Midwest Vegetable Trial Reports

Date of this Version



tomato, plant diseases and disorders, Solanum lycopersicum, discoloration, sunburn, yellow shoulder disorder, potassium fertilizers, fertigation


Tomatoes grown in unheated high tunnels can suffer significant loss in quality due to yellow shoulder disorder, particularly in susceptible varieties. This paper reports on a preliminary trial to determine whether incidence and severity of the disorder could be influenced by applying potassium fertilizers. Plots with higher leaf potassium content tended to have less fruit with severe yellow shoulder disorder, but increasing the amount of potassium fertilizer applied did not significantly reduce the disorder. From this study it isn’t possible to make specific recommendations for reducing yellow shoulder disorder with potassium applications.


Originally published in Midwest Vegetable Trial Report for 2016. Compiled by Elizabeth T. Maynard and Brad Bergefurd, Dept. of Horticulture and Landscape Architecture, Office of Agricultural Research Programs, Purdue University, W. Lafayette, Indiana. February 2017