When we see plant pests here at the Garden, we always try to use biological or least toxic means of control. So, when we came upon these sawflies on one of our small pines in the Gateway Garden, we knew the best control measure would be insecticidal soap. Soap is essentially potassium salts of fatty acids. Soft insect skins cannot tolerate soapy water, so the insects usually die fairly quickly once sprayed.

It’s important to inspect your plants and trees regularly. Pests like sawflies blend in well on the tips of the pine branches, so you may not notice them until you see significant damage to the tips. Sawflies also tend to feed as a group and can therefore do unsightly damage pretty quickly. Sawflies are actually in the insect order Hymenoptera, which includes bees, wasps and ants. They don’t sting, but they can be locally problematic on a number of different pine trees. Late spring is the best time of year to control them - when the larvae are young, soap works really well.

Posted by Cynthia Druckenbrod

Pictured below: European Pine Sawfly