Diapause in the Sugarcane Borer, Diatraea saccharalis1

Abstract

Studies of diapause in larvae of the sugarcane borer, Diatraca saccharalis (F.), were conduced by periodically collecting mature or nearly mature larvae from a sugarcane field near Port Allen, Louisiana from July 22, 1959 until March 22, 1960. These larvae were reared on pieces of fresh corn stems in a dark cabinet at II constant temperature of 80° F. Those living longer than 19 days in the laboratory before pupation or death were considered in diapause. This arbitrary period of 19 days was the upper 9.5% fiducial limit for the time required for pupation by fourth instars larvae reared from eggs in the laboratory at 80° F. It was concluded that a facultative diapause is probably present among full grown sugarcane borer larvae in Louisiana sugarcane fields during the fall months of each year. diapause larvae were most abundant in a field in October, November and December, 1959. Diapause development apparently required about 3 months. Larvae in diapause were not completely inactive. Diapause larvae usually did not pupate in the laboratory unless some diapause development had occurred in the field.