Wheat Response to Simulated Glyphosate Drift

Abstract

Glyphosate at simulated drift rates representing 12.5, 6.3, and 1.6% of the usage rate of 1,120 g ai/ha (140, 70, and 18 g/ha, respectively) was applied to wheat at first node, boot stage, or at early flowering. At 14 d after treatment (DAT) wheat injury, expressed as bleaching of leaf foliage and growth inhibition, was 40 to 55% for 70 g/ha applied at first node and for 140 g/ha applied at all growth stages. Wheat height 28 DAT was reduced 47% with glyphosate applied at 140 g/ha at first node and was reduced around 26% for 70 g/ha applied at first node and 140 g/ha applied at boot stage. Wheat height was not reduced with glyphosate at 18 g/ha applied at first node or boot stage and with all rates applied at early flowering. Wheat yield was reduced 72% when glyphosate was applied at 140 g/ha at first node, 45% when applied at boot stage, and 54% when applied at early flowering. For 70 g/ha, wheat yield was reduced 25 to 30% for the three application timings. Wheat yield was not reduced for 18 g/ha glyphosate. In another study, six wheat varieties responded the same to glyphosate applied at 140 and 70 g/ha. Wheat height 28 DAT was reduced an average of 34% for 140 g/ha glyphosate and 17% for 70 g/ha applied at first node, but height was not reduced when applied at early flowering. Yield was reduced an average of 58 and 43% for 140 and 70 g/ha applied at first node and 38 and 19% for 140 and 70 g/ha applied at early flowering. In both studies yield reductions in most cases were reflected in reduced spike density, spikelet number per spike, and seed weight.

Physiological Effects of Late Season Glyphosate Applications on Peanut (Arachis hypogaea) Seed Development and Germination

“…In contrast, glyphosate at 80 or 160 g/ha did not reduce kernel mass as compared to the nontreated control. Winter wheat kernel mass reductions of 14% from glyphosate at 140 g ai/ha have been reported when applied at flowering (Roider et al, 2007). Peanut seed mass was reduced to 640 mg/kernel by glyphosate at 75 DAP as compared to the 90 and 105 DAP treatments (Table 4).…”

“…These data indicate that peanut does have some level of glyphosate tolerance, but the exact mechanism of tolerance and why seed germination were not negatively affected is not understood. Given that other species have exhibited reduced seed germination after glyphosate exposure (Roider et al, 2007;Steadman et al, 2006;Yasour et al, 2007;Yenish et al, 2000) but not others (Duke et al, 2003), it is theorized that peanut may have some method of glyphosate metabolism or conjugation that has yet to be discovered. This is an area of potential future research.…”

Chemical Interruption of Late Season Flowering to Improve Harvested Peanut Maturity

“…Glyphosate at the 112 g/ha rate reduced non-irrigated germination compared to the NT-control and HFR-control (Table 1). Reduced germination from glyphosate has been demonstrated in studies in other crops (Roider, et al, 2007;Steadman et al, 2006;Yasour et al, 2007;Yenish and Young, 2000). Others studies showed no impact of glyphosate on germination (Duke et al, 2003;Grey and Prostko, 2010).…”

Kışlık arpanın imazamox’un sürüklenme dozlarına tepkisi

“…Denemelerde Roider et al (2007)'nin metodu modifiye edilerek kışlık arpada kullanılmıştır. Imazamox'un tavsiye dozunun (5 g da -1 ) %12.5, 6.3 ve 1.6'ı oranlarındaki drift dozları (0.625, 0.315 ve 0.08 g a.m. da -1 ), üzerine Teejet XR11002 pülverizatör memesi monte edilmiş ilaçlama kollu CO2 basınçlı sırt pülverizatörü ile uygulanmıştır.…”

“…Total herbisitlerin özellikle glyphosate ve glufosinate'in drifti kültür bitkilerinde önemli fitotoksisiteye ve ürün kayıplarına neden olmaktadır (Roider et al 2007, Miller et al 2003. Selektif herbisitler de kültür bitkilerinde ciddi fitotoksisiteye neden olabilir.…”