What are the control methods for the jujube rust mite?
Jujube trees are generally more common in the north and relatively rare in the south. For friends who grow jujube trees, the thing they fear most is the damage of pests. Once a jujube tree is attacked by pests, not only will the yield decrease, but the fruit produced will be bitten and damaged by insects, and in more serious cases it will even cause the jujube tree to wither.
Control of the jujube rust mite
The jujube rust mite is commonly known as the jujube rust mite. It damages jujube and wild jujube. Adults and nymphs pierce and suck sap to feed on green parts such as leaves, flower buds, flowers, young jujubes, and deciduous branches; the damaged parts either show silvery-gray rust spots or dry up and fall off, and severely affected trees or plots can suffer total crop loss.
Adult mite: body length about 0.15 mm, wedge-shaped; initially milky white, later light brown, semi-transparent; 2 pairs of legs, located on the anterior body segment; thoracic plate shield-shaped; mouthparts slender and pointed, curved downward; the dorsal and ventral surfaces of the posterior body segment have an annulated structure, with about 40 rings on the dorsal side, each of the front, middle, and rear having 1 pair of stout setae, and the end having 1 pair of equal-length tail hairs. Egg: spherical, milky white, surface smooth, glossy. Nymph: body white, semi-transparent when newly hatched; body shape similar to the adult mite.
The jujube rust mite overwinters as adult mites in the old bud scales of jujube spurs. In mid-April of the following year, during the jujube budding period, the overwintering adult mites emerge from dormancy and become active, damaging tender buds and young leaves. In early June, when the jujube tree is in the flowering period, it enters the peak damage period, and the damage symptoms begin to appear. In mid-June, the population density is the highest, and throughout June this pest mite reproduces fastest, making it the annual peak occurrence period. From mid-July to August, during the high-temperature stage, the vast majority of mites move into the old bud scales of jujube spurs to oversummer, and the number of mites on leaves decreases significantly. In September, the reproduction rate declines, and the population density is the lowest; by the end of September, all have entered dormancy to overwinter. The annual damage period lasts 5 and a half months. After leaves are damaged, at first the leaf base and areas along the leaf veins first show mild grayish-white; as the mite population density increases, the symptoms gradually spread over the entire leaf, the leaf color becomes extremely grayish-white and aged, the leaf texture becomes thick and brittle, and the leaf slightly folds toward the upper surface along the midrib; in the later stage, the leaf margins scorch, often causing premature leaf drop. After flower buds and flowers are damaged, they gradually turn brown, dry up, and fall off. After fruit is damaged, silvery-gray rust spots appear, and in the later stage the fruit wilts and falls off.
Control methods. At the end of May or early June, when the jujube tree begins flowering, spray 40% omethoate emulsifiable concentrate at 1500 times dilution or 20% dicofol emulsifiable concentrate at 1000 times dilution. These two agents of different natures are best used alternately, which can delay the development of resistance in this pest mite. Bordeaux mixture or 0.3-0.5 degree Baume lime sulfur mixture can also be sprayed. When spraying, attention should be paid to spraying the inner canopy and the underside of leaves. As long as spraying is timely, thorough, and careful, the occurrence and damage of this mite can be controlled, ensuring the yield and quality of jujube fruit.
Disease and pest control of jujube
1. Diseases: For jujube witches' broom, trunk injection with 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 below 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 apply triadimefon or thiophanate-methyl once; 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 Bordeaux mixture once, and other diseases can be controlled.
2. Insect pests: For the jujube gall midge, after germination in spring, before leaf curling, use dichlorvos plus diflubenzuron for control. About 10 days after the first generation occurs, spray again generally once, and the occurrence of subsequent generations can be controlled. For scale insects, around wheat harvest, when newly hatched larvae crawl out from the mother body and the wax shell has not yet secreted wax, this is the key period to use omethoate for control. When the jujube stink bug occurs, use deltamethrin emulsifiable concentrate for control. When the jujube looper and slug moth 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 bore holes, inject dichlorvos emulsion or pyrethroid pesticides into the bore holes with a syringe, and plug the bore holes with mud, which can kill the longhorn beetle larvae.
Growth habits of jujube trees
Jujube trees grow in mountainous areas, hills, or plains below 1700 m altitude. They are a temperature-loving fruit tree, with an average annual temperature in production areas of about 15°C. The temperature during bud break needs to be 13-15°C, during shoot growth and leaf expansion 17°C, during flowering and fruit setting 22-25°C, and during fruit ripening 18-22°C. Jujube trees are relatively strong in drought tolerance and waterlogging tolerance, but the flowering period requires relatively high air humidity, otherwise pollination and fruit setting are unfavorable. In addition, jujube has strong light requirements, is relatively sensitive to light response, has strong adaptability to soil, and tolerates poor soil and salinity-alkalinity. However, it fears wind, so when establishing an orchard, care should be taken to avoid wind gaps.
How to protect flowers and fruits in jujube trees
1. Inhibit vegetative growth, regulate the contradiction between growth and fruiting, and promote fruit setting. Such measures include root cutting, pinching, bud removal, branch thinning, girdling, ringing, scoring, and fertilizer and water management. Taking these measures can regulate the contradiction in nutrient distribution and transport between vegetative growth and flowering and fruiting in the tree body, improve the nutritional level of the tree body, and allow more nutrients to be supplied to the needs of flowers and fruits.
2. Spray water during the flowering period to increase air humidity. During the flowering period, air humidity should not be lower than 60-70%, otherwise it will have an effect. Spraying in the evening or morning gives good results, generally combined with foliar fertilizer spraying of 0.3-0.5% urea.
3. Place bees in the jujube orchard to increase pollination vectors. Some jujube varieties are self-pollinating and some are cross-pollinating. Pollination within a variety or between varieties can both achieve good fruit setting, and increasing pollination vectors has a good effect.
4. Spray plant hormones and trace elements, mainly gibberellin, 2,4-D, paclobutrazol, chlormequat, B9, indolebutyric acid, indoleacetic acid, acetic acid, naphthaleneacetic acid, borax, boric acid, etc.
Therefore, when fruit farmers plant jujube trees, they should not blindly plant in one way. Before planting, they should first understand the growth habits of jujube trees, and most importantly, understand the prevention and treatment methods for various diseases and insect pests, so as to avoid being in a rush in actual planting.