(1) promotes flower bud differentiation. Some varieties grow excessively in hot areas under high temperature and high temperature conditions. The following measures should be taken to promote flower bud differentiation: selecting rootstocks with early fruiting and high yield; Timely release autumn shoots and cultivate a large number of robust fruit branches; Proper control of water during flower bud differentiation; Take technical measures such as root cutting, ring cutting and branch bending; Apply plant growth regulators (such as spraying b 1000-2000mg/L on autumn shoots). Or pp333500mg/l); Picking fruits in stages at the right time; And in the middle and late June 10, full-fertilizer composting, phosphorus spraying and potassium spraying in autumn and winter, etc. (2) Protecting flowers and fruits is aimed at the main reasons of citrus falling flowers and fruits (abnormal flower development or poor fertilization; This tree is malnourished; A large number of summer shoots compete with young fruits for nutrients and water; Bad weather during flowering or young fruit; Serious pests and diseases. ). The main measures to protect flowers and fruits are: rational fertilization (a certain amount of quick-acting fertilizer should be applied according to the size and growth potential of trees before spring shoots germinate 15 days, and withering fertilizer should be applied again after flowers wither, and 0.3%-0.5% urea +0. 1% boric acid or 0.3% should be sprayed at flowering stage and young fruit stage respectively. Irrigation and drainage in time (in case of drought in spring shoot germination, irrigation should be done in time, and drainage should be paid attention to in summer. In case of high temperature and drought for more than 7 days, it is necessary to irrigate or spray water to prevent the fruit from falling); Control overgrowth of spring shoots and summer shoots. Application of girdling or girdling technology (healthy middle-aged and young fruit-bearing trees begin to drop fruit after flowering, girdling or girdling is carried out on the trunk or main branch, and the flourishing trees are carried out again on 15d); Plant growth regulators (spraying gibberellin 50mg/L after flowering, spraying again after 20d, or adding chlorfenapyr and chlorfenapyr containing nucleotides, or using 2.4-D5mg/L+0.3% urea +0.2% potassium dihydrogen phosphate) are used to prevent and control pests in time.