Gary Bergstrom has confirmed that tar spot has been found and confirmed in corn in two locations in Erie County. We have been talking about the possible arrival of tar spot for years. Earlier this season it had been confirmed in Erie County PA and just across the border in Ontario Canada. The following are Gary’s advice for identifying tar spot in your corn field. “Attached are two photos of corn leaves affected by tar spot in Erie County. These show nicely the range of sizes of glossy black stromata, the fruiting bodies and overwinter survival structures of the fungus. For diagnosis, it’s all about the stromata. They can’t be wiped off like insect frass can. Chlorotic or necrotic lesions won’t be that helpful at this stage as other foliar diseases and senescence will likely co-occur on the same leaves. The stromata remain highly visible on frosted or completely senesced leaves. This provides an opportunity to scout for stromata on foliar residues in harvested fields! I’ll have a blog article together soon for wider sharing.” We would expect to find tar spot in Chautauqua, Erie and Niagara counties.
If you think you have found tar spot in your corn, please give Mike Stanyard a call or text pictures to 585-764-8452 or email at mjs88@cornell.edu.
