The broad-necked root borer, Prionus laticollis (Drury), causes economic damage to apple orchards in the eastern United States by boring in the roots of apple trees. The insect has a 3- to 4-year life cycle. Eggs are deposited in the soil or on the soil surface in mid-summer, and larvae tunnel through the bark and may excavate the interior wood of living, weakened, or dead apple tree roots. Larvae leave the roots to pupate in the soil and have been found up to a depth of 84 cm below the soil surface. Prepupae occur in the soil during May and June and pupae in June and July. Adults live approximately 1 week after emergence and mate several times. A tachinid fly, several potential pathogenic microorganisms, larvae biting one another, and freezing temperatures were observed to be mortality factors.