disease-resistant watermelon varieties is the first choice, such as Xinong No. 8, Fengkang No. 8 and so on.

2. Grafting cultivation: watermelon Fusarium wilt pathogen is difficult to infect gourd, bottle gourd, pumpkin and so on. Using these crops as rootstocks to change roots is a better way to solve watermelon Fusarium wilt.

3. Flood-drought rotation: 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.

4. Seed treatment: soak it in bleach 2-4% solution for 30 minutes and then remove it and wash it clean. It can kill Fusarium wilt and anthracnose on the seed surface.

5. Soil control: pond soil, paddy field soil or wall soil should be selected for seedling cultivation, melon field or vegetable garden soil should be prohibited, farm manure should be fully mature, and farm manure with diseased plant residues should not be used.