Juniper Twig Pruner
Styloxus bicolor (Champlain and Knull)

Hosts:  Juniper and Arizona cypress

Symptoms/Signs:  The juniper twig pruner adult is 7 to 11 mm long and has a reddish-orange head and brownish to black body. Larvae are small, white, and cylindrical, legless grubs.

Biology:  The life cycle may take as long as 2 years to complete. Eggs are laid on branches, often near an intersection of twigs, 0.5 m from the branch tip. Grubs kill twigs by boring through the centers.

Effects:  Juniper twig pruner causes twig dieback on junipers and cypress growing throughout the Southwest.

Similar Insects and Diseases:  Cedar bark beetles and western cedar borer.

References:  9, 42