Methods for Preventing and Controlling Pests and Diseases of Winter Jujube Trees in Autumn and Winter, and Key Technical Points

After the beginning of autumn, winter jujube trees gradually enter the dormant period, and their tolerance to chemicals is relatively high. As temperatures drop, pests and diseases enter bark cracks, scars, branch forks, fallen leaves, fallen fruit, mummified fruit or the soil, where they lurk to “overwinter”. Therefore, it is necessary to seize the favorable opportunity for pest and disease control in autumn and winter, and carry out pest and disease elimination in combination with cultivation management.

(1) Clean up fallen leaves. After the winter jujube trees shed their leaves, promptly sweep up dead branches, fallen leaves, diseased and mummified fruit, weeds and so on in the orchard, and bury them deeply or burn them in a centralized manner, so as to reduce the number of overwintering pathogens and pests.

(2) Deep ploughing of the jujube orchard. Especially in jujube orchards with poor soil and relatively high salt content, deep ploughing 15-20cm before the soil freezes can loosen the soil and preserve moisture, store rain and snow, promote root growth, and also turn overwintering pests in the soil up to the surface, where they are preyed on by natural enemies or freeze to death.

(3) Scrape old tree bark. In early winter or early spring, scrape off the old loose bark, diseased bark, insect-bored bark and so on at the trunk, large branches and branch forks, and burn or bury them deeply. This can effectively eliminate pests and diseases overwintering in the coarse bark. The scraping depth should be such that the bark layer is slightly exposed with a yellow-green color. After scraping, apply 40% asomate wettable powder at 10-100 times dilution or 5-10 degrees Baume lime sulfur mixture to the wounds to protect them.

(4) Whitewash the tree trunks. After the jujube trees shed their leaves, use whitewash on the trunk and the base of large branches to eliminate pests and diseases overwintering in the trunk. The whitewash can be prepared from 25 parts water, 10 parts quicklime, 1 part lime sulfur mixture, 1 part salt and a small amount of animal oil. An appropriate amount of fungicide and insecticide can also be added to the whitewash to increase its effect.

(5) Manual insect removal. After the jujube trees shed their leaves, in combination with winter pruning, cut off pest-damaged branches, and remove overwintering eggs, cocoons and so on of large bagworms, slug moths, cicadas and other pests from the branches.

(6) Spraying for prevention and control. After the jujube trees shed their leaves and before they sprout, spray once each time with 5 degrees Baume lime sulfur mixture plus 200 times sodium pentachlorophenate, which can eliminate overwintering pathogens and insect eggs.

(7) Bundling grass to trap and kill pests. After winter jujubes are picked, tie straw around the base of the trunk for one round to attract pests to overwinter in the grass, which can also prevent freeze damage. Before the jujube trees sprout in spring, untie the straw and take it outside the orchard to burn.

(8) Binding film to block and kill pests. In early spring, bind a ring of plastic film about 20cm wide around the base of the trunk, and use poisonous rope to tie around the middle of the film. Roll the film downward into a trumpet shape, which can effectively block and kill pests climbing up the tree.

(9) Mulching film over the tree dish. In early spring, covering the tree dish with plastic film can not only prevent pathogens and some pests on the ground from spreading to the tree, but also suppress weed growth, and can also raise soil temperature and reduce water evaporation.