In field observations and studies by Brad Hanson, the University of California weed specialist says gumming and a sunken canker can occur three to five weeks after a herbicide application.

A glufosinate-caused canker is different from Phytophthora, bacterial canker and band canker. There is more consistency of symptoms across the field – a pattern in symptom occurrence.

Within a few years – and usually by the first harvest – Doll says affected areas appear compartmentalized by the enlarging trunk and are rarely visible.

“Tree loss has not been observed in normal drift incidences.”

Doll calls glufosinate a useful tool for postemergent weed control.

As with any herbicide, he recommends grower use with caution around young trees and to avoid sprays in windy conditions.

Use the right equipment and pressure to avoid spray drift.

Dr. David Doll is the University of California Cooperative Extension pomology farm advisor in Merced County. This information is from The Almond Doctor website and is used with Dr. Doll’s permission.