A significant threat to your watermelons might just be a microscopic roundworm. Yes, I’m referring to nematodes of watermelon. Watermelons afflicted with nematodes yellow, become stunted and generally decline. Watermelons and other cucurbits are primarily susceptible to root nematodes but can also be damaged by sting nematodes. How do you go about controlling watermelon nematodes? The following article contains information about watermelon nematode treatment.
Symptoms of Watermelons with Nematodes
Nematodes live in the soil and feed on the roots of plants, reducing their ability to absorb water and nutrients and leading to a general decline in their health and productivity. Not only does nematode feeding weaken the plant, but it can also predispose plants to fungal or bacterial disease or transmit viral disease.
In watermelons with nematode damage, leaf chlorosis is evident and leaves may be stunted and wilted. Roots may form galls where the nematodes hide, feed and reproduce.
In large watermelon patches, nematodes of watermelon may only afflict a portion of the field, leaving some plants unscathed. Depending upon the type of nematode feeding, yields may be extensive but vary depending upon species. In the case of watermelons, root nematodes rarely cause damage in areas that have had long grass growing rotations. Thus, in soil where nematode host plants have grown in the last 3-5 years, the incidence of nematodes of watermelon rises.
Nematodes are notoriously difficult to control, so how do you go about controlling watermelon nematodes? Because they are microscopic, it is a good idea to have soil and root tissue samples tested to determine if nematodes are the cause of symptomatic plants. Testing needs to be done before planting since once the nematodes become established in the watermelon patch.
Of course, if planting has already occurred and symptoms appear to indicate nematodes, a quick test for root knot nematodes is to look at the roots of the plant. Root knot nematodes cause galls to form on roots and are readily evident if they are the culprit.
Management of areas infested with nematodes includes crop rotation with less susceptible crops or resistant varieties. Also, pre-plant nematicide treatments can be applied. Most nematicides are soil applied and incorporated into the top 3-6 inches (8-15 cm.) of soil. They have limited residual activity and are often used in conjunction with other cultural or chemical pest control.
Both of these management practices are just that, management. They will help to reduce the nematode population and improve crop production but not rid the area entirely of the nematodes.