Effect of Commercial Adjuvants on Vegetable Crop Fungicide Coverage, Absorption, and Efficacy

The addition of an appropriate adjuvant with foliar fungicide can significantly improve coverage, absorption, and efficacy. Laboratory and field studies evaluated coverage, absorption, and efficacy of commercial adjuvants with diverse chemistries on multiple host-pathogen systems. Organosilicone-based adjuvants improved coverage by 26 to 38% compared with a latex spreader-sticker and water. Significant crop by coverage interaction effects were also detected. The organosilicone/methylated seed oil-based adjuvant, Aero Dyne-Amic, significantly improved total [¹⁴C]azoxystrobin absorption on onion and potato by 30 and 21%, respectively, compared with water. The spreader-sticker, Bond, improved [¹⁴C]azoxystrobin absorption on onion and dry bean by 41 and 39%, respectively, compared with water. In experimental field plots, dry bean rust incidence was reduced by 52% when Kinetic or Latron AG-98 was added to maneb compared with maneb alone. The area under the potato early blight disease progress curve was reduced 29, 24, or 21% when Kinetic, Bond, or Latron AG-98 was added to maneb, respectively, compared with maneb applications alone.