西瓜是经济作物中面积较大的一种。目前,西瓜生产上存在以下问题,影响产量的提高:①病虫危害,难抓全苗。即使获得全苗,也因病虫继续危害,难保全苗。②目前,西瓜生产上有机肥普遍不足,瓜农大量增施氮、磷化肥,土壤中有效态微量 Watermelon is a large area of ​​cash crops. At present, watermelon production has the following problems, affecting the yield increase: ① pest damage, difficult to grasp the whole seedlings. Even if the whole seedlings, but also because of pests and diseases continue to endanger, it is difficult to protect the whole seedlings. ② At present, the general lack of organic fertilizer in the production of watermelon, melon farmers increased nitrogen and phosphorus fertilizer, the effective amount of soil trace