What are the remedial measures after late frost damage?
1. Carry out artificial supplementary pollination in a timely manner. If the late frost occurs relatively early and the temperature drops below 0°C, the flowers that are opening or have already opened suffer severe low-temperature damage and have lost the ability to pollinate, fertilize and set fruit. At this time, after the frost, artificial pollination should be carried out on the unopened mid- and late-season flowers to increase the fruit-setting rate. If the late frost occurs relatively late and the low temperature of the frost is above 0°C, and the style and ovary show no change and still have the ability to pollinate and fertilize, then artificial pollination should be carried out promptly after the frost.
The picture shows: walnut
2. Foliar fertilization. After artificial pollination, immediately spray the tree canopy with a mixture of 0.3% borax, 0.3% urea and 1.0% sucrose to comprehensively increase the fruit-setting rate. When the flower organs are not damaged, spraying gibberellin can promote parthenocarpy and make up for a certain amount of yield loss.
3. Girdling or ring cutting. After the flowering period ends, ring cutting on the trunk of large trees or weak trees with many fruits, and trunk girdling on young trees or vigorous trees with few fruits, can both increase the fruit-setting rate and reduce the adverse effects of late frost on yield.
4. Strengthen comprehensive tree management. Strengthen comprehensive management of soil, fertilizer and water, especially timely additional application of fertilizer and water and foliar topdressing, to nourish the roots and strengthen the tree, so that the tree body can recover its vigor as soon as possible, promote fruit development, increase single fruit weight, and recover yield.
In addition, after the tree body suffers late frost damage, the tree body becomes weak and has poor resistance, making it prone to pest and disease damage. Therefore, attention should be paid to strengthening comprehensive prevention and control of pests and diseases to minimize yield and economic losses caused by pest and disease damage; at the same time, pay attention to summer pruning and autumn fertilization to improve the level of stored nutrients in the tree body and lay the foundation for a bumper harvest the following year.