Cercospora zeae-maydis spore
Figure 1. Life cycle of gray leaf spot Cercospora zeae-maydis in corn. Spores and lesions are enlarged to show detail.
GLS lesions begin as small necrotic spots with chlorotic halos.
As GLS develops, lesions become blockier in appearance and more gray in coloration.
Table 1. Estimated yield loss based off of percent of tissue infected by gray leaf spot (Lipps, 1998).
Figure 2. Average yield increase of hybrids, with varying levels of resistance to GLS, due to a foliar fungicide application in a three- year University of Tennessee/Pioneer research study with very high GLS pressure.
Table 2. Fungicide efficacy for control of gray leaf spot. (Wise, 2019).
Author: Madeline Henrickson
August 2019
The foregoing is provided for informational use only. Please contact your Pioneer sales professional for information and suggestions specific to your operation. Product performance is variable and depends on many factors such as moisture and heat stress, soil type, management practices and environmental stress as well as disease and pest pressures. Individual results may vary.