Abstract
Effects of temperature and resin on hatch of mountain pine beetle eggs were investigated. Per cent hatch was related to total degree-hours above 40°F, the average being 5113 for 50% hatch under field conditions. Average supercooling point was 1.3°F. Higher temperatures in the freezing range were lethal with long exposure. Atmosphere saturated with volatiles from liquid resin had very little effect on egg hatch, but direct contact with liquid resin greatly reduced egg hatch.