The Oak Processionary Moth (Thaumetopoea processionea) is a notorious moth that is a serious pest of oak trees. In caterpillar form, this insect also presents a human health problem. Its irritating hairs contain poisonous setae which can cause skin irritations and exacerbate breathing problems. The backs of older caterpillars are covered with as many as 63,000 pointed defensive bristles.
Oak Processionary Moths are widely distributed in many parts of Northern and Southern Europe. The wingspan of an adult moth is between 25 and 35mm. Their pattern of tan, brown and white make the adults difficult to see against oak bark.
Infestations were first found in several locations in London in 2006 and they are posing an increasing threat to humans as their range extends.
Control of the problem is best achieved at the early larval stage, by applying a contact treatment. However, several treatments may have to be applied to achieve complete control. In advanced stages of mass nesting, physical removal of the nests may be required to achieve suppression of the pest. Incineration of nests is usually undertaken to ensure eradication and to control the possible spread. At no point should the caterpillars be handled; an expert should be contacted for assistance.
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