This stunted apple tree, which has a large basal canker, is in an orchard where the grower used glyphosate alone three to four times a year to control weeds. Cuts on the margin of the canker show healthy green tissue. Growers often express concern that a herbicide program using glyphosate (e.g., Roundup) may not be totally safe for their trees. Some won’t use the herbicide when trees are young. Most use directed sprays, shields, and tree guards to protect tree trunks and low limbs when killing weeds in strips under the trees. Others paint tree trunks to provide protection. Now, […]