Gage County
1115 West Scott St.
Beatrice NE 68310
Phone: (402) 223-1384
FAX: (402) 223-1370

European Pine Sawfly

Distribution: This pest was imported form Europe and now can be found from southwestern Ontario through New England and west to Nebraska.

Hosts: Prefers Scotch, red, jack, Japanese red, table, mountain and mugho pines. Will feed on white, Austrian, Ponderosa, shortleaf and pitch pines if these are intermixed with the preferred hosts.

Damage: The young larvae can only eat the needle surface which causes the needles to turn straw colored and wilt. As the larvae grow, they remain together and feed from the tip of a needle to the base. The larvae feed on older foliage and move from branch to branch as they strip the needles. Trees which are entirely defoliated are severely stunted but since the new growth is rarely attacked, the trees will survive. Larvae will often migrate to new trees if the needles on their current host have been devoured.

Description and Life Cycle: Usually only one generation occurs and the winter is spent as an egg inserted into slits along the edge of needles. The eggs hatch in April through mid-May and the larvae feed until mid-July. The caterpillar-like

larvae are grayish-green and have a light stripe down the back, and a light stripe along each side followed by a dark green stripe. Full grown larvae are about one inch long. The larvae feed in groups or colonies, often with three or four feeding together on a single needle. Disturbed larvae raise their heads and tails in a threatening manner. Mature larvae drop to the ground and spin tough, brown cocoons in the doff. Some larvae may pupate on the tree. The adults emerge in late August through September to mate and lay eggs. The female is a reddish-orange color and the male is black with feathery antennae. Both look like robust, slow flying bees. Each female lays six to eight eggs in a single needle and 10 to 12 needles are used.

Control Hints: Best control is obtained when the larvae are still small, so look for the straw-like needles left behind by the young larvae. Inspections should be made in April and May.

• Option 1: Biological Control - Parasites and Predators - Several parasites have been introduced for control of this pest and native birds feed on the larvae. Rodents often eat the pupae in the soil. These agents are usually not adequate.
• Option 2: Cultural Control - Pruning of Colonies - Since the larvae congregate together, they are easily removed by clipping out the infested branches and crushed. This is adequate on small trees and if the colonies are few in number.
• Option 3: Chemical Control - Spot Insecticide Sprays - Many home-owners and commercial growers keep an aerosol insecticide container or a hand pump sprayer handy for quick spraying of detected colonies in the spring. This is usually adequate for most operations.

European pine sawfly can be controlled with a number of products that contain "natural" insecticidal materials. Azadirachtin works as an insect growth regulator. Horticultural oils and horticultural soaps effectively control the soft-bodied sawfly larvae. But with oils and soaps, what you spray is what you get. Once dried, oils and soaps do not provide residual control. So if initial spray treatment coverage was not thorough, an additional treatment might be necessary to "clean up" larvae that were untouched and have continued feeding.

Insecticides with the active ingredients acephate, malathion, carbaryl, esfenvalerate, rotenone and pyrethrin have longer residual properties, providing some extended control. A possible drawback to these materials is that they are wide spectrum, meaning they will kill not only the targeted pests, but also non-target organisms including beneficial predator and parasite insect species.

Credit & Thanks given to the following resources:
Ohio State University Extension Factsheet HYG-2555-95
Insects and Mites Associated With Shade Trees and Woody Ornamentals, pg 39, K-State Research and Extension Pub S-85

to Contact our Staff

Extension is a Division of the Institute of Agriculture and Natural Resources at the University of Nebraska-Lincoln cooperating with the Counties and the United States Department of Agriculture.
UNIVERSITY OF NEBRASKA-LINCOLN EXTENSION educational programs abide with the nondiscrimination policies of the University of Nebraska and United States Department of Agriculture. We assure reasonable accommodation under the Americans with Disabilities Act.