On my plum tree I noticed tunnels and in these I noticed a coming and going of red-headed ants that release a lot of sawdust (I guess they dig in the tree), can all this compromise its stability and what to do to eliminate them?
Thank you in advance for your reply
Ants: Answer: ants
the ants, even the red ones, do not feed on wood, but on insects, fruits, crumbs; generally they are not able to dig the wood of the plants, and often it happens to see many ants on a plant because they are feeding on the aphids present on it, or they are exploiting the galleries produced by other insects. So I think ants are not the cause of the tunnels on your bush, or at least, it would be very strange behavior on the part of ants. Insects similar to ants that dig the wood are termites, but it is difficult to confuse the two insects, since the termites have a light colored body, and slightly swollen, while the ants have a dark body, black or brown, and are of dimensions much greater. It may be that the ants on your tree are taking advantage of the tunnels left by a rodilegno as a house. The wood rods are moth larvae, which are able to dig tunnels in the wood. The females of rodilegno deposit their eggs in groups near the base of the stem, or near new shoots or splits or pruning; when the eggs hatch, the larvae penetrate the wood, causing large tunnels, and obviously also damage to the development of the plant. The most common rodilegno in Italy are two: red rodilegno (Cossus cossus) and yellow rodilegno (Zeuzera pyrina); the first tends to penetrate into the wood even large trees, in the stem or branches, where it leaves a striking entrance hole, from which a brown mucilaginous substance emerges, caused by the excrements of the rodilegno mixed with the remains of the gnawing of the wood. The yellow rodilegno instead tends to prefer the young shoots and the twigs. So, if your plant has been attacked by a wood rod, you should see the entry holes, through which you can hit it. The traditional method consists in following the tunnels with a metal wire, in order to kill the larvae at the end of the tunnel. There are also special insecticide products, which are used by syringing them inside the galleries.