Ventura and LA County Bad Beetle Watch

Thank you for joining our volunteer community science team to learn more about the Polyphagous and Kuroshio Shot Hole Borer beetles (collectively known as Invasive Shot Hole Borers, ISHB, or BAD BEETLES) and other emerging tree pests!

ISHB are invasive wood boring beetles that attack numerous native and non-native trees in Southern California, including commercial avocado groves. While these beetles mechanically damage trees by boring galleries (caves) into trunks and branches, both beetles also carry a fungal disease called Fusarium Dieback. This fungus is “farmed” by the beetles as food and supports their reproduction. Trees that become infected with this fungal disease are prone to branch dieback, canopy loss, and mortality. Mortality can occur quickly within 1-5 years. A conservative estimated rate of spread is 1.5 to 2 miles a year. This is, however, drastically increased by humans as we transport infected wood. In Southern California, the drought has already weakened many trees and now they must fight infestations as well! Your participation is needed to detect early infestations in Ventura and Los Angeles County. This knowledge will assist us, and many other conservation agencies, plan for management. While this beetle/disease complex can affect hundreds of tree species, this survey will focus primarily on five species: one native box elder, two native willows and two sycamores (one native and one non-native). These species are a few of many known reproductive hosts (these are trees where all life stages of the beetle have been found. For a complete list, visit www.pshb.org). The box elder (Acer negundo) ,arroyo willow (Salix lasiolepis) and red willow (Salix laevigata) are early detection systems, and are often the first species to show infestation and are found in the sensitive riparian zone. The non-native London plane sycamore (Platanus x acerifolia) is commonly found planted in wildland-urban and urban areas. The native California or western sycamore (Platanus racemosa) is commonly found in wildlands (usually near a creek, or riparian, environment) and planted in urban areas. All are highly susceptible to pests, and both the trees and the pest damage are easy to see. less ↑