What can cause leaf tip scorch on redwood trees?

Leaf tip scorch symptoms on redwood trees are found from the lower to upper canopy and include healthy leaves interspersed with brown and grey leaves or portions of leaves. Grey leaves typically have black margins into the healthy tissue. Such symptoms are typically caused by a fungus called Pestalotiopsis funerea. They are commonly associated with […]

What are the modifications required for drone canopy leaf sampling?

Make sure the prop blades are protected. Modify the tail to include a collection device.  A very sharp blade at a sharp angle allows twigs to be cut off and often to remain caught in the space between the blade and tail. Learn how to drive the drone using the camera. For more on drones […]

When treating large oak trees with phosphonate, is it more effective to topically apply or inject the material?

Injections may be better for large trees with a regular shape, while topical applications may be better for large, irregular, gnarly trees.

What temperature range is acceptable for treating oak trees with phosphonate?

In order to obtain maximum efficacy with oak phosphonate treatments, minimum temperatures should not be below 50 ºF. Maximum daytime temperatures should be higher than 60 ºF, but not exceed 85 ºF.    

Do azomite fertilization and lime wash treatments help control SOD?

Based on the study published by the UC Berkeley Garbelotto lab in California Agriculture (http://nature.berkeley.edu/garbelotto/downloads/calag2009.pdf), azomite and/or lime washes alone are not effective in controlling SOD.

Will the spray application for SOD prevention be updated like the injection application was?

While phosphonate injections to help control SOD are now recommended once every 2 years, spray applications should still be applied to the bark of oak trees annually.

Can poison oak leaves be infected by Phytophthora ramorum?

The stems of poison oak plants can be infected by Phytophthora ramorum (the plant pathogen known to cause SOD); however, we do not know if leaves can be.

Can poison oak leaves get infected by Phytophthora ramorum?

The stems of poison oak plants can be infected by Phytophthora ramorum (the plant pathogen known to cause SOD); however, we do not know if leaves can be.

Bark beetles are attacking my oak. Will they kill the tree? What should I do?

Once bark beetles attack the main stem (trunk) of an oak, the tree is on its way out.  Insecticide treatments will not save it. Oak beetles are attracted to trees that are severely compromised.  They cannot attack healthy trees. The correct approach to avoid bark beetle infestations is not to apply insecticides, but rather to […]

How often should SOD phosphite treatments be applied?

If SOD phosphite treatments are being applied by injection November 1st – December 15th, data has shown that treating every 2 years is sufficient. When preparing the injections, be sure to use the most current dosage recommendations as they have recently been updated. Current recommendations can be found at http://nature.berkeley.edu/garbelottowp/?page_id=2345. The new dosages are significantly […]

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