This is a nest of the American pine processionary caterpillar (Tthaumatopoea wilkinsonii) or the European pine processionary caterpillar Thaumetopoea processionea. Whichever one it is, its a serious pests of pine trees in Israel both in forests and in town. At the moment there is no systemic insecticide that can be used to control it so that its control in urban areas is very difficult.

For more information on this insect's close and distant relatives, why not visit my check-list of Israeliinsects?