Apr 21, · An adult columbine sawfly. Sawflies are a group (sub-order Symphta) of insects in the same order as the bees, ants and wasps (Hymenoptera) that feed on plants. Description: Adult sawflies are wasp-like. Larvae are gray-green with a black head and legs. They have a single, light, longitudinal stripe down the back, two light green stripes and one dark green or black stripe on each side. Larvae are 18–25 mm long when fully grown.
That winding scar is absolutely damage from the first instar stage of European apple sawfly. The orangish sap indicates fruitlet entry which often will be in a second (different) fruitlet if a flower cluster set more than one fruit. Observing that winding scar on abundant fruitlets is how I know to spray Entrust. You can easily tell an adult sawfly from wasps and bees because of their stout bodies without a stinger. They’re actually pretty rare and will hide most of the day, so you’ll likely see more larvae than adults. The female adults lay eggs in “saw” structure, which is where their name comes from.