Leaching of Indaziflam Applied at Two Rates Under Different Rainfall Situations in Florida Candler Soil

Indaziflam {N-[(1R, 2S)-2,3-dihydro-2,6-dimethyl-1H-inden-1-yl]-6-[(1RS)-1fluoroethyl]-1,3,5-triazine-2,4-diamine} is a new pre-emergence herbicide recently registered for a broad spectrum weed control in Florida citrus. Experiments were conducted to evaluate leaching of indaziflam applied at 73 and 145 g ai ha−1 in Florida Candler soil under simulated rainfall of 5, 10, and 15 cm ha−1. Indaziflam leached the least (12.6 ± 0.6 cm) when applied at 73 g ai ha−1 under 5 cm ha−1 rainfall. Indaziflam leached furthest (30.2 ± 0.9 cm) when applied at 145 g ai ha−1 under 15 cm ha−1 rainfall. The visual control ratings of a bio-indicator species ryegrass (Lolium multiflorum L.) was 97% at 15 cm ha−1 rainfall when indaziflam applied at 145 g ai ha−1 in the 26 to 30 cm horizon indicating the maximum movement and activity of indaziflam. A dose response experiment was conducted to determine the sensitivity of ryegrass to various doses of indaziflam that confirmed that application of indaziflam at 29.20 g ai ha−1 was sufficient to prevent germination of ryegrass. There was no mortality of ryegrass plants beyond the 30 cm and the biomass of ryegrass was comparable with untreated control indicating that indaziflam did not leach beyond this distance even under 15 cm ha−1 rainfall.