Detailed Explanation of Common Watermelon Diseases and Control Methods
Watermelon is one of the fruits many people love to eat most, but the watermelon itself is very fragile. It is not only highly sensitive to the surrounding environment, but also encounters many diseases during its growth process, and a single slip may endanger an entire watermelon field. So what diseases harm watermelons? Below, the editor will explain several common diseases of watermelon.
1. Watermelon Phytophthora blight
Watermelon Phytophthora blight usually occurs in the high-temperature rainy season. Poor drainage in the watermelon field and planting too densely can both trigger it. It harms the roots and stems of watermelon, and in severe cases also affects the leaves, fruits and vines. When it develops at the root crown, dark green patches appear, and the patches develop around the stem, causing the stem to rot, and finally leading to the complete death of the whole plant. The symptoms on leaves, fruits and vines are similar. Before sowing, disease-resistant varieties can be selected, such as Qiongxue and others. Never rotate with melon and fruit vegetables after the watermelon field is harvested. Diseased melons should be removed promptly to prevent infection. When melons show disease, pesticides can be sprayed for control, such as cymoxanil mancozeb and others, sprayed once a week for about one month.
2. Watermelon leaf blight
Watermelon leaf blight is a relatively common disease of watermelon, with a higher incidence rate in spring and autumn, mainly due to more rainy weather. Leaf blight mainly harms the leaves, followed by the vines and fruits. It mostly occurs on young leaves, producing irregular brown patches on the young leaves, and continued growth causes the leaves to wither. When it occurs on fruits and vines, the fruits and vines rot. There are specialized disease-resistant varieties against leaf blight on the market, such as Zhengza No. 7 and others. After harvest, pay attention to cleaning up diseased melons and burn them in a centralized manner. Establish a good drainage system for the watermelon field, and pay attention to rain protection during rainy weather. Before lesions appear, procymidone wettable powder can be used for spraying control, also once a week, sprayed for about one month.
3. Watermelon Fusarium wilt
Fusarium wilt generally occurs at the fruiting stage. The seedlings stand upright in a wilted state, causing all the leaves to wither, and the vine roots rot and turn brown. This is mainly because the pathogen enters through wounds in the roots, grows inside the cells, and secretes substances such as pectinase that destroy the cells, causing the vessels to become blocked and unable to transport water and nutrients. The best way to control Fusarium wilt is to graft watermelon onto crops that are not susceptible to Fusarium wilt, such as bottle gourd and others. Disease-resistant varieties on the market include Xinong No. 8 and others. To prevent Fusarium wilt, aquatic crops can be rotated in the watermelon field, because the Fusarium wilt pathogen survives in water for only more than 100 days. Finally, choose soil rich in nutrients, and do not use fertilizer containing diseased residues.
4. Watermelon gray mold
Gray mold is caused by the invasion of Botrytis cinerea, and is especially severe in the rainy season in the south. It mainly harms leaves, fruits and stems. On the leaves it produces gray irregular patches, finally causing withering. Gray patches also appear on the fruit stems, making the fruit stems unable to grow normally and producing deformed fruits. Gray mold is the most serious disease of watermelon, and in the most severe cases it can cause all the watermelons in an entire field to become deformed and unsellable. Wuyi mycin aqueous solution and Fenmeibao wettable powder can be used for spraying, once a week, sprayed for about one month. Rotation should be at least more than 4 years, and abundant organic fertilizer should be used.
5. Watermelon powdery mildew
Powdery mildew mainly occurs more severely in autumn in the south. It mainly harms the leaves and generally has little effect on the fruits. Many small white particles are produced on the leaves, and these particles seize the nutrients of the leaves, preventing the leaves from growing normally and causing the leaves to turn black. The causes of powdery mildew are mainly related to temperature and humidity and density. Pay attention to the temperature and humidity of the watermelon. Reasonably arrange the drainage system and planting density in the watermelon field, pay attention to drainage after rain, and base fertilization mainly on organic fertilizer. Powdery mildew is mainly controlled through prevention.
The above five are several common diseases of watermelon. Among them, special attention should be paid to gray mold, because gray mold is difficult to control and prevent, and if not handled in time it can lead to a total loss with no harvest at all. In fact, diseases are all closely related to temperature, humidity and density. As long as these are reasonably controlled, the probability of disease occurrence will basically be much lower.