Adult beetles drill feeding galleries through the buds and destroy them, compromising fruit formation. The galleries in trunks or branches also disrupt the normal circulation of sap, hindering water and nutrient from reaching branches above. Adults are dark-brown, about 2.5-3.5 mm in length and with dark wing covers punctuated with stiff hairs. The larva is mostly white with a brown head. It is a profiteering insect that mainly attacks weakened trees and thus desiccated broken branches. During the cold season, as long as the temperature is below +5°C the bark beetles stop feeding. In the right conditions, it can be very harmful to pistachio trees.
The damage is caused by the beetle Chaetoptelius vestitus, a member of the Scolytidae family. Adults emerge in April-May when temperatures rise above 25 °C. Females fly to young twigs of healthy trees to bore short tunnels into the terminal or floral buds, thereby destroying them. They later also start to feed on young shoots and twigs, which wither very quickly as the consequence of the damage. During summer and winter the beetles hibernate within the pistachio twigs. At the end of the winter, females look for weakened or broken branches wherein they excavate reproductive galleries and lay approximately 80-85 eggs.
To control bark beetles, it is important to have vigorous, healthy trees and to make sure to apply a series of preventive measures together with neighboring farms. Some parasitoids wasps attack this beetle, as do several predatory beetles and mites. Their overall controlling effects has been estimated to be around 10% of the pest population.
Always consider an approach that combines preventative measures with biological treatments if available. This pest is inaccessible to a simple chemical control even combined with mineral oils that facilitate the penetration of insecticides. Therefore, preventive measures are essential to avoid its spread. They should be applied by all growers in a region so that the insects cannot migrate from affected orchards to healthy ones. The bark beetle attacks mainly weakened trees, so it is necessary to keep the trees healthy (fertilization, irrigation, pruning, pest and disease control).