How to prevent and control jujube witches' broom? Remember these ten key points

Jujube witches' broom, also known as witches' broom disease, is a devastating disease of jujube trees. In infected jujube trees, the flowers degenerate and become deformed, the branches and leaves are small and clustered, and the leaves are wrinkled and do not spread out, causing a large number of plants to stagnate in growth or die. When preventing and controlling it, pay attention to the following ten key points:

1. Do a good job of quarantine at the nursery site. When developing a new jujube orchard, if propagating on site, the roots connected to the mother plant should be cut off as early as possible. Introduced seedlings must be strictly quarantined, root suckers from disease-free mother plants should be selected for propagation, and disease-free rootstocks and scions should be used for grafting, so as to ensure strict quarantine at the production site.

2. Pay attention to disinfecting grafting and pruning tools. For disinfection, alcohol, fire or potassium permanganate solution can be used to avoid cross-infection.

3. Strengthen the cultivation management of jujube trees. Through reasonable pruning, the branches of jujube trees should be fully exposed to light and have good ventilation, and pruning in spring and summer is equally important. Apply more high-quality decomposed organic fertilizer and phosphorus and potassium fertilizer in the jujube orchard. In calcium-deficient soil, calcium fertilizer should be applied, and weeds should be removed in time.

4. For mildly diseased trees, medicine can be injected through holes. In August, 2 to 3 holes can be drilled in the trunk on the same side as the diseased branches of mildly diseased jujube trees with witches' broom, deep enough to reach the xylem. Use 50 grams of menthol, 100 grams of dragon bone powder and 50 grams of copper green, mix them and grind them into fine powder, send it into the holes with a paper tube, 3 grams per hole, then drive in wooden wedges tightly, and then seal with mud for prevention.

5. In summer, apply wheat bran in ring-shaped trenches. In July, ring-shaped trenches can be dug around the jujube trees, and about 3 kg of wheat bran can be applied per tree. After watering, cover with soil, which can improve the disease resistance of jujube trees.

6. Actively treat mildly and moderately diseased trees. For jujube trees with mild disease, before sap flow in early spring, inject 100 ml of 10 million units of oxytetracycline in 4 directions at the base of the trunk using a trunk injection machine, and inject once more in autumn before the sap returns to the roots.

7. Perform girdling on the main trunk and main roots. From leaf fall of diseased jujube trees to before sprouting the following year, saw out 3 to 5 ring-shaped grooves starting from 40 cm above the ground on the main trunk and going upward (spacing between ring-shaped grooves 15 to 20 cm), cutting through the bark but not damaging the xylem. Around the roots of severely diseased trees, dig away the soil to expose the base of the main roots, and saw out ring-shaped grooves at the base the same as those on the main trunk, cutting off the phloem sieve tubes so that the pathogen cannot survive.

8. Cut off some lateral roots of severely diseased trees. For severely diseased jujube trees, cut off the lateral roots on the same side as the diseased branches, so as to eliminate the pathogen overwintering in the lateral roots of the diseased trees and prevent the pathogen from spreading.

9. Control disease-transmitting insects and cut off the transmission route. Do not plant trees such as pine, cypress, mulberry and paulownia near newly built jujube orchards, and intercropping with sesame is strictly prohibited to reduce the number of vector pests. According to insect situation forecasting, while controlling jujube geometrid, jujube leafroller and peach fruit borer, control leafhopper vector insects. Different pesticides should be sprayed at different developmental stages of the transmitting insects. For example, when jujube trees sprout (around late April), spray 1000 times 50% methyl parathion 1605 to control the overwintering eggs hatching of Chinese false diamondback leafhopper; before flowering (around mid-May), spray 10% cypermethrin emulsifiable concentrate 5000 times to control the first-generation nymphs of Chinese false diamondback leafhopper and concave-margined diamondback leafhopper; after full bloom (around late June), spray 50% fenitrothion emulsifiable concentrate 1000 times, or 50% dichlorvos 1000 times to control adults of Chinese false diamondback leafhopper; in mid-July, spray 20% fenvalerate emulsifiable concentrate 3000 times to control Chinese false diamondback leafhopper and concave-margined diamondback leafhopper.

10. Prune off lightly diseased branches and dig out severely diseased trees. During the peak incidence period of jujube witches' broom in July and August, remove diseased buds in time. For mildly diseased jujube trees, saw off the diseased branches from the base as early as possible (that is, for small witches' broom branches saw off the large branch, do not saw off only the small branch part), and burn and bury the diseased branches and diseased leaves together; severely diseased jujube trees should be completely dug out, including the roots, and after thoroughly cleaning up dead branches and residual roots, burn them together to prevent root suckers from sprouting, so as to reduce the source of disease. Remove diseased wild jujube plants within a 300 m radius of the jujube orchard to avoid cross-infection.