August 28, 2020 – Woodridge Park District staff recently met with the head pathologist from the Morton Arboretum to address the decline in health of several oak trees at Castaldo Park. The primary reason contributing to the decline and death of these oaks (just as what is happening at Morton Arboretum and all around our region) is environmental stress stemming from the gypsy moth defoliation in 2008; the drought of 2012; and high park use. Secondary reasons for the oak issues were also identified as bur oak blight (a fungus), and an insect infestation of two-lined chestnut borers and bark beetles.
Several steps were identified as ways to help to improve the health of the oaks at Castaldo Park:
1. Mulch the oaks to retain water and protect from mower damage. Park District staff began this process earlier this year with work 60% complete to date and will continue through the fall.
2. Water the oaks that are showing stress. Park District staff began watering the week of August 24 and intends to actively water the oaks twice a week through mid-October (weather pending).
3. Treat the oaks in three recommended ways: Growth regulator, insecticide, and fungicide. Growth regulator was watered into the base of the tree and then mulched over on August 28. Insect control treatments will be applied to the base of the trees and covered with mulch (scheduled the week of September 7, 2020). Lastly, fungicide application is planned for the spring 2021 (best time recommended for application).