Research Summary Abstract
From 2003 to 2017, numerous products representing 23 active ingredients were evaluated in greenhouse trials as soil drench against Thielaviopsis basicola causing black root rot on ornamentals. Although there were insufficient data for definitive conclusions, two new experimentals (BAS 750 – mefentrifluconazole) and A20808C showed promising efficacy comparable to the standards. Several products that are not yet labeled for Thielaviopsis basicola also showed promising efficacy in single trials. These include Empress Intrinsic (pyraclostrobin), Endorse/Veranda O (polyoxin D), Mural (azoxystrobin + benzovindiflupyr), Tourney (metconazole) and Vital (potassium phosphite). The experimentals A19649B and Pyraziflumid SC (pyraziflumid) provided poor efficacy in single trials. The established standards 3336 and Terraguard generally provided excellent efficacy.