|Mint Root Borer|
|Biology of Pyrausta
fumalis¹ on Peppermint in Oregon²
RALPH E. BERRY
Department of Entomology, Oregon State University, Corvallis 97331
© 1974 Entomological Society of America
Ann. Entomol. Soc. Amer. 67:580-582 (1974)
Pyrausta fumalis (Guenee) is a newly discovered pest of peppermint in Oregon. P. fumalis is univoltine and overwinters in the soil as a diapausing prepupa in a hibernaculum. Pupation occurs in late spring and adults begin emerging in early June and continue through late August. Peak emergence occurs during a 3-4 week period from late June to late July. In the laboratory, eggs are deposited in masses along leaf veins on the upper and lower surfaces of peppermint leaves. Eggs hatch in 9-10 days and larvae feed on the upper surface of the foliage for 4-5 days before dropping to the soil surface to enter rhizomes. Larvae bore into and feed within rhizomes for 70-80 days and cause serious injury during late August and September. Larvae complete development and construct overwintering hibernacula during late September and October.