Diagnosing Herbicide Injury on Rose of Sharon and Leaf Necrosis on Ornamental Pear

Diagnosing Herbicide Injury on Rose of Sharon and Leaf Necrosis on Ornamental Pear

Nursery worker seeks diagnosis for two customer samples:

Rose of Sharon

• Mature, healthy until now.
• Lower half leaves: narrowed, cupped, reduced.
• No cankers, insects, mites, fungi. No glyphosate history.
• Suspect: Growth-regulator herbicide drift/uptake (e.g., 2,4-D, dicamba). Causes leaf strapping/cupping.

Ornamental Pear

• Midvein necrosis spreading to leaf blade.
• Dark circular lesions with rust centers.
• Generalized distribution, 2 years in ground.
• Need photos for accurate ID (fire blight, pear scab, fungal leaf spot possible).

Next Steps

1. Ask customer about any herbicide use nearby (lawn, farm, right-of-way).
2. Check nearby plants for similar symptoms.
3. Get clear photos of pear leaves (3–5 representative leaves).
4. Monitor if spreading.

Herbicide injury on woody plants often mimics virus/phytoplasma but is environmental.