It is a species which was reported in Europe in broad-leaved trees, but also in fruit tree orchards. It is found both in plain and mountain areas.
Butterflies are about 25 mm long, their body is covered by white small hairs; the head comprises 6 blue spots distributed on two longitudinal lines, and the abdomen presents blue transversal stripes.
Male wingspan is 35-50 mm, and female wingspan is 50-70 mm. Their wings are white, the forewings are bigger than the back wings and they comprise numerous dark blue or black spots, which are more diffuse on the back wings.
The eggs are ovoid, about 1 mm long, yellowish-brown colored. The larva is pink, then it gets blotted yellow and can reach up to 60 mm in length, and the head and thoracic plate are black.
It comprises black wart sats on segments 2 and 11, and one sat can be found on each wart. The chrysalis is 40 mm long, yellowish brown, and in the frontal area it presents a formation which resembles a thick horn, curved towards the back. It comprises transversal arrays of bristles.
Biology and ecology:
In our regions, it has a cycle of 2 years, and the larva overwinters twice. Adults fly from June to beginning of August and live for 8-10 days, mating overnight.
The female lays up to 1000 eggs, in the bark cracks, nearby shoots, on the bark of young stems, on leaves stalks. Incubation takes 1-3 weeks. Young larvae attack the organs of the young trees first.
Neonatal larvae first weave a silky nest, where they first remain grouped, then they chafe galleries in shoots, in leaves stalks and around young stems and, after the second overwintering, caterpillars chafe thicker branches, then the stem, which form galleries reaching 50-60 cm in length. The larvae eliminate sawdust excrements from galleries, which are orange or red colored.
Caterpillars hibernate inside closed galleries, then they resume their activity in spring. During the spring of the third year, the larvae feed for a few weeks, after which they chafe an orifice on the outside, where they form a silky cocoon, where they turn into a pupa, where adults form from.
Attacked plants and damage:
The pest attacks different forest species (they prefer ash primarily, which led to ash withering in the plain area), as well as ornamental plants, but also fruit trees in orchards.
First age caterpillars chafe leaves stalk and young sprouts, while mature larvae dig galleries in wood, in thinner branches in the central area. Sawdust, excrements and thick liquid are eliminated at the surface of the attacked branch, and sawdust gathers at the orifice. The attacked trees have debility symptoms, and pierced branched break.
Prevention and control
If the attack and damage are discovered in a timely manner, the attacked vegetal part needs to be cut and burned. If the attack is advanced, no chemical control is recommended. No special control methods need to be applied, and in exceptional cases, pesticides can be injected in the galleries dug by the larvae. During the flight period, chemical treatments with Decis Mega, Karate Zeon or Faster will be applied.