Apply control sprays of soap or many ohter insecticides when sawflys are small.
First generation begins.
Nymphs hatch and begin to damage new growth. Forest tent caterpillars are also active. Cool wet weather, newly emerging perennial leaves, and new annual transplants can lead to a slug feast. Flights can be expected mid month and will likely peak late in the month. Information courtesy Whitney Cranshaw, Department of Bioagricultural Sciences and Pest Management, Colorado State University.