A Destructive Pine Sawfly introduced from Europe; Diprion (Lophhyrus) simile, Hartig.
The larvae of Lophyrus pini[Diprion pini], L., (similis, Hart.), which is one of the most injurious sawflies on European conifers, were found on 27th August 1914 at New Haven, Conn., upon the foliage of pine trees, though the means by which this pest was imported is unknown. The eggs are laid in slits made along one of the ridges at the edge of the needles. The full-grown larvae devour from 6 to 12 needles daily, preferring the old needles. There are two generations each year, the summer cocoon being formed on the trees and the autumn cocoon at their bases. In Europe, the destruction of needles, rubbish, etc., at the foot of the trees in autumn, is recommended. In Connecticut, the larvae have been found on Pinus strobus (white pine), P. laricio var. austriaca (Austrian pine), P.flexilis and P. densifiara. The trees were sprayed with lead arsenate in September.