Many nematode, insect, and disease pests affect watermelons. Some of these pests such as fusarium wilt cannot be controlled by spraying. Resistant varieties in conjunction with rotation to land that has been out of watermelon production for at least 8 years is an effective control measure. Other serious diseases include anthracnose, gummy stem blight, cercospora leaf spot, alternaria leaf spot, and downy mildew which can be controlled with fungicide sprays. There are many insects that can cause damage to watermelons including cutworms, mole crickets, leaf miners, aphids, and rindworms.
Control includes timely scouting of fields and application of proper insecticides.
Weed growth and competition can be severe. At the present time, adequate weed control can be obtained only through the combined use of good field preparation, herbicides, and cultivation. Watermelons require insect pollination for fruit set and proper development of fruit shape and size. Honey bees are the most dependable pollinators when properly managed and tend to collect pollen from a single species of flower that is near their hive. Use one active hive of bees for every 3 to 5 acres of watermelons.