Adding XtendiMax® herbicide with VaporGrip® Technology, a restricted use pesticide, increased control of broadleaf weeds in almost all cases at both 21 and 35 days post application. This effect was seen most strongly for large-seeded broadleaf species like giant ragweed, velvetleaf, and morning glory species.
Adding XtendiMax herbicide improved control of problematic Amaranthus species like Palmer amaranth, waterhemp, and other pigweed species in 3 of the 6 pre-emerge products at 35 days post application.
Determine if XtendiMax herbicide delivers a broadacre benefit of residual broadleaf weed control when used with pre-emergence (PRE) residual herbicides in a conventionally tilled soybean system.
Bayer worked with university researchers to choose 15 sites across 12 states (AR, IA, IL, LA, MI, MN, MO, NC, ND, NE, SD, and WI) to conduct their trial. Out of the 12, 11 sites provided usable data. The selected sites represented various soil types and environmental conditions.
The trial’s protocol included conventional tillage before planting in order to remove any existing weeds.
Preemergence (PRE) products were applied prior to soybean emergence or at planting.
The trial did not use post-emergence (POST) applications to determine the effective length time of PRE residual products.
Researchers evaluated weed control 14, 21 and 35 days after treatment (DAT).
At 21 DAT, the percent broadleaf weed control fell anywhere from 83-92% for the preemergence products only and 95-97% control with the addition of XtendiMax herbicide. Control across all locations with XtendiMax herbicide was more consistent (Figure 1).
At 35 DAT, control was more consistent across locations and improved over base PRE applications (Figure 2).
MON 301886, Warrant Ultra Herbicide, Valor EZ herbicide, and Authority MTZ herbicide treatments saw improved performance at 21 days after application with the addition of XtendiMax herbicide (Figure 1). All products with the addition of XtendiMax herbicide saw a higher level of control at 35 DAT than initial PREs alone (Figure 2).
Looking at Amaranthus species alone 35 days after application, Fierce® EZ herbicide, Valor® EZ herbicide, and Authority® MTZ herbicides were improved when XtendiMax herbicide was added (Figure 3).
Focusing on large-seeded broadleaf species, the addition of XtendiMax herbicide significantly improved control in 5 out of 6 PRE products at 21 days after application and all products at 35 days post application (Figures 4 and 5).
Figure 1. Average percent control of broadleaf weeds with pre-emergence products alone and with XtendiMax herbicide at 8 locations 21 days after application (Averages followed by the same letter are not significantly different using Fisher's Protected LSD at <0.05).
Figure 2. Average percent control of pre-emergence products alone and with XtendiMax herbicide at 9 locations 35 days after application. (Averages followed by the same letter are not significantly different using Fisher’s Protected LSD at <0.05).
Figure 3. Average percent control of Amaranthus species with pre-emerge products alone and with XtendiMax herbicide at 7 locations 35 days after application. (Averages followed by the same letter are not significantly different using Fisher’s Protected LSD at <0.05).
Figure 4. Average percent control of large-seeded broadleaf species with pre-emerge products alone and with XtendiMax herbicide at 7 locations 21 DAT. (Averages followed by the same letter are not significantly different using Fisher’s Protected LSD at <0.05).
Figure 5. Average percent control of large-seeded broadleaf species with pre-emerge products alone and with XtendiMax herbicide at 8 locations 35 DAT. (Averages followed by the same letter are not significantly different using Fisher’s Protected LSD at <0.05).