How to identify and control jujube witches' broom? The methods explained clearly in one article

Jujube witches' broom, commonly known as "male jujube tree", is a devastating disease of jujube trees. In severe cases, it can cause mass death of jujube trees and even destroy the entire orchard.

1. Symptom identification

(1) The initial symptoms appear after flowering, manifested as degeneration of floral organs and abnormal sprouting of buds; the leaves that grow out are narrow and small, forming clustered branches and leaves, and the young leaves show vein clearing, yellowing and curling into a spoon shape. (2) The leaves of diseased trees show obvious pathological changes after flowering: first the mesophyll turns yellow, then gradually the entire leaf yellows, the edges curl upward, and later the leaves become hard and brittle, dull and lusterless. (3) Most of the normal buds on the 1-year-old vegetative shoots and the latent buds on the perennial vegetative shoots of diseased plants sprout and develop into vegetative shoots; diseased flowers generally cannot set fruit; even if they do set fruit, it has no economic value. (4) In the later stage, the cortex of diseased roots turns brown and rots; diseased trees bear no fruit until the whole plant dies.

2. Occurrence pattern

Jujube witches' broom can spread through grafting and root division. Through grafting transmission, the incubation period of the disease is from 25 days to more than 1 year. Jinsixiaozao is the most susceptible. Jujube orchards with dry, barren soil and extensive management have severe incidence of the disease.

3. Control measures

Agricultural control: (1) Remove diseased branches and eradicate diseased plants with no economic value. (2) Select disease-resistant sour jujube varieties as rootstock. (3) Cultivate disease-free seedlings. That is, collect scions, graft buds or root divisions from jujube orchards free of jujube witches' broom for propagation, so as to cultivate disease-free seedlings. (4) Strengthen orchard management and apply more alkaline fertilizers and farmyard manure.

Chemical control: (1) In the early stage of the disease, use a hand drill to drill a hole in the root-collar part of the diseased tree, and in the spring budding period of jujube trees or in October, inject 500 milliliters of 0.1% tetracycline solution per diseased tree by drip infusion. (2) Drill 1 hole on each side of the trunk base or the middle-lower part at a place without scars, reaching deep to the pith, with a vertical distance of 10-20 cm between the two holes, and inject oxytetracycline solution containing 10,000 units with a high-pressure syringe. For trunk circumference of more than 30 cm, use 300-400 milliliters of the solution; for more than 40 cm, use 500-700 milliliters; for more than 50 cm, use 800-1000 milliliters; for more than 60 cm, use 1200-1500 milliliters. (3) In the early stage of the disease, spray 0.2% ferric chloride solution 2-3 times per 667 sq m of jujube orchard, with an interval of 5-7 days between sprays. Use 75 kg-100 kg of the solution each time, which has a good effect on preventing jujube witches' broom.