In April and April, the temperature rose gradually and the air was dry. As early as the sweet grapefruit spider mite was seriously damaged, it had a great impact on the amount of flowers. This period of control of red spiders is the key to ensuring the amount of fruit this year. Control methods: (1) can be used Nisoxor 2000x + fluorene ketone 1000x spray; (2), can be 2000-2500 times 25% triazoni wettable powder; (3), available 2000 times 73% gefilte. Second, this period is the formation period of early pomelo buds, plants need a large amount of fertilizer, we must do a reasonable application of spring fertilizer. Fertilization method: Under the drip line of the plant ditch irrigation, one strain needs urea 0.25-0.5kg.