Impact of Antimicrobial Compounds on Etiolation Caused by Xanthomonas translucens and on Turf Quality of Creeping Bentgrass Putting-Green Turf

Etiolation is an abnormal elongation and chlorosis of turfgrass plants that has become problematic in recent years, and bacteria have been implicated as causal agents. The frequent reports of etiolation are of concern to turfgrass managers, since management practices for bacterial diseases in turf are not well developed. The purpose of this research trial was to evaluate fungicides and nonregistered antibiotics for management of etiolation in creeping bentgrass turf. This 2-year field study evaluated oxytetracycline, streptomycin sulfate, acibenzolar-S-methyl + chlorothalonil (ASM + C), potassium phosphite (PPP), hydrogen dioxide, fosetyl-Al [pigmented (FAP) and nonpigmented (FA)], and copper + mancozeb for their effects on etiolation caused by Xanthomonas translucens on creeping bentgrass putting-green turf. Reductions in etiolation severity were observed with oxytetracycline treatment in both years and with ASM + C in the second year of study. While ASM + C did not reduce etiolation in the first year, turf quality with ASM + C alone and in combination with PPP was superior to all other treatments in both years. While PPP and FAP did not reduce etiolation, turf quality of these plots was often better than the control. Both antibiotics in addition to copper + mancozeb had phytotoxicity that reduced turf quality. Preventative applications of ASM + C were the most effective in reducing etiolation of creeping bentgrass while maintaining turf quality.