Grafting prevention and control of chestnuts

Cross-winged moth is a devastating pest of grafted chestnut production. With the continuous expansion of the planting area of ​​chestnut grafted, the degree of damage is also increasing, which not only affects the output of chestnut, but also seriously dampens the enthusiasm of farmers to develop the chestnut industry.

1. The symptoms of damage through the wing moth. The larvae are usually strung between the phloem and xylem of the stem of the trunk of the living tree and cause irregular tunnels. Brown worms are piled in the tunnel and at the marrying junction. The epidermis of the affected plant swelled up, the cortex was cracked, and the callus was heavily foraged. After the winter, the grafting tree failed to pull new shoots and resulted in graft failure. If the grafting site is low, the whole plant will die.

2, living habits. In the Dandong region, one-year-old nymphs were breeding for 1 generation. The 2nd instar larvae passed the winter under the victim's skin. From late April to early May, they began to feed. In late May to late June, they were the larvae. After the larvae are mature, they place a round feathering hole with a diameter of 5-6 mm into the skin of the trunk, and then the undergrowth holes are fused with wood chips and feces. According to different parts of the larvae damage, there are differences in the time of phlegm-removal. Generally, the sun-face is about half a month earlier than the shade surface, and the middle and lower parts of the trunk are about half a month earlier than the upper part. Larval larval stage in the middle and late July, 20-25 days of the flood season. In mid-August, adult ecloses began to emerge, and then eggs were laid on rough surfaces of trunks, wounds, and fistulas. Spawning period in late August, egg spawning, egg period of about 10 days, from late August to mid-October for the larvae incubation period.

3, control methods.

(1) Agricultural control: During the larval incubation period, the rough skin below the interface of the ageing tree is cut off with a knife, burned in a concentrated manner, and the larvae and eggs can be eliminated, and the insecticide is sprayed again after scraping the skin. When adult eclosion occurs, black light traps can be used. In addition, the management of chestnut trees is strengthened and the tree vigor is increased to prevent the chestnut trees from being wounded. To improve the grafting method, the grafting interface is not “pressing the lid.” After the plastic strips are wrapped around, they are directly bagged. When the buds grow to 3-5 cm, the bags are picked and the grafting interface is kept clean, avoiding dark and damp, so as to reduce the damage.

(2) Chemical control: During the period from late May to late June, when grafted branches grow to 30-40 cm in length, it is a time when the larvae of the wing-winged moth endangered, and the main focus is on spraying the joints and trunks. 20% of the commonly used agents are fenvalerate. Emulsifiable oil 1000 times, 30% peach Xiaoling EC 1500 times, 2.5% deltamethrin EC 1500 times. It can be controlled at any time, and after the healing of the marrying interface within 1-2 years, the degree of harm will be significantly reduced and it will no longer pose a hazard to grafted chestnut trees.

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