The caterpillars form nose-to-tail processions on the oak trees
Staff at Jersey's schools are being trained to spot caterpillars that can cause severe rashes, to ensure children do not come into contact with them.
The island has had several infestations of the oak processionary moth.
Its caterpillars' hairs are toxic and can lead to painful rashes, eye and ear irritation and breathing difficulties.
Scott Meadows from the Environment Department said school caretakers and grounds staff were looking out for any nests that might be on school grounds.
The oak processionary moth is named after its habit of forming nose-to-tail processions on trees.
It is a major defoliator of oak trees across Europe, feeding on leaves and producing silken nests on the trunk or branches of oak trees.
The adult caterpillars have about 60,000 barbed hair bristles containing a toxin which, if inhaled, can trigger an asthma attack or even anaphylaxis.
The first infestation in Jersey was discovered in 2007 at Five Oaks.
Several people needed hospital treatment last year because of moths' nests in two trees in People's Park. The trees were later felled.