Shot Hole Borers Vanish From Avocado Trees

Taylor HillmanGeneral, Pest Update


Courtesy: UCANR

Researchers are having trouble finding shot hole borers in the original avocado groves that were infested in California. Experts say the once feared pest may leave infested avocados after a certain period of time.

The California avocado industry may have dodged a big bullet. The California Avocado Commission presented at the California Association of Pest Control Advisors’ annual meeting about the concerning shot hole borer beetles that seemed to favor avocado trees, among many other landscape species.

Research Program Director Tim Spann said the beetles have almost disappeared from the original groves that were infested in Southern California. “So we are about 18 months or so away from the first finds in San Diego County in commercial avocado groves. In those trees today, it’s very hard to find the beetle and those trees are doing very well. They’ve come back, are putting on new growth and are looking very healthy with the beetle population way down,” Spann said. “What will be interesting to see is how Ventura County responds. They are just at a year for the first finds there. We are starting to have some trees there that are fully infested and starting to have some dieback so it’ll be interesting to see if in a years time if we see the same thing with the beetle population declining.”

The research isn’t quite sure what is happening and Spann said there could be a number of contributing factors. “We don’t know if there is something out there that has become a predator of this beetle. Is it just that the dynamics of a new invasive species and it’s tried a whole bunch of things when it first came in and avocado trees, although it is a reproductive host, it’s not high on it’s list,” Spann said. “We really don’t know what’s happening but fortunately for us it appears to not be the pest we thought it was going to be in avocados.”