We think of evergreens as sort of indestructible, but there’s a evil presence lurking among the pine needles. The European Sawfly, and frankly they kind of make our skin crawl. They’ve been especially nefarious this season with their pupating bodies falling to the ground near the base of the tree in brown piles of cocoons. The first stage is the larvae striping the needles of mature foliage, leaving only the central core. You may not notice massive damage if it’s just a small infestation as once they’ve eaten their fill (on only the OLD needles) they begin to become their future selves – the european sawfly. Even though they look like little caterpillars, they’re just larvae, so they never really eat that much before transforming into a less damaging pest. Because they’ve already moved out of their larval stage at this point you have missed your window of opportunity for control. But be prepared as they may well return next year. Here are 2 options for control:
Ah yes, the Ol’ pick n’ squish – it works for so many pests. You can wear gloves if you wish, or dislodge larvae from plants by means of a forceful water spray.
Insecticidal Soap / Insecticides
The natural insecticide spinosad will control sawfly larvae. Conventional insecticides such as malathion are also effective. Bt (Bacillus thuringiensis), which is an effective natural control for true caterpillars, is ineffective on sawfly larvae.