Specialists of the State Specialized Forest Protection Enterprise "Kharkivlisozakhyst" have detected an outbreak of mass reproduction of Lithosia quadra in deciduous stands of Kharkiv region. This species of lichen moth is distributed throughout Europe and Northern Asia east to Japan. It occurs in deciduous forests and fruit plantations, less often in open areas.

Lithosia quadra is a representative of the tribe of moths of the subfamily Arctiidae (Erebidae). The wingspan is 35-55 mm. Males are smaller than females. In adults, there is a clear sexual dimorphism. Males have gray wings with yellow veins and a blue-black stripe on the front part of the outer edge of the forewing. Females have yellow wings with two blue-black dots.

The caterpillar is gray-brown, with thin longitudinal lines, on the back in front, in the center and behind there is one transverse black spot, and under the back there are longitudinal rows of small reddish-yellow warts. The butterfly flies from June to September depending on the location. In the southern part of the range, there is occasionally a second generation.

The larvae feed on lichens growing on trees, especially on oaks, walls and stones. When the species becomes excessive and there is a food shortage, the larvae may eat leaves. It is a rare species, in some countries it is listed in the Red Book.

The outbreak was detected during routine forest monitoring in several districts of Kharkiv region. Specialists note that while this species is not typically considered a serious forest pest, the current population density is unusually high and requires monitoring. The caterpillars have been observed feeding not only on lichens but also on leaves of young oak trees when their preferred food source becomes scarce.

Forest protection services are continuing to monitor the situation and assess potential impacts on forest health. Additional surveys will be conducted to determine the extent of the outbreak and whether any control measures will be necessary to protect valuable deciduous stands in the region.