Trees in Istanbul are under threat from insects previously unseen in the country's most populated city.

After sightings of two different species of insects devouring trees in the Fatih and Zeytinburnu districts of the city's European side, a new species harming trees was discovered in Cihangir, a bohemian quarter in the Beyoğlu district.

Municipality workers sprayed trees in Cihangir yesterday with pesticide against a poisonous subspecies of caterpillar. The caterpillars were first detected two weeks ago and are only harmful to trees and do not pose a threat to public health, authorities said. Though the source of the insect epidemic is not known, it is thought that they found their way into Cihangir through imported trees dotting the neighborhood or soil used in gardens brought from other places. Apart from spraying pesticide, workers chopped off the limbs of trees withered by the insects. Numan Akol, head of veterinary services for the Beyoğlu municipality, said the natural predators of caterpillars were unavailable as birds and other animals have stopped eating those insects. Akol said they started applying pesticide last week to some areas in Cihangir but caterpillars spread all over the neighborhood.

Similar cases of insect invasion were reported in the city's Zeytinburnu district last year and Fatih this year. The citrus long-horned beetle, native to Asian countries, was also discovered in two districts, devastating trees.