Scolytid beetles, often called Scolytids belong to the subfamily Scolytinae (Family Curculionidae). They are one of the most damaging insects in the world, placed in wood boring insect group. 

Adult beetles are small (1-10 mm), brown to black in color. The body may be rough, striated or punctuate or very smooth, clothed with bristles, scales or minute hairs. Several species have spines (tubercles) on the back end, which may have different shapes and be convex , blunt, concave or rounded. The antennae are clubbed. The mouthparts have well developed mandibles used for chewing. The abdomen has five visible segments ventrally and is completely covered by the elytra. Larvae are cylindrical, curled, thick-bodied and leg-less, white or cream-colored, with a distinctive head and visible dark-colored mandibles.

Almost all species of Scolytids are borers both in the adult and larval stages. Scolytids will attack and feed on nearly every part of the tree. They breed under bark or inside wood, therefore, making it easy to transport them and spread to the new environments. Scolytids are one of the first insects to attack dying trees, and are especially important as primary and secondary tree killers. With few exceptions the greatest portion of Scolytid beetle life cycle is spent with the host. The only free, away from the host, living period is spent by the adult in selecting and attacking new trees, that are about to die.

Detection is difficult due to their cryptic lifestyle and to the difficulty in effectively monitoring their populations in remote areas. In the absence of effective monitoring, exotic species may persist undetected for many years before discovery at which time the species already may be a problem.

Currently there are more than 50 exotic species of Scolytids recorded in North America Scolytids are most frequently found on pallets and crating that are made from recently cut trees, with bark retained and not treated with chemicals or heat.

Most beetles come either from Asia or Europe. The vast majority of exotic Scolytids have first been detected in areas near ports which indicates the impact that international trade has on the introduction of these species.

Native Scolytids generally attack stressed or weakened trees, which often can be easily prevented by improving tree health. In contrast, most exotic Scolytids frequently will attack healthy trees as well as weakened trees. Many of exotic species of Scolytids are considered economically significant pests because their damage potential is usually unknown. The majority of introduced exotic species of Scolytids are found in warm-humid climates of the Southeast.
 
Life Cycle

All Scolytids have similar life cycles. Most of their life cycle takes place inside of the wood within the galleries, where beetles mate, lay eggs, and young develop. In the case of ambrosia beetles, adult females construct galleries in the sapwood and inoculate the galleries with a fungus that tends to be species specific. The adults and larvae then feed on this fungus. The excavation into the wood and the introduction of pathogens are the main causes of damage to the host. At certain times, adult females will leave the galleries and fly up to 2-3 km in search of a fresh host plant.