Derobrachus hovorei

Derobrachus hovorei is a species of beetle in the family Cerambycidae,[1][2] known variously as the palo verde beetle, palo verde root borer, or palo verde borer beetle. For over 100 years, this species was confused with the related species Derobrachus geminatus, and only recognized and given its own name by Santos-Silva in 2007; essentially all literature prior to 2007 therefore incorrectly uses the name geminatus for this species.[3] It is a longhorn beetle native to the American Southwest and northern Mexico which derives its common name from the palo verde tree, and it is one of the largest beetles in North America, reaching up to three and a half inches in length. Adults are black or brown in color, have long antennae, and spines on the thorax. They have wings and can fly, albeit awkwardly at times. Mature beetles emerge in the summer to mate. Adults do not eat, and rely solely on their energy reserves until they die in about one month. While not harmful to humans, they can bite in self-defense.[4][5][6]

Derobrachus hovorei hatches from eggs into grubs, which live underground for as many as three years; as a result, the huge grubs can be uncovered by gardeners doing routine yard maintenance, especially in flower beds surrounding lawns which contain susceptible trees. The larvae are cream colored to pale green, typically with a brown head, and feed on the roots of trees, causing branch dieback. In the wild the most commonly affected tree is the palo verde, although wild specimens of other Parkinsonia species (P. florida, P. microphylla and P. sonorae among the most common) are attacked as well. In urban areas (such as parks, college campuses, cemeteries and the like) where species of Parkinsonia are not often found, D. hovorei can feed on the roots of a variety of trees, including the Siberian elm, white and fruitless mulberry, various cottonwoods and, in the warmest desert areas, citrus.

Larvae can cause significant mechanical damage to the roots of individual trees. Unfortunately due to its subterranean habit, infestation by D. hovorei may not be detected until tree mortality is unavoidable.

The Palo Verde worm is also known to eat through polyethylene gas lines creating gas leaks .