Now is the time to begin watching pine trees for feeding damage by clusters of European pine sawfly larvae. These gray-green larvae with the shiny black beady heads are common on mugo, Scots and red pine, and may be found on other pine species as well (white and Austrian pines are usually only attacked if interplanted with the more susceptible species). The phenological indicator plants and their stage of development that coincide with the onset of European pine sawfly egg hatch and presence of small larvae are:
- Serviceberry in bloom
- Redbud beginning bloom
- Purpleleaf sand cherry in bloom
Sawfly control is not difficult when the larvae are detected early. Mechanical control by pruning cluster-containing twigs from the tree is possible. Vigorous shaking to dislodge the larvae and raking them up from the ground for discarding is also a possibility. Spot-spray treatment of infested trees can be done for control. Sevin, Orthene and horticultural oil (at the "summer rate") are suggested choices. Read and follow label directions.
This article originally appeared in the April 29, 1992 issue, p. 66.