You're talking about water holding melons. The main reason is that the fruit can't absorb and transform after absorbing a lot of water because of flooding or excessive rainfall at maturity. Applying a large amount of nitrogen fertilizer in the late growth stage can also cause the disease. This kind of melon has poor taste and short shelf life, which seriously affects its commercialization. It should be harvested in time, and the fruit should not be flooded in the later stage of maturity. In case of rainy days, the accumulated water in the field should be removed in time, and the well-drained sandy loam land should be selected for planting. Reasonable application of nitrogen fertilizer, no longer applying nitrogen fertilizer in the late stage of fruit ripening, and timely supplementation of potassium and calcium have good effects on preventing and controlling this phenomenon.