Bob Mulrooney, Extension Plant Pathologist; bobmul@udel.edu
Be on the lookout for buckeye rot when we get wet weather and wet soils. This is more a problem on tomatoes grown on flat culture because the fungus is soil borne. Staked tomatoes generally are not affected unless soil splashes onto the fruit. Symptoms of Buckeye Rot on green fruit include brownish-tan lesions that have a definitive concentric appearance. As lesions form the fruit will begin to soften up, this is quite different than Late blight which will cause a dark brownish/ black lesion with the fruit remaining somewhat firm. Unlike Late blight, Buckeye rot won’t attack the foliage. For more information on control please see the 2010 Delaware Commercial Vegetable Production Recommendations.
Buckeye rot on tomato fruit