Effect of imazamox, fomesafen, and acifluorfen soil residue on rotational crops

Abstract

Field studies were conducted at Goiânia, GO, Brazil, on an Oxisol (clayey, kaolinitic, isothermic, Typic Haplustox) and at Jussara, GO, Brazil, on an Oxisol (loamy sand, kaolinitic, isothermic, Typic Haplustox) during 1995 and 1996 to determine the carryover effect of fomesafen, imazamox, and acifluorfen, applied to edible bean, on rotational crops (maize, sorghum, rice, and millet) and to estimate the level of soil residues under Brazilian Savanna conditions. Averaged across locale, year, and rate, fomesafen dissipation time (DT50) (37.5 d) was longer than acifluorfen (27.5 d) and imazamox (25.9 d). For both locations, soil herbicide persistence (average of herbicides) was longer in 1995 than in 1996. This was due to higher soil moisture content in 1996. The sensitivity of rotational crops to fomesafen and imazamox residues was, in decreasing order: sorghum, corn, millet, and rice, and for acifluorfen: sorghum, corn, rice, and millet. The period between herbicide application and rotational crop planting (PAP) varied in agreement with the sensitivity of rotational crops to herbicide residues in soil and the persistence of the herbicide. Considering both location and year, the PAP for fomesafen (250 g ai ha−1) ranged from 69 to 132 d for corn, 114 to 179 d for sorghum, 29 to 95 d for rice, and 52 to 111 d for millet; the PAP for imazamox (40 g ai ha−1) ranged from 68 to 111 d for corn, 78 to 139 d for sorghum, 25 to 75 d for rice, and 40 to 102 d for millet; and the PAP for acifluorfen (170 g ai ha−1) ranged from 56 to 89 d for corn, 96 to 139 d for sorghum, 61 to 95 d for rice, and 43 to 82 d for millet.

Dissipation of Fomesafen in New York State Soils and Potential to Cause Carryover Injury to Sweet Corn

“…Data fit the first-order multicompartment model well with all but one curve having R 2 values above 0.90 ( Figure 1). DT 50 values were consistent with those published by Mills and Simmons (1998) and Cobucci et al (1998). Values ranged from 28 to 66 d, with a mean of 50 d. Because soil samples were pooled within a given fomesafen rate 3 application treatment, no statistical comparisons could be made across treatments.…”

“…Average number of days after treatment required for 50% reduction in residue concentration (DT 50 ) reported in the Herbicide Handbook (Vencill 2002) for these related herbicides are 30 to 40 d (oxyfluorfen), 3 d (lactofen), 14 to 60 d (acifluorfen) and 100 d (fomesafen), but published values from field trials generally give DT 50 values less than 100 d for fomesafen. Mills and Simmons (1998) reported a DT 50 value of 49 to 56 d and values of 37.5 d and 11.5 to 15.2 d were reported by Cobucci et al (1998) and Lu and Zhu (1996), respectively.…”

Persistence and Carryover Effect of Imazapic and Imazapyr in Brazilian Cropping Systems1

“…Ten 12-cm-diameter soil samples per plot were collected to a depth of 10 cm in all plots at 0, 30, 60, 90, and 120 DAT and stored in a freezer until they were analyzed by the cucumber bioassay as described by Cobucci et al (1998) and by high-performance liquid chromatography analysis using the procedure of Rodrigues et al (2000). In the cucumber bioassay, soil from each treatment was placed in four 1.5-kg plastic pots and five seeds of cucumber (Caipira 8 ) were planted in each pot.…”

Transplanted Pepper (Capsicum annuum) Tolerance to Selected Herbicides and Method of Application

“…Fomesafen, a diphenylether herbicide, is registered for POST application for control of dicot species in soybean [Glycine max (L.) Merril]. It has residual soil activity (Cobucci et al, 1998;Weber, 1993) with a half-life ranging from 6 to 12 months (Johnson and Talbert, 1993). Sulfentrazone provides effective weed control of many dicot and grass weeds in soybean (Krausz et al, 1998) and tobacco (Hancock, 1998;Walker et al, 1998).…”