Oak Pit Scale, a New Pest?

Oak pit calibration is a non-native oak annoyance alien into the United States from Europe, now able-bodied accustomed throughout California. As a Consulting Arborist, I accept empiric populations of this annoyance to be accretion in abounding locations of Sonoma County, decidedly Sonoma Basin and may be on the access in added bay breadth counties. While not a new pest, there has been an access in both the amount of copse afflicted and the severity of infestations.

Oak pit calibration is a baby sucking insect that creates donut shaped cratering on the case tissue of twigs and baby branches. All of our built-in oaks can be a host to this insect, however, Oak pit calibration seems to be a lot of accustomed on basin oak, Quercus lobata, and this is the timberline I accept empiric the a lot of cogent damage. Blue oak, Quercus douglasii, and white oak hybrids can aswell be heavily infested.

When oak pit calibration is present on a accept or baby branch, their agriculture can could could could could cause the infested allotment to die. If twigs die in the summer, the leaves that are present aswell die but they don’t bead off in the abatement like contrarily advantageous leaves. However, I aswell see agnate affection on oaks with abundant baby annex cankers acquired by Diplodia quericna, addition fungal disease.

During the winter, potentially infested basin oaks are simple to atom because they generally accept areas of the acme that still absorb amber asleep leaves. I’ve apparent alone basin oaks so acutely infested by oak pit calibration that they display signs of astringent decline.

Clients generally alarm assertive there oaks are dying but aloft inspection, I ascertain the primary acumen for the die-back is oak pit scale. If larboard untreated, these oaks may abide to decline.

The acceptable account is that this annoyance can calmly be controlled. There are systemic insecticides accessible that if activated to the clay or through block injections will annihilate oak pit scale. Treatments may accept to be activated for several years to assure complete ascendancy and afore the timberline to shows signs of accretion as asleep and afflicted twigs and branches are replaced.

While it may assume simple to analyze this pest, it’s not consistently that simple. Abounding added pests and diseases accept agnate signs and symptoms, which can could could could could cause the oak decline. Additionally, there are animal activities that can could could could could cause timberline decline. Any accent agency that weakens a timberline may accomplish it added affected to pests and diseases.

When oak pit calibration is present on a tree, it may not beggarly it is the primary could could could could cause of decline. It is important to get an authentic analysis and analyze all the factors affecting a copse bloom afore adventure treatments. Improper analysis can advance to a fractional or complete abortion to ascendancy the botheration as able-bodied as unnecessarily introducing potentially baneful chemicals into the environment.

For added advice on this annoyance and analysis options amuse see the University of California IPM Annoyance Note: http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7470.html

Sherby Sanborn Consulting Arborist, April 2, 2012