The impact of glyphosate isopropylamine salt and glufosinate-ammonium on some soil pathogens causing disease in wheat

Glyphosate isopropylamine salt and glufosinate-ammonium are commonly used herbicides for presowing or host-harvest weed control in Turkish wheat fields. Although many studies have been conducted on their efficacy against weeds, limited studies are available in the literature on their impact on soil pathogens causing disease in wheat, such as Fusarium culmorum, Gaeumannomyces graminis var. tritici, and Bipolaris sorokiniana. In this in vitro study, the efficacy of glyphosate isopropylamine salt and glufosinate-ammonium on the mycelial growth of these pathogens grown in PDA was investigated. Changes in the mycelial growth of fungal species grown in herbicide-amended PDA medium and control medium were observed by measuring the radial growth of the colonies three times per week. Glufosinate ammonium effectively suppressed the fungal growth of all of the pathogens tested in vitro. Glyphosate isopropylamine salt induced mycelial growth of B. sorokiniana; however, there was little or no impact of the herbicide on other pathogens tested. Wheat growers should be careful using glyphosate isopropylamine salt in fields that are infected by B. sorokiniana, or they should use glufosinate-ammonium in fields where these pathogens are common.