Evaluation of Fungicide Applications for Improved Plant Health in Grain Sorghum.

Based on recommendations from fungicide manufacturers, producers are applying fungicides to grain sorghum to enhance plant health and to increase yields, even in the absence of foliar disease symptoms. To address this practice, two foliar fungicide trials were conducted in the Upper Gulf Coast Region of Texas.  The objective of these two studies was to determine if there was a yield increase or economic benefit of applying a fungicide to grain sorghum in the absence of disease pressure.  Foliar fungicide applications were made when grain sorghum reached 25% bloom.  Fungicides evaluated in these studies included Headline®, Quadris®, and Topguard®. Beginning at 25% bloom, leaf temperature and Spad or chlorophyll readings were taken to determine if there were differences between the fungicide treatments. These measurements were taken on a weekly basis until the grain sorghum reached physiological maturity.  At harvest, percent lodging, percent grain moisture, bushel weight, and grain yield were measured.  Following harvest, grain samples were evaluated to see if differences in surface grain mold and total nitrogen in the seed were evident.  Foliar fungicide application did not increase grain yields and no differences were found in the other variables that were measured.