The hickory bark beetle is reported to be the most serious insect pest of hickory in the United States. Population explosions where thousands of trees were killed have been reported from New York, Pennsylvania, Maryland, Virginia, and recently from Georgia. Hickory bark beetles are distributed throughout the range of their host in eastern United States. All species of hickory are subject to attack, as well as pecan and possibly butternut. Adult beetles emerge in May and June in the southern portion of their range. They feed for a short time by boring into the petioles of leaves and into small twigs of the host. Dying leaves and twigs are the first evidence of attack. After feeding, the beetles fly to the trunk and larger branches of the host and bore into the inner bark to lay their eggs. Short, longitudinal egg galleries are etched into the sapwood and from 20 to 60 eggs deposited in small niches cut on either side of the gallery. As the larvae develop, their galleries radiate out from the egg gallery. Two generations per year have been reported from northern Mississippi. The beetle overwinters in the larval stage. With the coming of warm weather in the early spring, it changes into the pupal stage, and finally, in May, to an adult.
Hickory bark beetle adult.
Outbreaks of this insect begin in periods of hot, dry weather and subside when rains commence.
Larval galleries of the hickory bark beetle.
SMALLER EUROPEAN ELM BARK BEETLE, Scolytus multistriatus (Marsham)
The smaller European elm bark beetle was first reported in the United States in 1909. Its presence in this country was given significance with the introduction of the Dutch elm disease in 1930. The beetle attacks all native and introduced species of elms and now occurs wherever the hosts are present. The feeding of the adult beetles in the spring is responsible for transmitting the Dutch elm disease from diseased to healthy trees. The Dutch elm disease is now our most important shade tree disease.
Smaller European elm bark beetle adult.