Cross stitch of watermelons is a physiological disorder (not caused by an infectious disease) first reported in 1990s on watermelon fruit. It received the name because the symptom looks like cross stitch. One or more rows of oval-shaped lesions lie along with the longitudinal axis of the fruit. These lesions are normally more close to the stem end of the fruit (Figure 1). Sizes of the lesions range from a quarter inch to more than 2 inches. When the lesions are small, it normally does not affect interior flesh quality. However, if lesions develop into large gaps, it could lead to fruit rot (Figure 2).
Figure 1. Cross stitch on watermelon fruit.
Figure 2. Cross stitch with large lesions.
Cross-stitch symptom has been noticed in several watermelon production areas, however, causes of the symptom is still largely unknown. In most of the years, this is a minor problem. However, we have received more reports of cross-stitch on watermelon fruit this year. In one case, more than 10% of fruit were affected. While we are gathering more information to better understand the physiological disorder, we would appreciate it if you would let us know if you see the symptom on your watermelons.