Insects & Diseases

California Oak Moth


The California Oak Moth (Phryganidia californica) is back in town and can be observed fluttering in the evening around many of the City's public oak trees. The moth is common to our area and is a cosmetic pest, meaning the damage caused is not detrimental to the tree.

Urban Forestry staff is currently monitoring our active moth population but not spraying, since our goal for many years has been to reduce pesticide use to control these natural pests and to find a healthy balance between minimizing debris associated with the oak moth while preserving the health of our public street trees. Read more from UC Davis Integrated Management Website.
A moth flying next to a leaf on a tree.

Asian Citrus Psyllid


Learn how you can protect your citrus trees from a plant disease called Huanglongbing (HLB) and the Asian citrus psyllid, a pest that can spread the disease.

In March 2012, Huanglongbing (HLB) – a plant disease considered a death sentence for California citrus – was discovered in Los Angeles, putting homeowners on high alert. While not harmful to humans or pets, once a citrus tree is infected with HLB, there is no cure and it will die. The disease can be spread by a pest called the Asian citrus psyllid, and the pest has been found in and near the city of Ventura. The best way to protect citrus trees from the disease is to control the psyllid population.
A green leaf with small insects on it.
Help protect your backyard citrus trees through these tactics:
  • Inspect citrus trees for signs of the pest and disease each month or whenever watering, spraying, pruning or tending trees.
  • Call the California Department of Food & Agriculture hotline at 1-800-491-1899 if any suspicious pests or symptoms of HLB are found.
  • Do not bring any plant material into California from other states or countries and do not move citrus plants out of quarantined areas, because they might be carrying psyllids or be infected with HLB.
  • Only buy citrus trees from reputable, licensed California nurseries.
  • Dry or double bag plant clippings before placing in green waste recycle bins to avoid moving psyllids and HLB-infected plant material.
  • Cooperate with agriculture officials on detection and suppression efforts of the Asian citrus psyllid and HLB.
For more information and to find out what to look for, visit the California Citrus Threat website or view the Save Your Citrus Brochure (PDF), with helpful info about the Citrus pest & Disease Prevention Program.