Bluegrass Billbug (Coleoptera: Curculionidae) Tolerance of Ryegrass Cultivars and Selections1

Abstract

We report for the first time that perennial ryegrass (Lolium perenne L.) cultivars and selections, like those of Kentucky bluegrass (Poa pratensis L.), show differential response to the bluegrass billbug (Sphenophorus parvulus Gyllenhal). The correlation coefficient between injury rating and billbug density in soil and turf grass samples was r = 0.99. Of the 8 ryegrasses, 3 entries, ‘H 5-1352,’ ‘Pennant,’ and ‘Regal’ were found to be minimally damaged (1% to 4%), and the billbug density ranged from 0–0.5/0.09m².