When do jujube trees usually bloom and drop their leaves, and what should be sprayed for yellow leaves?

Jujube trees grow in mountainous areas, hills or plains below 1700 m in altitude. They are widely cultivated. This species is native to China, and is often cultivated in Asia, Europe and the Americas. So when do they usually bloom and drop their leaves? How is it treated? What should be sprayed? According to Rhamnaceae data, jujube flowers are yellow-green, bisexual, hairless, with short common peduncles, solitary or densely clustered in axillary cymes. The flowering period is May to July, and the fruiting period is August to September. Jujube trees generally begin to drop their leaves in late October and finish dropping them around mid-November.

How are yellow leaves on jujube trees treated?

1. Strengthen management, deep-plow the soil, apply more organic fertilizer, and bury sulfur under the tree, which can regulate the pH of the local soil and also sterilize and kill insects

2. When watering, citric acid, glacial acetic acid, boric acid, phosphoric acid, etc. can be added to the water and fertilizer to adjust the pH value of the water, making it more acidic; when the soil and water are more acidic, plants can more easily absorb iron ions, and the probability of chlorosis will be reduced;

3. According to the size of the tree, combined with autumn fertilization, apply 100-250 grams of ferrous sulfate as a topdressing to each jujube tree;

4. During the shoot-sprouting and leaf-unfolding period of jujube trees, supplement iron by foliar topdressing in the morning and evening, spraying a 1000-fold aqueous solution of ferrous sulfate on the leaves so that the leaves absorb it directly. Spray once every 10 days, for 3-5 consecutive sprays.

What should be sprayed on jujube trees?

Diseases:

For jujube witches' broom, trunk injection of Zaofeng No. 1 and Zaofeng No. 2 can cure diseased trees in the same year, and they will bear jujubes in the second year. For fruit shrinkage disease, regular spraying of compound Zaohongbao can reduce the incidence of fruit shrinkage disease from more than 80% to less than 15%. For other diseases, before germination spray the whole orchard, both on and under the trees, with 5 degrees Baume lime sulfur mixture; in mid-to-late June spray once with triadimefon or thiophanate-methyl; in early July spray mancozeb, carboxin, or triadimefon emulsifiable concentrate once every 15-20 days, for a total of 2-3 times; in late July spray once with Bordeaux mixture, and other diseases can be controlled.

Insect pests:

For jujube gall midge, after germination in spring, before the leaves curl, use dichlorvos plus diflubenzuron for control. About 10 days after the first generation occurs, spray again generally once, and later generations can be controlled. For scale insects, around wheat harvest, when newly hatched larvae crawl out from the mother body and the waxy shell has not yet secreted wax, use omethoate for control during this key period. When jujube stink bugs occur, use deltamethrin emulsifiable concentrate for control. When jujube loopers and slug moths occur, use pyrethroid pesticides for control. For longhorn beetles, from July to October, use a small iron shovel to remove the surface soil around the root crown, find the longhorn beetle holes, inject dichlorvos emulsion or pyrethroid pesticides into the holes with a syringe, and plug the holes with mud, which can kill the longhorn beetle larvae.