A small hole of about 1.5 cm appeared at the bottom of ash tree trunk. What insects caused this?

I haven't seen the photo before, and it's hard to say what it is. But I guess it's caused by longicorn larvae. There are several kinds of longicorn beetles. But the prevention and treatment methods are similar. Prevention method: 1, drug prevention. Spraying the whole plant with 40% dimethoate 800- 1000 times solution, or injecting chemicals into the trunk wormhole with 40% dimethoate 800 times solution. 2. artificial control. Use Anoplophora longicorn to fake death, or use black light to kill. 3. arrest adults. After the adult emerges. Often eat twig bark to mate around noon on sunny days. In the first half of July, it is sunny, breezy and hot, at noon 1 1 ~ 14, which is the most active period for adults to mate and lay eggs, and the flight is weak, so it can be captured manually. Adults like to move in the sunny place at the top of the crown of Fraxinus mandshurica, citrus, Lagerstroemia indica, Azadirachta indica, jujube and Platanus acerifolia. It is easy to catch in the nursery, but difficult to catch in big trees such as parks and street trees. At the peak of spawning in the middle and late July, you can find the eggs by looking for the carved grooves on the trunk of the tree, and then knock them out. Hook the larva. Once a year in early August, once a year from late September to 65438+1early and middle October,165438+1late October, and the fourth time in late May of the following year. The fourth time is mainly to hook out the mature larvae after wintering. Generally, drug injection is used in February of 1 1 ~ 12 and April to May of the following year. First, remove the sawdust from the insect manure with a knife, then inject 50 times of dichlorvos or trichlorfon into the notch and drain hole with a plastic oil spray pot, inject it from top to bottom, and then seal it with mud. Reasonable thinning of branches can reduce the oviposition rate. Clear and cut down severely damaged ancient trees. Note: Anoplophora glabripennis is most afraid of high temperature. Therefore, reasonable pruning and thinning should be carried out from May to June every year to increase the temperature on the surface and inside of the trunk, destroy its living environment, inhibit its spawning and promote the death of newly hatched larvae.