The European pine sawfly is a pest of Japanese black and red, mugo, and scotch pines. It is dark green with a black head. They exist in colonies of 10-30 individuals that feed close together and move very little. Since they align themselves along the needles, it is difficult to see them. This sawfly feeds on last years growth and they can defoliate needles rapidly as they mature.
Hosts look sickly and growth is reduced.
Control with a host of materials such as sevin, diazinon, malathion or several restricted use compounds. Spot spraying works if you only have a few trees, but scout carefully to catch each colony. Some protection can be achieved with fungicide applications now. For new plantings select scab resistant cultivars. Botrytis has been very common this spring especially in beds that have been in tulips for a long time.