The adults lay a few eggs per day in the alfalfa stems and petioles, which hatch about 9 days later. They resemble adults, except they are wingless and are often found on the underside of the leaves. The generation interval is short, with about 25 days from egg laying to the adult stage. This gives the leafhopper the ability to have an explosive population growth. PLH are killed by frost in the fall.
Leafhoppers feed by inserting a stylet into a leaf midrib and sucking sap juices from the plant.
They inject saliva containing a toxin into the plants as they feed. This causes abnormal cell growth and interferes with transportation of fluids and nutrients in the leaves. It also causes reduced stem elongation, reduced root development, leaf cupping and stunting. Decreased stand vigour results in slow regrowth following cutting and increased winterkill. New seedings are very susceptible.