Plants can predict sawfly emergence Plants are good indicators of when spring has arrived.
Lawns turn green, then are soon dotted with yellow dandelion blossoms. Panicle emergence in wild grasses also are good indicators of insect activity. For several years, I have observed that sawfly wasps emerge when smooth bromegrass heads appear. Cheatgrass is the earliest andis followed by timothy and Kentucky bluegrass. Smooth bromegrass is a little later, and quackgrass is later still.