Effect of environmental conditions on velvetleaf and giant foxtail epicuticular wax quantity and quality and the relationship to herbicide penetration

Abstract

Pitty, Abelino, "Effect of environmental conditions on velvetleaf and giant foxtail epicuticular wax quantity and quality and the relationship to herbicide penetration " (1988). Retrospective Theses and Dissertations. 9716.

Effect of Drought Stress on Velvetleaf (Abutilon theophrasti) and Bentazon Efficacy

“…Control velvetleaf produced 5.3 and 4.8 g of dry weight for velvetleaf subjected to -0.03 and -0.4 MPa \(fP, respectively. Drought stress has been reported to increase epicuticular leaf wax production (8,14,16). Recent data, however, suggest that epicu ticular leaf wax is not an effective barrier for U A N (18).…”

“…Reasons for this reduction, however, are not well understood. Pitty (16) found that bentazon penetration was reduced in drought-stressed velvetleaf. Drought stress reduced acifluorfen {5-[2-chloro-4-(trifluoromethyl) phenoxy]-2-nitrobenzoic acid} activity (19).…”

“…Drought stress reduced acifluorfen {5-[2-chloro-4-(trifluoromethyl) phenoxy]-2-nitrobenzoic acid} activity (19). Acifluorfen penetration was greater in drought-stressed velvetleaf when the adjuvant 28% urea ammo nium nitrate (UAN) 4 was used instead of crop oil concentrate (COC) 4 (16). UAN has also been reported to enhance velvetleaf control (6,13).…”

Evaluation of Methods to Quantify Herbicide Penetration in Leaves1

“…The scintillation cocktail best suited to quantify radioactivity for each herbicideweed treatment was determined based on both manufacturer's recommendations and maximum count efficiency (Table 1). Product A was similar to the scintillation cocktail used as a leaf wash by Pitty (1988) who reported that the cocktail was a 3:1 (v/v) mixture of xylene and Triton X-114 (octylphenoxypolyethoxyethanol) with 2,5-diphenyloxazole (PPO) added at 4 g/L.…”

“…The methods of 14 C-herbicide application and quantification were essentially consistent among researchers. However, the leaf wash methods utilized different compounds, including chloroform (Hinz and Owen 1996;Levene and Owen 1995), toluene-ethanol mixture (Olsen and Nalewaja 1982), methanol (Breeze et al 1992;Feng et al 1998), ethanol (Mabb and Price 1986;Price 1982), Triton 4 X-100 (Hageman and Behrens 1984), and xylene-Triton X-114 mixture (scintillation cocktail) (Pitty 1988). Historically, all methods, except the scintillation cocktail mixture, have been acceptable.…”