Control techniques of diseases and insect pests in jujube

If the planting of jujube wants to have a high yield, it is necessary to do a good job in the prevention and control of diseases and insect pests. It is the main reason for the low yield and poor quality of jujube, so timely control of jujube diseases and insect pests to ensure the healthy growth of jujube is the key to achieve a good harvest of jujube fruit.

I. main diseases and control measures

1.1 anthracnose of jujube

Jujube anthracnose, commonly known as "roast eggplant" disease, mainly harms jujube fruit, but also infects jujube hanging, leaf, jujube head and jujube stock. At first, brown water-stained spots appeared, and after enlargement, the disease spots became nearly round sunken spots, which expanded from dense gray to black particles, causing fruit drop, and the diseased fruit tasted bitter and unedible. The leaves will turn yellow and fall off, and the disease will be aggravated when it is rainy. The pathogen overwintered with mycelium on the residual jujube hanging and jujube head, and together with diseased berries became the initial infection source in the coming year. The conidia pile had water-soluble colloid, which could be spread only in dew and stormy weather under natural conditions.

Prevention and control measures:

⑴ combined with careful pruning: cutting off jujube hanging, disease and insect branches and withered branches, strengthening fertilizer and water management, improving soil, applying 50-60kg of rotten manure or human feces and urine per plant in late autumn and early winter, and applying 2-3kg of potassium sulfate compound fertilizer after rain in June to improve the disease resistance of trees.

⑵ chemical control: spray Baume 5-degree stone sulfur mixture once before jujube sprouting; eliminate the source of disease on the tree in late June before the disease period. The commonly used agents are 5000 times of 40% flusilazole EC and 1500 times of 50% isobacteria urea wettable powder; in conjunction with the prevention and control of jujube rust, spray a double Bordeaux solution or 10% polyoxymycin 1500 times in mid-late July.

1.2 jujube rust

An epidemic disease of jujube leaves caused by fungi that causes a large number of fallen leaves during fruit expansion. The disease mainly harms leaves and sometimes fruits. The damaged leaves scattered light green dots on the back, then gradually turned grayish brown, and finally the disease spots became yellowish brown, resulting in protruding summer spore piles. In the place where the leaves are facing the pile of summer spores, there are irregular small brown-green spots, which gradually lose their luster and become yellowish-brown corner spots. Most of the germs overwintered on the diseased leaves. After the rainfall in late June, the overwintering spores began to sprout and invade the leaves, and the disease began in the middle of July. The pathogen was continuously re-infected from August to September, and a large number of seriously damaged leaves began to fall. Rainy and high humidity are the main conditions for the epidemic of jujube rust.

Prevention and control measures:

⑴ should strengthen cultivation management: the newly built jujube garden should not be too dense, and the branches that are too dense should be pruned in time to facilitate ventilation and light transmission and enhance the tree potential. In the rainy season, attention should be paid to timely drainage to reduce the humidity of the jujube garden. Tall crops are not planted between rows, especially those that are often irrigated.

Application of fertilizer outside the root of ⑵: topdressing outside the root of jujube tree can not only improve photosynthesis and fruit setting rate, but also control jujube rust. During the susceptible period of jujube, 0.5% urea or 0.3% potassium dihydrogen phosphate solution can be sprayed for 2-3 times. Pay attention to cleaning the fallen leaves in winter and spring and burn them centrally to reduce the number of overwintering germs.

⑶ chemical control: in late June, the bacteria began to spray protection before invading, spraying once every 15-20 days, 3-5 times continuously. The commonly used agents are 50% carbendazim 600,800x, 200x Bordeaux solution, 25% trimethoprim wettable powder 800x-1000 times, etc., and the effect of alternate use is better.

1.3 Jujube Mad Disease

Local fruit growers also call it "broom disease" or "mad jujube tree", which is a disease caused by mycoplasma. The disease mainly harms jujube and wild wild jujube, and is a destructive disease of jujube. After the jujube tree was infected, both the aboveground and underground parts showed abnormal growth state. The aboveground part is manifested in the clustered branches and leaves caused by the change of leaves, abnormal bud development and growth, as well as the yellowing and curling of young leaves in the shape of spoons. The underground part is mainly manifested in the growth of roots and tillers. Young trees will die after 1-2 times of disease, big trees will get sick, and gradually wither and die in 2-3 years. Jujube mad disease is transmitted by grafting or by piercing of leafhopper pests in the field. In the initial stage of the disease, it is mostly from one or more big branches and root tillers, at the same time, there will be the whole plant at the same time.

Prevention and control measures:

⑴ selects seedlings without jujube mad disease, and seedlings imported from other places should be strictly quarantined. when grafting, disease-free rootstocks and scions are used, and grafting tools must be sterilized to prevent cross-infection of the disease.

⑵ can eradicate diseased plants and diseased roots and tillers to prevent infection, strengthen cultivation management, increase the application of alkaline fertilizer and rotten farm manure, and promote the healthy growth of trees.

⑶ control vector pests: spray 20% cyanoamathion 2500 times solution to control leafhopper pests.

1.4 Jujube seedling stem rot

Also known as jujube seedling root rot disease, jujube seedlings and nursery seedlings have occurred. When jujube seedlings grow to 3-9 leaves (usually in May-June in Tianjin), the stems and leaves are yellowish, and then pale, withered and die, but the withered leaves do not fall. Digging soil to observe the rhizome, it was found that there was dark brown rot in the cortex of the main stem, necrosis of xylem and pith, interruption of transport tissue and death of seedlings. The disease occurred in all jujube areas in the north.

Prevention and control measures:

⑴ increased the application of high-quality organic fertilizer to promote the healthy growth of seedlings, selected strong seedlings to plant, and improved the disease resistance of jujube seedlings.

The root of ⑵ was treated with pesticide. Irrigation with the mixture of 40% pentachloronitrobenzene wettable powder (3 ∶ 1) could not only prevent disease, but also promote root growth and improve disease resistance.

⑶ soil disinfection. During the sprouting period of jujube, 50% isobacteria ·thiram wettable powder was sprayed on the seedling bed to sterilize the soil.

1.5 jujube fruit shrinkage disease

Also known as jujube wilt disease, the pathogen only harms mature jujube fruit. The jujube fruit with fruit shrinkage disease first appeared yellowish-brown irregular discoloration spots on the shoulder or carcass, and then the pericarp appeared yellowish yellow, and in the later stage, the pericarp became dark red, contracted, and had no luster. The temperature of 26 ℃-28 ℃ is the peak of the disease, when the weather is rainy or rainy at night and sunny in the day, it is most likely to break out.

Prevention and control measures:

⑴ strengthens the soil management of jujube orchard, maintains soil moisture during the period from discoloration to red of jujube fruit, prevents the occurrence of fruit shrinkage disease, and strictly prevents fruit pests. Strengthen the control of leafhopper, tortoise wax scale and peach small solid insects in order to reduce the population density of fruit surface insects.

⑵ autumn garden cleaning: thoroughly remove disease, insect and rotten fruit, concentrate on burning or burying deeply, in order to reduce pathogens.

⑶ chemical control: before and after the disease of jujube, spray 2000 times of 12.5% diniconazole wettable powder or 8000 times of mancozeb wettable powder every 7-10 days, three times in a row. These potions had better be used now.

II. Main insect pests and control measures

2.1 Jujube gall midge

Also known as jujube maggot or jujube bud maggot, it is one of the main pests in jujube leaves. When the first generation of this insect occurs every year, it is in the period of sprouting and leaf expansion of jujube trees, and the larvae harm the young leaves of jujube trees that have not yet been developed and eat the sap on the surface of young leaves, resulting in a large number of young leaves that cannot be unfolded, the damaged leaves show light red to purplish red, the leaves are hard and brittle, and finally dry up and fall off, which is extremely disadvantageous to the flowering of jujube trees. The first ten days of May is the peak period of damage, and the mature larvae are buried in the soil after late August to make cocoons to survive the winter.

Prevention and control measures: the local fruit growers have insufficient understanding of the living habits and harmful characteristics of jujube gall mosquitoes, and can not grasp the critical period of its prevention and control, resulting in poor prevention and control effect. To this end, the effective prevention and control programs are:

⑴ artificial control: late autumn and early winter or early spring, turn the jujube garden deeply, turn the callus larvae and pupae into the deep soil, prevent it from emerging normally in spring, and eliminate overwintering adults or pupae.

⑵ ground poisoning: during the germination of jujube buds, before the adults fall off from the leaves before Eclosion, rake the ground once with 2.5% trichlorfon powder to poison the adults unearthed by Eclosion.

⑶ chemical control: focus on the overwintering generation and the first generation, spray fenpropathrin EC 2000 times, once every 10 days, continuous 2-3 times, the control effect is better.

2.2 Green blind bugs

Also known as small bedbug, it is a worldwide omnivorous pest, which harms the buds and buds of the host with the piercing mouthparts of adults and nymphs. After the young tissue of the plant is killed, it first appears dead spots, then turns yellow and wilts, the injured jujube hanging can not stretch normally, and the flower buds stop developing, resulting in withering. After the jujube tree germinates, the larva begins to endanger the tree. The leaf expansion period of jujube was the peak period in early May. After late May, the temperature increased and the insect population density decreased. 2-4 generations appeared from June to early August respectively.

Prevention and control measures:

⑴ killing eggs: planing tree plates in spring and autumn to eradicate weeds and eliminate overwintering eggs.

⑵ chemical control: after the overwintering eggs hatched in early spring, the overwintering crops were sprayed with 2000 times of fenpropathrin EC. Further chemical control was carried out in the first and middle of May and the first generation hazard period.

2.3 Peach heart borer

Also known as "jujube maggot", it is common in jujube producing areas in Tianjin. After eating into the fruit, the larvae latent food under the pericarp, and then eat to the jujube core. After 17 days in the fruit, the larvae mature, take off the fruit and form cocoons. If it is not controlled, the rate of insect pests can be as high as 40% Mui 60%, and the insect droppings will be kept in the fruit, seriously affecting the quality of the fruit. Two generations occur every year in Jizhou area, and the aged larvae are used as winter cocoons in the soil to survive the winter. in the following year, they are unearthed in the middle of May, unearthed continuously in the first and middle of June, and unearthed in the middle and late June. The adults emerged and laid eggs in July, and the larvae began to hatch and decay fruit in the middle of July. The larvae lived in the fruit for about 25 days, shed fruit and formed cocoons and pupae, and the second generation continued to occur. The second generation of fruit decay larvae continued after mid-July. After fruiting, most of them fall into the soil and form cocoons to survive the winter, and only one generation occurs.

Prevention and control measures:

⑴ plastic film mulching inhibited the emergence of larvae. In early June, mulching plastic film on the ground within 100cm around the tree trunk could inhibit the emergence, pupation and Eclosion of larvae.

⑵ picks up fallen fruit or shedding larvae. In early July or early August, picking up fallen dates can kill more than 80% of the larvae in the fruit in time. From August to September, the fruit larvae (most at the base of the trunk) can be picked up under the jujube tree and eliminated. Especially after the rain, there are more fruit-shedding larvae, which must be picked up in time and eliminated.

⑶ trees are sprayed to control fruit decay. Spraying on the tree is carried out during the period of adult Eclosion and egg incubation, which can be sprayed with 1500-2000 times of permethrin EC or 1500 times of thiazuron 3 suspension to kill adults, eggs and fruit-borer larvae.

2.4 jujube inchworm

Zaobuqu, also known as Zaobuqu, is one of the most important insect pests of jujube. Its larvae have strong overeating, endangering all green tissues such as jujube buds, leaves, jujube hanging, buds and so on. One generation occurs every year, and the pupa overwinters in the soil at the depth of 10-15cm around the canopy, then Eclosion into adults in late March of the following year, and then lays eggs after mating. The female adult does not have wings and must climb onto the trunk to lay eggs. After about 25 days of egg period, the larvae hatch from mid-late April to mid-May, and from late May to mid-June, they begin to pupate over the summer and winter.

Prevention and control measures:

⑴ digging overwintering pupae: capture the larvae before the middle of March, dig up the overwintering pupae and destroy them in the range of 100cm diameter and deep 10cm around the trunk. It can also be combined with early winter or early spring planing to pick out its pupa at any time. In addition, the characteristics of false death and landing of the larvae after being frightened can be used to shake the trees and shake down the larvae in the period of larval damage and kill them on the spot.

⑵ drug control: according to the characteristics and harm law of jujube inchworm, drug control can be divided into 2 times. When the juvenile worm is 4-10mm, the drug control can be carried out continuously for 1-3 times, and it is suitable to choose 4000 times of fenvalerate EC or 4000 times of carbaryl wettable powder.