By RACHEL LIVINAL

CV Journalism Collaborative

California farms are facing an increase in pests on some of the state’s most vital crops due to climate change – and can expect to face more, according to a recent study by researchers at University of California Merced and Davis.

Researchers say the codling moth, peach twig borer and oriental fruit moth have increased their presence in California largely due to warming temperatures. The insects attack almonds, peaches, and walnuts – all of which are predominantly grown in the Central Valley.

For the study, researchers focused on 20 counties known to grow specialty crops, which includes all counties in the San Joaquin Valley. Specialty crops are defined by the U.S. Department of Agriculture as fruits and vegetables, tree nuts, dried fruits and horticulture.

California holds the largest agricultural economy in the nation, with revenue reaching more than $50 billion. The state is also the largest producer of peaches in the country.

Researchers note that in order to develop, most pests require a certain amount of heat.

But just how exactly climate change affects pests, and, in turn, how it affects crops, has often been a topic of little research, says Tapan Pathak, the UC Cooperative Extension specialist in climate adaptation in agriculture based at UC Merced.

Pathak says more information can help farms be more resilient. The latest research will be used to update the “CalAgroClimate” database which he says “informs farmers on the progress of pests during the season.”

Although experts have recommended treatment to the pests for years, the study reveals the insects are arriving almost a month earlier in the spring than expected, and may cause future economic damage to California if not treated sooner.

Researchers recommend pest traps to be set as early as Feb. 7, as soon as pest activity begins.

Prakash Jha, a UC Agriculture and Natural Resources assistant project scientist at UC Merced says along with the traps, preventative measures like planting pest-resistant crops, sanitizing orchards during the winter, or harvesting early could also help fight back against infestations.

If not treated, researchers estimate up to half a generation of bugs could be produced in the next two decades.

— Rachel Livinal covers higher education for KVPR in Fresno and the Central Valley Journalism Collaborative, a nonprofit newsroom based in Merced.