Kn. Reddy et al., FOLIAR WASHOFF AND RUNOFF LOSSES OF LACTOFEN, NORFLURAZON, AND FLUOMETURON UNDER SIMULATED RAINFALL, Journal of agricultural and food chemistry, 42(10), 1994, pp. 2338-2343
Lactofen [(+/-)-2-ethoxy-1-methyl-2-oxoethyl hloro-4-(trifluoromethyl)
phenoxy]-2-nitrobenzoate] washoff from velvetleaf (Abutilon theophrast
i Medic.) and common cocklebur (Xanthium strumarium L.) foliage was in
vestigated. Plants were sprayed with lactofen at 0.4 kg of ai ha(-1) a
nd subjected to 2.5 cm of rainfall in 20 min at 1 and 24 h after appli
cation (HAA). At 1 HAA, in both species, over 97% of lactofen was wash
ed off from foliage. At 24 HAA, lactofen washoff ranged from 51% to 82
% in both species. Runoff losses of lactofen, norflurazon [4-chloro-5-
(methylamino)-2-[3-(trifluoromethyl) phenyl]-3(2H)-pyridazinone], and
fluometuron [N,N-dimethyl-N'-[3-(trifluoromethyl)phenyl]urea] on a Bos
ket sandy loam soil in 2.24 m x 1.22 m x 0.25 m fiberglass runoff tray
s with 1.1% slope were also studied. A rainfall of 2.5 cm in 20 min at
24 HAA generated 0.8 cm of runoff and contained 3.2% of applied lacto
fen. However, lactofen loss in runoff was reduced by 94% with a cover
crop of Italian ryegrass (Lolium multiflorum Lam. and crimson clover (
Trifolium incarnatum L.). Norflurazon and fluometuron losses in runoff
from no-crop residue trays were 4.4% and 0.8%, respectively, when a r
ainfall of 3.8 cm in 30 min was applied at 24 HAA. No runoff was obser
ved in cover-crop residue trays. More than one-third of the total loss
of all herbicides occurred in the first liter of runoff.