Five key points for winter management of citrus, fruit growers must remember
After the citrus fruit is harvested, because the tree body has consumed a large amount of nutrients in bearing fruit, nutrients need to be supplemented to restore tree vigor. At the same time, winter is also a critical period for citrus flower bud differentiation and for pests and diseases to overwinter. Therefore, strengthening winter management is the basis for a bumper harvest next year and for reducing pest and disease damage.
1. Apply base fertilizer early. In order to favor citrus flower bud differentiation, improve flower bud quality, increase tree body nutrients, and improve cold resistance, base fertilizer must be applied early. Bearing trees can be fertilized one week after fruit harvest, and young trees must be fully fertilized in November. The earlier the fertilizer is applied, the higher the temperature, which favors fertilizer decomposition and tree body absorption, and the fertilization effect is good. This fertilization is mainly organic fertilizer, matched with special fertilizer for fruit trees, and can be applied by the ring ditch and strip ditch methods.
2. Dig ditches for drainage and prevent waterlogging damage. This autumn, due to continuous overcast and rainy weather, the field humidity is high, and citrus is intolerant of waterlogging. If there is much soil moisture, the soil root system is prone to mildew and rot, causing leaves to turn yellow, leaf drop, and in severe cases causing tree death. Therefore, in conjunction with fertilization, dig ditches in time to drain moisture and shape the tree strips, making future management easier.
3. Clean the orchard in time. The sources of diseases and insects harmful to citrus all overwinter in dead branches and fallen leaves, weeds, and fallen fruit. Therefore, in early winter (mid-November), promptly clean all diseased and insect-damaged branches, dried and dead branches, fallen leaves, fallen fruit, and weeds completely out of the orchard, and burn them in a centralized way or bury them deeply. At the same time, all late autumn shoots issued after September 20 must be pruned off to prevent the late autumn shoots from extending and growing, which reduces the cold resistance of the tree body.
4. Pest and disease control. After cleaning the orchard, starting in late November, spray the leaves once a month with 45% lime sulfur mixture at 180-300 times dilution, once a month for 3-4 consecutive sprays, which can effectively control overwintering anthracnose, mites, scale insects and other pests and diseases, reduce the pest and disease base, lower the number of pesticide applications next year, and improve production efficiency.
5. Strengthen freeze protection. Freeze damage has a great impact on the citrus tree body and next year's yield. It can be prevented by whitening the trunk and covering the tree disk (tree strip) with plastic film or (rice straw). Trunk whitening can both prevent freezing and control trunk pests and diseases. Use 72% water, 22% quicklime, 3% lime sulfur mixture, and 3% table salt, stir, and apply evenly for whitening. It is best if after application it does not flow downward and does not clump together. The quicklime must be fully dissolved, otherwise it will absorb water and release heat and burn the trunk. Freeze protection measures must be completed by early December to enhance the freeze protection effect.