Protecting Oaks from Disease & Insects Insects & Diseases Keep Your Trees Healthy and Resilient Oak Wilt and Two-Lined Chestnut Borer (TLCB) are two of the most serious threats facing Minnesota oaks. Both can cause rapid decline and even tree death, but with proactive care, the worst-case scenarios are often preventable. Why Oak Protection Matters Oak wilt spreads rapidly through root systems and is deadly to both red oaks and white oaks (though white oaks often take longer to die). There is no effective treatment for symptomatic red oaks, but white oaks can be treated if the disease is detected early. Two-lined chestnut borer targets trees already weakened by drought or damage. Typically, this insect isn’t immediately fatal, but recent environmental stress in Minnesota means trees with TLCB infestations are dying more rapidly, sometimes within months. Together, oak wilt and TLCB represent a serious and growing threat to oak populations across the state, but with expert care and early intervention, you can protect your trees. At SavATree, our ISA Certified Arborists are ready to help. Signs & Symptoms of Oak Wilt Oak Wilt: Rapid leaf browning and drop, often starting at the crown Progressive branch dieback Sudden wilting—especially in red oaks Two-Lined Chestnut Borer: Thinning canopy and upper branch dieback Small D-shaped exit holes in bark (often not visible until damage is advanced) General decline, especially in stressed or damaged trees Note: These symptoms can overlap with other oak health issues, making professional diagnosis important. Prevention & Treatment Schedule treatments during summer, when intervention is most effective, but avoid pruning oaks during the high-risk window (April–July) to reduce disease spread. Maintain tree health with proper watering, mulching, and fertilization. Remove and properly dispose of infected trees to limit spread. Consider preventive systemic treatments for high-value oaks, including injections or soil treatments. Schedule a professional assessment to identify site-specific risk factors. With early action and expert care, many oak health issues can be prevented managed before they become severe. Stop Oak Diseases Before They Spread Oak wilt and borer damage can progress quickly, sometimes faster than homeowners expect. Early action gives you the best chance to protect your trees and avoid costly removal or replacement. SavATree offers a combined Oak Wilt plus Borer Treatment, which is a strong option for stressed trees facing both threats. Our proprietary ArborKelp® and ArborHealth® treatments can help improve tree resilience, and our ISA Certified Arborists will tailor care recommendations specific to your property. Contact us today to schedule a consultation with an expert arborist.