What are the common pests and diseases of Populus davidiana? What is the manifestation of injury? How to prevent it?

The common pests and diseases of Populus davidiana by green farmers in Jiangxi province and their control techniques are introduced as follows:

I. Apriona germari

1, hazard: adults eat bark and leaves of twigs; Larvae feed downward under the epidermis and woody parts of branches, and there is no dung in the tunnel. At a certain distance, the larvae feed out through the 1 vent, discharging a lot of dung scraps, making the tree weak and even dead.

2. Prevention and control measures: First, artificial killing. Using the characteristics of weak flying ability and suspended animation, adults can be captured artificially. According to the habit of biting the groove to lay eggs, find the spawning groove and kill the eggs with hard objects. Check the trunk regularly, and when fresh dung scraps are found, gently open the cortex with a knife, and the newly hatched larvae can be executed. Cut off damaged branches in time, cut down dead or broken trees, and renew aging trees so that they have no suitable spawning grounds. Secondly, according to the phototaxis of longicorn adults, black lights, frequency-vibrating insecticidal lights and Moraceae plants can be set up to trap and kill adults. Whitening the trunk in winter can also reduce the occurrence of Apriona germari. The third is drug injection prevention. 50 ~ 300 times of dichlorvos stock solution is mixed with diesel oil according to the ratio of 1∶20, and then injected into fresh drainage holes, or cotton is dipped into the depths of wormholes to kill beetle larvae; Or insert the drug-containing end of the poison stick into the wormhole, break the poison stick, and block other cavities with wet soil.

Second, Yang Fan Ship Moth

1, hazard: larval damage between spring and summer. Larvae eat the leaves of Populus davidiana, and when it is serious, it eats them up, which affects the growth of trees. 1 ~ 2 larvae only eat the lower epidermis of leaves, leaving only the upper epidermis and veins; After 2 years old, silking leaves will form large insect bracts, which will hide in them during the day and feed at night. After the 3rd instar, the whole leaf can be eaten up, leaving only the petiole.

2. Prevention and control methods: First, crush the larvae with hands, or remove the insect leaf buds and burn them. The second is to collect fallen leaves and weeds under damaged plants in winter or early spring, accumulate fertilizer or burn them. Searching and killing overwintering pupae in cracks in bark, tree holes and buildings. Thirdly, the larvae can be sprayed with 20% imidacloprid 800 ~ 1 000 times, or sprayed with Bt above 1 100 million spores/ml. Fourthly, in the adult stage, dichlorvos can be used for large-scale fumigation and killing in woodland, and can also be used for light trapping and killing.

Third, the poplar winged moth.

1, harm: it is a branch pest of poplar seedlings. After the terminal bud was killed, it withered and drooped, inhibiting the growth of the terminal bud. At the beginning of the invasion, pests first feed around the trunk between the essence and phloem of the tree, forming nodular galls.

2. Prevention and control methods: First, pay attention to strict inspection in spring, cut off the seedlings with galls and treat them centrally. In autumn, the trunk and lateral branches of 1 ~ 2-year-old Populus davidiana were inspected, and the galls were cut off and burned centrally. Second, from early May to late July, the ratio of 50% cartap and 50% phoxim to water is 1∶ 1, which is washed with wool and coated on wormholes or galls to form an annular medicine belt with a width of 8 ~ 10 cm. Brush the wormhole with 40% omethoate, 50% cartap and 60% Ma Di mixture 30 ~ 40 times in July ~ August, and the dosage is appropriate to discharge bubbles.