Michigan State University Extension
Ornamental Plants plus Version 2.0 - 00001122
01/01/98
Aphid will infest branches and suck plant juices. They produce honeydew which may support sooty mold.
European pine shoot moth causes young shoots to fall over. Infested shoots may exude resin. The insects can be found in the shoots during May. Use properly labeled pesticides when caterpillars are moving from overwintering sites to new shoots. This occurs in mid to late April or when needle growth is about half developed. A repeat application in 10 days is needed.
Bark beetles bore into trunks making small holes scattered up and down the trunk. Stressed trees are more susceptible to attack. The holes look like shotholes. Keep trees healthy and use properly labeled pesticides once a month in May or June and July.
Sawfly larvae caterpillars are variously colored but generally feed in groups on the needles. Chemical controls applied when larvae are small are more effective. Some sawfly larvae will flex or rear back in unison when disturbed.
Pine needle miner larvae feed inside needles causing them to turn yellow and dry up.
Pine needle scale is a white, elongated scale found on the needles. Pine tortoise scale is brown and found on twigs. Pine needle scale crawlers are usually active when the lilacs are in full bloom.
Pine spittle bug lives and hides in a foamy mass.
Mites cause older needles to become yellowed or stippled.
Zimmerman pine moth larvae bore into the trunk. The only outward symptoms may be death of parts of the tree or masses of hardened pitch on the branches.
The larvae of pine weevils feed on the sapwood of the leaders. The leader is killed and the shoots replacing it are distorted. First symptoms are pearl white drops of resin on the leaders. The leaders die when the shoot is girdled as adults emerge in August. Prune out and burn infested terminals before July 15.