Scientific name: Thyrsostomaguerini
Family: Heliodinidae

This is a small, yellowish moth 4-5 mm long with a wingspan of 12-14 mm. When seated, its body forms a characteristic 35^o angle with the sitting surface. It overwinters either as an egg or as larva (6 mm long worm, yellowish with a brown head) near or in the buds located at the tip of shoots. As soon as sprouting begins, worms become active damaging the tips of young shoots and clusters, where they bore tunnels and pupate (either in the tunnels or in cocoons made from plant tissue that larvae fold along the long side and fix also at 35^o angle with the fixing surface.) Adult moths emerge from mid-May to mid-June and lay their eggs on the young pistachios.

First-generation larvae attack young shoots or enter between still-tender pistachio shells and feed on them. In pistachios that are blackened by fungus, the larvae die, but in the non-infected nuts, larvae keep feeding on them and turn into mature insects which again lay eggs on healthy pistachios. Second-generation larvae can no longer invade the pistachios because of the hardened shells. Instead, they feed on the green pistachio hull where they also make cocoons from which they will emerge as new mature moths for three more generations that all feed on the hull.

ORGANIC

Treatment with Bacillus thuringiensis formulations that target Lepidoptera caterpillars.

CHEMICAL

As soon as the nut appears, (from mid-April), spraying with suitable pesticides. Repeat spraying every week for four weeks and until nutshell hardening. For more targeted application, monitoring adult emergence from infected shoots or nuts by enclosing them in fine muslin is recommended.

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Athanasia Chatziperi, Agronomist, Attica Region