New UT Beetle-rearing Facility Operating
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Currently, the most promising option for controlling hemlock woolly adelgids (HWA) at a forest-level is a tiny non-native beetle, the Pseudoscymnus tsugae (Pt beetle). Having co-evolved with the hemlock woolly adelgid in Asia, the Pt beetle preys exclusively upon it. A new Pt beetle-rearing laboratory has been established at the University of Tennessee Institute of Agriculture.
Rearing Pt beetles requires a "starter" population of Pt beetles, an ample supply of HWA to feed the beetles, and a Pt beetle-growing room where the temperature can be maintained at 78°F and the relative humidity at 45 %. It also requires a small, trained staff to care for the beetles and the various life-stages of their offspring.
 Key to rearing Pt beetles is an abundant supply of food-the hemlock woolly adelgid. Adelgid-infested limbs are harvested from hemlocks in the Great Smoky Mountains National Park and transported to the UT lab. Limbs are kept hydrated and lit in a temperature- and humidity-controlled room.
 The Pt beetle-rearing process begins with a starter population of adult beetles. Lab technicians sort this population under microscopes by sex. From this sorted population, technicians gather ten female Pt beetles and five male Pt beetles. These beetles are placed inside a growing chamber-it is called an oviposition jar but looks like an overgrown mayonnaise jar-that has been prepared with a hemlock woolly adelgid-infested limb in a watering tube.
 The beetles are kept in the chamber for one week, by which time the females have laid eggs. A 1.5 x 1.5 inch piece of cheesecloth laid on the hemlock branch is a preferred place for egg-laying, and about 50% of the eggs in the chamber will be located on it. This cheesecloth makes the task of recovering the eggs a bit easier for lab technicians.
The Pt beetle eggs are placed in a larger container, prepared with infested hemlock limbs. In this container, larvae emerge from the eggs and feed on the adelgids. The larvae become adults, which continue to feed on the adelgids, and the cycle of reproduction begins again.
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