Environmental effects on CGA-248757 and flumiclorac efficacy/soybean tolerance

Abstract

The effect temperature, light intensity, time to initial light exposure, relative humidity, and the presence of dew have on CGA-248757 and flumiclorac efficacy was evaluated in laboratory trials. Increasing temperature from 10 to 40 C increased CGA-248757 and flumiclorac activity on common lambsquarters by 79 and 87%, respectively. Similarly, increasing temperature from 10 to 40 C increased CGA-248757 and flumiclorac activity on redroot pigweed by 68 and 60%, respectively. Increasing light intensity from 0 to 1,000 μmol m−2 s−1 increased CGA-248757 activity on common lambsquarters and redroot pigweed by 92 and 93%, while flumiclorac activity increased 91 and 99%. Time to initial light exposure and relative humidity did not affect CGA-248757 or flumiclorac activity on common lambsquarters and redroot pigweed. The presence of dew reduced herbicidal activity of both compounds on common lambsquarters by 5% and redroot pigweed control with CGA-248757 and flumiclorac by 21 and 20%, respectively. Field applications of CGA-248757 or flumiclorac at 6:00 A.M., 2:00 P.M., and 10:00 P.M. indicate environmental conditions at application strongly influence soybean tolerance and weed control with CGA-248757 and flumiclorac. The greatest soybean injury occurred from CGA-248757 or flumiclorac applications at 6:00 A.M. compared with applications at 2:00 P.M. or 10:00 P.M. Common lambsquarters control was greatest when CGA-248757 or flumiclorac was applied at 6:00 A.M. or 2:00 P.M. compared with 10:00 P.M. However, redroot pigweed control was greatest when CGA-248757 or flumiclorac was applied at 2:00 P.M. Application time of day did not affect velvetleaf control with either herbicide.

Amino acid content and biomass productivity of selected weed species as an indicator of their response to herbicide stress

“…Moreover, this study showed greater biomass reduction under warm conditions for the mixtures 2.4-D+dicamba and 2.4-D+florasu-lam. These results are in agreement with the previous reports describing higher herbicide activity under high temperature conditions compared to low temperature [5,16,17]. In contrast to temperature, relative humidity did not influence weed response to herbicide stress.…”

“…In contrast to temperature, relative humidity did not influence weed response to herbicide stress. Similar results were reported by F a u s e y and R e n n e r [17], but generally this finding is inconsistent with most of the previous papers that have proven a weaker response of weeds to herbicides at low relative humidity [4,18,19]. The lack of differences in weed response proved in this research may be due to the small differences between the relative humidity levels tested.…”

Influência do orvalho na eficiência do glyphosate sobre Brachiaria decumbens

“…Na última avaliação, aos 35 DAA, o volume de orvalho de 500 mL m -2 apresentou o melhor controle, atingindo 30%. Esse baixo controle foi provavelmente devido à perda do glyphosate por escorrimento, concordando com Fausey & Renner (2001).…”

Environmental and physiological factors that affect the efficacy of herbicides that inhibit the enzyme protoporphyrinogen oxidase: a literature review

“…High temperatures favor the activity of PROTOX inhibitors (Li et al, 2000;Fausey & Renner, 2001;Price et al, 2004;HattermanValenti et al, 2011. ) For example, in experiments using flumiclorac and fluthiacet, it was found that a temperature rise from 10 o C to 40 o C increased weed control under greenhouse conditions.…”