Key Points of Pest and Disease Control Techniques for High-Quality Early-Bearing Walnuts

Pest and Disease Control Strategies for High-Quality Early-Bearing Walnuts

1 Analysis of Diseases and Control Strategies for High-Quality Early-Bearing Walnuts

1.1 Analysis of Control Strategies for Black Spot Disease in Early-Bearing Walnuts

Black spot disease in early-bearing walnuts is mainly caused by fungi. When these fungi invade the walnuts, they cause the walnuts to rot, resulting in the dropping of young walnut fruits. In the control of black spot disease in early-bearing walnuts, the following two technical methods are mainly applied: ① Physical control techniques, which mainly involve removing walnut fruits, branches and leaves that have already been infected with black spot disease to prevent further infection by such fungi. ② Agricultural control techniques: in the early stage before walnut bud break, spray lime sulfur mixture on them, with the number of applications controlled at around 4 times; when the walnuts grow to the leaf expansion stage, use Bordeaux mixture to spray them, thereby achieving the purpose of controlling black spot disease.

1.2 Analysis of Control Strategies for Rot Disease in Early-Bearing Walnuts

As one of the more common diseases of walnuts, rot disease is mainly caused by fungal infection, and its peak incidence period is mainly around May each year. Once a walnut is infected with rot disease, foam-like liquid will flow out from its branches and trunk. If the disease is severe, this liquid will appear black, ultimately causing the walnut tree to die. In the control of rot disease in walnut trees, there are mainly the following three control strategies: ① Agricultural control techniques, in which managers of walnut orchards prune out diseased and old, weak branches according to the actual situation of the walnut disease incidence. ② Physical techniques: once a walnut tree is found to be infected with rot disease, immediately remove the diseased parts. ③ Pesticide control techniques: first scrape out the diseased parts, then spray 50% thiophanate-methyl wettable powder at 30-40 times dilution on the scraped areas. At the same time, whitewashing can also be used for control, for example, by mixing clear water, vegetable oil, salt, sulfur powder and quicklime in a ratio of 20:0.1:1:1:10, and then applying the mixture to the main trunk of the walnut.

1.3 Analysis of Control Strategies for Anthracnose in Early-Bearing Walnuts

If walnuts are infected with anthracnose, fruit drop or shriveling of walnut fruits will occur, and at the same time a large number of small black spots will appear on the outer surface of the walnuts. Especially when the growing environment is relatively humid, these external black spots will slowly turn pink. To effectively control anthracnose in walnuts, the main approach is to improve the walnut's own disease resistance so that it can effectively resist anthracnose, for example, by increasing the application of organic fertilizer. If the walnuts have already been infected with anthracnose, pesticides can be used for control, and 95% fosetyl-aluminum at 800 times dilution can be sprayed on the affected areas, thereby achieving the effect of treating the disease.

2 Analysis of Insect Pests and Control Strategies for High-Quality Early-Bearing Walnuts

2.1 Analysis of Control Strategies for the Walnut Shoot Borer in Early-Bearing Walnuts

Among the insect pests of early-market walnuts, the walnut shoot borer is a relatively serious pest. Especially in relatively humid growing environments, walnut shoot borers will reproduce in large numbers. They usually reproduce and lay eggs at night, and during the day they rest behind the walnut leaves. When walnut shoot borers grow to the larval stage, they enter the walnut fruits to cause damage. There are mainly the following two control measures for walnut shoot borers: ① Chemical control techniques: use 40% phoxim at 200 times dilution or 40% chlorpyrifos at 200 times dilution and spray on the walnut trunks to remove overwintering insects on the trunks. At the same time, during the adult stage, pesticides such as Juesha Juzhie, Qingchu Heihetao and Chong'echujin can be sprayed for control, and spraying can be carried out multiple times according to the actual situation, thereby effectively controlling the damage of walnut shoot borers; ② Manual control techniques: a. Overwintering insects on the walnuts should be cleaned up to prevent them from reproducing in spring; b. Remove walnuts that have already been damaged [Jishan Huayao], and the insect sources can be eliminated by deep burial or burning.

to eliminate the insect sources.

2.2 Analysis of Control Strategies for Walnut Scarabs and White Peach Scale

① The scarab is an omnivorous pest, usually becoming adult and laying eggs in June. Control of scarabs can be carried out during this period. The first method is to knock the scarabs off by striking the walnut trunks, then collect them centrally and dispose of them. If there are too many scarabs on the walnut trees, chemical control can be used, and 50% phoxim emulsifiable concentrate at 800-1000 times dilution can be sprayed on the trunks, branches and leaves, thereby achieving the purpose of controlling scarabs. ② White peach scale is a pest that sucks nutrients from the trunk. When there are relatively many white peach scales on a walnut tree, it can cause the walnut tree to die. Generally, the following methods are mainly used to control white peach scale: a. Increase the amount of phosphorus and potassium fertilizer applied, promptly clean up dead and diseased branches and leaves, and carry out reasonable pruning, etc. b. If the pest infestation is relatively serious, manual removal of insect eggs can be used for control. c. Use pesticides such as Jieshate at 800-1000 times dilution sprayed on walnut branches and leaves for control.