Tree Pests to Watch

Be on the look out for these tree pests and diseases!

• Invasive Shot Hole Borer (ISHB)
• Goldenspotted Oak Borer (GSOB)
• Foamy bark canker and Western Oak Bark Beetle (WOBB)
• Sweet gum leaf scorch (Xylella)
• Emerald Ash Borer (EAB)
• Laurel Wilt
• Asian Citrus Psyllid (ACP) and Huanglongbin (HLB)

Quick reference guide for symptoms 

 Small holes created by burrowing beetles

If <0.1 inch in diameter, it may be ISHB

If >0.1 inch in diameter, it may be WOBB

D-shaped beetle emergence holes

It is more likely to be GSOB, which is currently found in California

However, EAB is a fast spreading pest that is currently NOT in California, but is predicted to reach California in the near future

Asymmetrical yellowing of leaves

Symmetrical yellowing is a common indicator of environmental stressors such as drought/poor watering or nutrient deficiencies

Asymmetrical yellowing may be indicative of an infestation of ACP or bacterial scorch caused by Xyella 

Wilted green leaves

Wilted green leaves that eventually turn brown and remain on the tree may be Laurel Wilt

Wilted leaves with branch dieback and canopy loss may be ISHB

Discharge from beetle holes

White, crusty ring of sugar found on avocado or box elders is likely ISHB

Reddish sap initially, followed by cream-colored foamy liquid is likely WOBB

Sawdust, toothpick-like projections are likely redbay ambrosia beetles, which spread Laurel Wilt