How to improve the prevention and control effect of hawthorn red spider in apple orchard? Find the cause and take measures

How to improve the prevention and control effect of hawthorn red spider in apple orchard? Find the cause and take measures

Su Guanlai

Hawthorn red spider is one of the main mite pests that harm apples, and adult mites, young mites, and mites swarm on the back of the leaves to suck sap, destroy the leaf tissue, make the leaves lose green, and the damaged parts show pale spots, unable to carry out photosynthesis. When the damage is severe, the leaves are scorched, like being burned by fire, causing early defoliation and weakening of the tree. Due to various reasons, it is difficult to prevent and control the hawthorn red spider in apple orchards and is very easy to become a disaster.

Gansu Zhuanglang has an area of more than 650,000 acres of apples, and has accumulated certain experience in mite pest control in long-term production practice.

1 The cause of the occurrence of hawthorn red spider is serious and difficult to control

1) Fast reproduction. In early April, the hawthorn red spider overwintering female stings, to September produces overwintering adults, can reproduce 6~10 generations in half a year, 10~15 days to reproduce 1 generation, slow to reproduce about 20 days for 1 generation, in the apple flowering period to lay more eggs, 7-8 months to reproduce the fastest, 8-September is the most serious damage period.

2) Spawning is hidden. The eggs of the hawthorn red spider are usually scattered in the cracks of the bark, under the coarse old warped bark, the soil crevices around the root neck, the clods, and the weeds, and the spawning places are scattered and hidden, and some places are difficult to reach with pesticides, producing a large number of "fish that have slipped through the net", which is very easy to "resurge", especially in the continuous high temperature and drought period, it is easy to break out.

3) The phenomenon of overlapping generations is obvious. The overwintering generation of hawthorn red spider female stinging has a lot to do with spring temperature. In spring, when the temperature rises rapidly and the temperature is stable, the stinging lasts for a long time and the sting is uneven, which has an obvious peak period. In recent years, the spring temperature fluctuation is frequent, resulting in the incubation period of the insect before and after, the egg hatching period is first, generally 7~10 days after the flowering of the first generation of eggs hatching period is relatively concentrated, after the field insect state into the chaotic overlapping period, and the generations overlap, increasing the difficulty of prevention and control.

4) Fast propagation. Hawthorn red spider insect is small, and it can float and spread when blown by a breeze, crawling and floating are the main ways of its close transmission, and windy weather in spring is conducive to its spread.

5) Drought can exacerbate the damage. When the weather is dry and the temperature is high, the occurrence of hawthorn red spider is severe. In the orchards of Northwest China, spring drought and drought often occur, resulting in serious damage to the insect.

6) Decentralized prevention and control, weak control. Hawthorn red spider shows a large-scale occurrence trend, once it occurs, only a large range of drugs can control the harm, but the reality is that the orchard is mostly a small-area household business model, and the scope of drug use for a single family is limited, which is difficult to achieve the effect of group prevention and treatment, resulting in no obvious control effect.

7) The number of natural enemies decreases. If there are a large number of predators such as mites, thrips, lacewings, and mite-eating ladybugs in the field, the population of hawthorn spider can be well controlled and the balance of the ecosystem can be maintained. The extensive use of broad-spectrum pesticides not only prevented and controlled apple pests and diseases, but also killed the natural enemies of the insect, resulting in the weakening of natural pest control ability and the rampant hawthorn red spider.

8) Pest mite resistance is enhanced. Long-term and repeated application of the same or the same kind of acaricide to control hawthorn red spider leads to its resistance and affects the control effect. In regional production, the untimely update of control agents is one of the main reasons for the unsatisfactory control effect of hawthorn red spider pesticides.

9) Improper selection of agents. There are many types of acaricides, and different agents need to be used for different insect states to achieve the desired effect. For example, avermectin and alkyne mites have a good control effect on adult mites,, and young mites, but do not kill eggs; tetramitezime kills mite eggs,, and young mites, and has a weak control effect on adult mites; triazole tin can kill young mites,, adult mites and summer eggs, but the control effect on winter eggs is weak. If the insect state in the field is unclear and the drug is not selected properly, it is difficult to achieve the ideal control effect.

10) Influence of arbographic and garden phases. The occurrence of hawthorn red spider is closely related to the tree potential and orchard permeability, generally good ventilation and light transmission, neat and tidy garden, less weeds, small tree age, strong tree strength, hawthorn red spider occurrence is light;

2. Measures to improve the effectiveness of prevention and control

1) Carefully clear the garden and lower the base. The hawthorn red spider has a single overwintering insect state, which is convenient for centralized control, and the combination of autumn induction and spawning and spring killing can be used to greatly reduce the overwintering base and lay a good foundation for the prevention and control throughout the year. Before the female overwintering in autumn, the grass handles and corrugated paper insect traps can be tied to the trunk and main branches to create a suitable wintering place for the females, and the females can be induced to overwinter, and the grass or insect traps can be lifted from December to January of the following year, so as to eliminate a large number of overwintering hawthorn red spider females. In early spring, lay plastic film or woven bags under the tree, scrape off the coarse old warped bark, and use an iron brush to remove the remaining insect body on the tree at any time, eradicate the weeds around the garden, and burn the bark scraped off.

When the temperature rises to 18 °C in early April, spray 5 Baumé stone sulfur mixture on the soil and ridges of the tree body and tree tray to kill the overwintering females and control the number of overwintering females.

2) Do a good job of medication in the critical period. The hawthorn red spider is relatively single after stinging, and the insect body is less resistant and easy to kill. During the high temperature and dry season from late June to early July, the number of field populations increased, and there was a peak of harm, and timely medication should be used to control the harm. These are the two key periods of the year. If the drug is chosen well, the harm can be well controlled.

3) Choose the right agent. In the prevention and control of hawthorn red spider, choose egg, larval mites, nymphaeae, adult mites and acaricides or a compound of two acaricides as much as possible to improve the control effect. Among the many acaricides, alkyne mite, pyridoxin, nisolone, mite death, triazole tin, etc. have a good killing effect on eggs, young mites,, and adult mites, and can control the harm for a long time. Mites threatened + avermectin, tetramitezine + triazoletin, tetramitezine + avermectin, tetramitezine + pyridoxalin, bifenazide + mitezole and other compounds can be used to kill eggs, young mites,, adult mites, long control time, good control effect.

4) Moderate medication. The concentration of acaricide is low, the killing effect is poor, and the concentration is high, and the hawthorn red spider is easy to develop resistance. During the critical period of hawthorn red spider, 3 000 times of 20% mite dead water suspension or 20% sweep mite wettable powder 2 000~3 000 times, 5% Nisolan EC 2 000 times, 57% alkyne mite special EC 2 000~2 500 times, 16% tetramite-pyridoxin 1 000~2 000 times, 28% tetramite-triazole tin suspension 1 500~2 000 times.

5) Grasp the rhythm of medication. The insect state of hawthorn red spider in the field is complex, and the weather conditions have a great impact on its occurrence, and it is difficult to achieve the ideal effect with a spray, so it can be used once at an interval of 7~10 days and 2~3 times continuously according to the occurrence situation and weather conditions.

6) Alternate medications. There are many kinds of anti-mite agents used in production, and attention should be paid to the alternating use of different acaricides, and each acaricide should be used no more than 2 times per growing season to slow down the emergence of hawthorn red spider resistance.

7) Adopt auxiliary measures to improve the prevention effect. The first is to use sunshine tree shapes such as spindle shape and heart shape, and leave appropriate amount of branches to maintain good permeability of the tree body and orchard. The second is to increase fertilizer water and leave fruit in an appropriate amount to maintain the vigor of the tree and improve the resistance of the tree to insect pests. The third is to grow grass in the orchard to improve the ecological environment, create suitable living conditions for predatory mites, lacewings, ladybugs and other natural enemy insects, and enhance the ability of natural pest control; The fourth is the artificial release of predator mites to control mites.