The fruit of litchi and longan should be preserved early.

After the influence of cold weather in late spring with low temperature in mid-March, most areas of Maoming rarely had sunny days from 19 to 22, and rainy weather began to appear on 23. At present, litchi flowers are in full bloom season, longan flowers are also blooming one after another. The rainy weather during flowering is very unfavorable to the flower organ development, pollination, fertilization, flowering and fruit setting of litchi and longan. If in accordance with the habits of previous years, Xie Hua only after the start of fruit protection is easy to cause serious fruit drop. Therefore, in rainy weather during flowering period, litchi and longan fruit protection work should be carried out early, and effective measures should be taken in time to improve fruit setting rate and reduce physiological fruit drop after fruit setting. I. Spray fertilizer on sunny days and seize the opportunity to supplement nutrition Litchi and longan flowering period is a period of large consumption of nutrients. In rainy weather, the photosynthesis effect of leaves is poor, and the nutrient supply is insufficient, so it is necessary to supplement organic nutrition in time. Organic fertilizer is applied on the ground, absorption and delivery are slow, it is difficult to rescue, and foliar nutrition needs to be supplemented. However, it is difficult to spray foliar fertilizer in rainy weather, so we should seize the opportunity to spray it when it is sunny and supplement nutrition in time. Otherwise, it is easy to miss the opportunity, and the fruit can not find the ideal weather to supplement nutrition. Spraying foliar fertilizer is mainly organic nutrition, and various foliar fertilizers can be used alternately. Second, do a good job of auxiliary pollination pollination fertilization is litchi, longan from flower to fruit a key link. When the weather is fine, litchi, longan pollen blowing through the breeze to the style can also pollinate fertilization. However, it is difficult to pollinate and fertilize litchi and longan in rainy weather, so it is necessary to do a good job of assisted pollination and fertilization to improve fruit setting rate. In rainy weather during flowering period, artificial methods should be adopted when it is slightly sunny. Tie wire wrapped in cloth should be shaken to shake branches, shake water drops accumulated on flowers, accelerate pollen drying and distribution, and increase the chance of pollination and fertilization. At the same time, contact beekeepers to release bees in orchards, or hang wet rotten fish or fish viscera in orchards to attract pollination insect vectors such as flies, and assist pollination through bees or other pollination media. Artificial pollination can also be carried out. The simplest method is to wash the branches of male flowers in a basin at about 10 a.m., filter the water until it is dark brown, and then spray it on the trees with female flowers. Third, take measures before Xie Hua to reduce the first batch of physiological fruit drop Due to the influence of bad weather in spring, the flower quality of litchi and longan is weak, the flower organ is poorly developed, and it is easy to cause pollination and non-fertilization when flowering, or "false fertilization". After Xie Hua, it seems that there are more fruits, but the color is yellow, not delicate enough, and soon a large number of physiological fruit drops occur. Either the seeds of the fruiting fruit do not develop, or the seeds of the fruiting fruit are "hollow" and will fall off sooner or later during development. The above fruit drop phenomenon will be more serious in rainy weather during flowering. Therefore, measures should be taken to protect the results before the flowers are thanked. Litchi and longan can be sprayed together with foliar fertilizer plus 2,4-D and 920 growth regulators (to be used according to instructions) to stimulate seed development and make fruits develop normally. For stronger litchi, a ring can also be added to protect fruits. IV. Prevention and control of pests and diseases When the weather turns clear and the temperature rises, it is conducive to the activities of pests and the occurrence of diseases. when the temperature rises again, we should focus on preventing and controlling pests such as borers. According to the results of the test, the pesticide should be sprayed at the adult emergence stage and larval stage. Trichlorfon plus dimefon or litchongqing, biqiaoling, cypermethrin and other pesticides can be selected. After rainy days, humidity is too high, temperature rises, it is easy to occur downy mildew and anthracnose. You can choose Pujunte, Yibao, Chuangtan Jing, methyl thiophane and other drugs in the weather when the weather turns fine combined with foliar fertilizer and pesticides together control.