Pistachio twig borer / Kermania pistacchiella

Pistachio twig borer is the most widely distributed pest species with the highest infestation rate in pistachio fields.

Pistachio moth, eats and damages wood. The larvae of this pest enter the wood immediately after hatching and begin to damage them. Due to the creation of larval channels, the growth of branches slows down and affects the next year's harvest.

The adult moth appears in late March-early April, lays its eggs in flower and fruit clusters, as well as on new shoots and petioles during high pest populations. The newly hatched larvae directly penetrate into the cluster tissues from which they bore into the rachis fruit cluster. Larvae tunneled in the pedicel of fruit cluster and branches and began to feed. There are four larval instars in pistachio woodborer life cycle. 

The first larvae of the first instar penetrate the tissue of clusters and branches in mid-may. At the end of June, the larvae are one or two development stage old. The larvae feed from the second instar until the beginning of July. The larvae period is three generation old from the end of July to the beginning of December. All larvae from the third to the fourth instar are processed in mid-December.

The larvae are very small and white during hatching, they remain white in life later, and only the jaws turn brown. These larvae are legless until the third instar. Larvae of the fourth generation the body color of the larvae becomes blackish-gray, and three pairs of thoracic legs and five pairs of abdominal legs appear. It seems that the reason for this type of metamorphosis is that in the first or third instar, the larvae feed inside the wood and do not need legs, and in the last instar (fourth instar), the larvae must leave the branch and find a suitable place to pupate.

The width of full males and females with open wings is 11-13 mm. The forewings are dark grey to black, with a large yellow triangular spot in the middle. The dorsal wings are light yellow. The top of the wings is strikingly dark.

This pest overwinters as an adult (fourth) larva in infected branches. The larvae of the last instar come out of these branches, making holes, and after a few hours of movement turn. Most of the larvae choose the branches to pupate.

After about 25-30 days, adult insects appear. After mating, adult males and females lay eggs separately on the tops of young shoots of one year. According to research, larvae do not enter the core or wood tissue immediately after hatching, but first move in a spiral in the bark, outside the phloem vessels, and then enter the Central and inner parts.

Perhaps the reason for this behavior of the larvae is the softness of the tissue, as well as the high level of juice.

Mass trapping is gaining importance as one of the only alternative management methods for bringing the pest under control. Sex pheromone traps have become an important component for monitoring and mass trapping of pest species in agricultural area.

Proper use of Pheromone Traps:

The pheromone trap is designed to monitor and reduce pest numbers. In order to determine the population density of pest insects and to identify pest outbreaks (monitoring), it is recommended to use 1 trap per 1 ha.

The trap should be placed in the crown of the tree at a height of 1.5-2 m.  Prior to the first flight of the butterflies, the traps must be checked on a daily basis, and after the first butterflies have been captured, the traps must be checked every 5-7 days. Pheromone dispensers and adhesive tapes can be replaced as needed. Protective measures are based on the results of the monitoring of population density of pest insects.

Trap placement:

For mass capture and sterilization of males, it is recommended to have more than 20 traps per hectare. In case of a large number of pest insects use 30 traps per 1 ha.