The U of I plant clinic has received numerous phone calls from homeowners regarding premature leaf drop in ash (Fraxinus spp.).
We don’t know what is causing the premature leaf drop, however, stress induced by last year’s drought and scorching summer heat are certainly factors. Additional factors worth considering are emerald ash borer, verticillium wilt, and other environmental stressors.
Here are your top three options:
1. Ensure your yard trees receive supplemental water during periods of drought
2. Submit a specimen sample to the U of I Plant Clinic for analysis/culture: http://web.extension.illinois.edu/plantclinic/submitasample.cfm
3. Contact a certified arborist for an on-site inspection of the tree.