A Detailed Guide to 5 Common Diseases in Watermelon Cultivation and Their Control Methods

Watermelon is a very popular staple fruit, but during cultivation it is very sensitive to the surrounding growing environment, and it will encounter many diseases during its growth process, and a single careless moment may endanger an entire watermelon field. Below, we introduce Watermelon Cultivation: A Detailed Guide to 5 Common Diseases and Their Control Methods!

I. Watermelon Phytophthora Blight

Watermelon phytophthora blight usually occurs in the hot, rainy season. Poor drainage systems in watermelon fields and planting that is too dense can both trigger it. It harms the roots and stems of watermelons, and in severe cases also affects the leaves, fruit and vines. When it occurs at the root crown, dark green patches appear, and the patches develop around the stem, causing the stem to rot, ultimately causing the entire plant to wither and die. The symptoms on leaves, fruit and vines are similar.

Control methods: Before sowing, disease-resistant varieties can be selected, such as Qiongxue. Never rotate with melon and fruit vegetables after the watermelon field is harvested. Diseased melons should be removed promptly to prevent transmission. When melons are affected, sprays can be applied for control, such as cymoxanil mancozeb, sprayed once a week for about one month.

II. 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 the greater amount of rainy weather. Leaf blight mainly harms the leaves, followed by the vines and fruit. It mostly occurs on young leaves, producing irregular brown patches on the young leaves; continued growth causes the leaves to wither. When it occurs on fruit and vines, the fruit and vines rot.

Control methods: There are specialized disease-resistant varieties on the market that resist leaf blight, such as Zhengza No. 7. After harvest, pay attention to cleaning up diseased melons and burning them in a centralized manner. Establish a good drainage system for the watermelon field, and pay attention to rain protection during rainy weather. Before disease spots appear, spray with procymidone wettable powder for control, once a week for about one month.

III. Watermelon Fusarium Wilt

Fusarium wilt generally occurs at the fruiting stage. Seedlings stand upright in a withered 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 within 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.

Control methods: The best way to control fusarium wilt is to graft watermelon onto crops that are not prone to fusarium wilt, such as gourds. Disease-resistant varieties on the market include Xinong No. 8. To prevent fusarium wilt, you can rotate with aquatic crops in the watermelon field, because the fusarium wilt pathogen survives in water for only just over 100 days. Finally, choose soil rich in nutrients, and do not use fertilizer containing diseased plant residues.

IV. 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 the leaves, fruit and stems. On the leaves it produces gray irregular patches, ultimately causing withering. Gray patches also appear on the fruit and stems, preventing the fruit and stems from growing normally and producing deformed fruit. 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 be deformed and impossible to sell.

Control methods: Wuyi mycin aqueous solution and anti-mold wettable powder can be used for spraying, once a week for about one month. Rotation should be at least more than 4 years, and abundant organic fertilizer should be used.

V. Watermelon Powdery Mildew

Powdery mildew occurs more severely mainly in autumn in the south. It mainly harms the leaves and generally has little effect on the fruit. It produces many small white particles on the leaves, and these particles rob the leaves of nutrients, preventing the leaves from growing normally and causing the leaves to turn black.

Control methods: The causes of powdery mildew are mainly related to temperature, 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 rainfall, and base fertilization mainly on organic fertilizer. Powdery mildew is mainly controlled through prevention.

The above is Tuliu.com's introduction to five common diseases of watermelon. Among them, special attention should be paid to gray mold. Gray mold is difficult to control and prevent, and if not handled in time it can lead to total crop 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 onset will basically be much lower.