Ontario dry bean growers are currently limited to ALS inhibitor herbicides for soilapplied broadleaf weed control; therefore another mode of action is needed. Sulfentrazone is a PPO inhibitor herbicide that has activity on some annual grass and broadleaf weed species. Four field trials were conducted over two years (2014, 2015) to determine the tolerance of four commonly grown dry bean market classes (adzuki, kidney, small red Mexican and white bean) to PRE applications of sulfentrazone at 140, 210, 280 and 420 g·ai·ha -1. Crop injury, plant height, plant density, shoot biomass, seed moisture content and yield were examined. Sulfentrazone (420 g·ai·ha -1) caused up to 74%, 22%, 30%, and 57% injury in adzuki, kidney, small red Mexican and white bean, respectively. Plant density, height and yield were not reduced for kidney or small red Mexican bean. Sulfentrazone (420 g·ai·ha -1) reduced white bean plant density, height and yield by 28%, 29% and 29%, respectively; and reduced adzuki bean plant density, height and yield by 51%, 34% and 57%, respectively. Overall, kidney and small red Mexican bean were the most tolerant to sulfentrazone, followed by white bean, and then adzuki. This study determined sulfentrazone applied PRE is safe for Ontario kidney bean and small red Mexican bean crops.
Dry beans (Phaseolus vulgaris L.) are an important crop for southwestern Ontario. In 2014, over 50,000 ha of white and coloured dry beans were seeded in Ontario, producing 125,000 T with an approximate value of $111,000,000 [
Only two soil-applied broadleaf herbicides are registered for Ontario dry beans- imazethapyr and halosulfuron. Both are group 2, ALS inhibitor herbicides. As there are more than ten documented weed species with group 2 resistance in Ontario [
The objective of this research was to determine the tolerance of four market classes of dry bean to PRE applications of sulfentrazone at 140, 210, 280 and 420 g・ai・ha−1, representing 1×, 1.5×, 2× and 3× registered rate in Ontario.
Four field trials were conducted over a two-year period (2014, 2015) at the Huron Research Station near Exeter, Ontario and University of Guelph Ridgetown Campus in Ridgetown, Ontario, Canada. In 2014, the soil in Ridgetown was a loam with 40% sand, 35% silt and 25% clay, organic matter content of 7.1% and pH of 6.6. In 2015, Ridgetown soil was a sandy clay loam with 53% sand, 27% silt, 20% clay, organic matter content of 5.3% and pH of 7.0. Exeter Site A was a silty clay loam with 18%, 46%, and 36% sand, silt and clay, respectively, with an organic matter content of 4.7% and pH of 7.5. Site B was a loam with 35% sand, 43% silt, 22% clay, organic matter content of 3.6% and pH of 7.6. Seedbeds were prepared by moldboard ploughing in the fall and two passes with a cultivator with rolling basket harrows in the spring.
The experiments were arranged in split-plot design with 4 replicates. Main plots were herbicide rate and subplots were four commonly grown dry bean market classes (adzuki, kidney, small red Mexican and white bean). Plots were 6 m wide (2 rows of each market class spaced 0.75 m apart) by 8 m long in Ridgetown and 3 m (1 row of each market class spaced 0.75 m apart) by 10 m long in Exeter. Dry beans were seeded to a depth of 4 to 5 cm in late May to early June. Different discs were used to adjust the seeding population depending on market class and location as per provincial agronomic recommendations. In Ridgetown, adzuki, small red Mexican and white bean were seeded at a rate of 232,900 seeds∙ha−1 and kidney beans were seeded at 175,500 seeds∙ha−1. At the Exeter locations, adzuki bean was seeded at 272,000 seeds∙ha−1, white bean was seeded at 254,000 seeds∙ha−1, and kidney and small red Mexican beans were seeded at 212,000 seeds∙ha−1. Herbicide treatments included an untreated control and four rates of sulfentrazone (140, 210, 280 and 420 g・ai・ha−1). Herbicides were applied using a CO2 pressurized backpack sprayer and a 1.0 m handheld boom with three ULD 110-02 nozzles (Hypro, New Brighton, MN) spaced 0.5 m apart, calibrated to deliver 200 L∙ha−1 at 240 kPa. Plots were maintained weed-free by hand-hoeing for the entire growing season to eliminate the confounding factor of weed interference.
Crop injury was visually assessed at 1, 2, 3, 4, 6, and 8 weeks after crop emergence (WAE). At 3 WAE, plant density was determined by counting the number of plants in a metre of row for each market class. A metre of row for each market class was then harvested at ground level, placed in separate paper bags, and dried in a kiln. Once dry, the plants were weighed to determine dry shoot weight. At 6 WAE, 10 plants from each treatment were randomly selected for height measurement, and their heights were averaged for each market class. Seed moisture content and yield―adjusted to 15% moisture for adzuki and 18% moisture for kidney, small red Mexican and white bean―were determined at maturity.
All analyses were conducted in SAS version 9.4 (SAS Institute Inc., NC). Fixed effects for the analysis included sulfentrazone rate, bean market class, and their interaction; and their significance was determined with the F-test. Random effects included environment (year-location combination), block nested within environment, rate by environment interaction, market class by environment interaction, and rate by market class by environment interaction. Their significance was determined with the Z-test. The assumptions of normality and homogeneity of the residuals were tested with the UNIVARIATE procedure under various transformations of the data. The transformation that produced the highest Shapiro-Wilk statistic for each data set was selected for the analysis. Data were then subjected to analysis of variance using the MIXED procedure and Fisher’s Protected LSD test with a significance level of 0.05. Data were transformed back to the original scale for presentation.
Statistical analyses determined that the market class by environment interaction was significant for most data sets. This is likely due to the beans responding to the different soil types and weather conditions. However, there were no significant environment, rate by environment interaction, or rate by market class by environment interaction effects, and so data were pooled for the analysis. Analyses revealed that sulfentrazone rate was significant for all assessments, and bean market class was significant for injury at 2, 3, 4, 6 and 8 WAE, plant density, height, shoot dry weight, seed moisture content and yield (
Crop injury symptoms in this study included leaf crinkling and cupping, reduced growth, and reduced plant stand. At 1 WAE, sulfentrazone at 140, 210, 280, and 420 g・ai・ha−1 caused 2%, 4%, 11%, and 35% injury, respectively (
Main effectsb | Dry Bean Injury | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
1 WAE | 2 WAE | 3 WAE | 4 WAE | 6 WAE | 8 WAE | Plant Density | Shoot Dry Weight | Plant Height | Seed Moisture Content | Yieldc | |
% | # m−1 row | g plant−1 | cm | % | T∙ha−1 | ||||||
Dry Bean Market Class | NS | ** | ** | ** | * | * | * | ** | ** | * | ** |
Adzuki | 10 | 13b | 24 | 32 | 12 | 11 | 12 | 0.6c | 33.5 | 15.3a | 1.65 |
Kidney | 5 | 4a | 7 | 6 | 2 | 2 | 14 | 2.7a | 55.2 | 17.1ab | 2.46 |
Small Red Mexican | 7 | 4a | 7 | 5 | 2 | 1 | 16 | 2.3a | 59.0 | 19.4b | 3.39 |
White | 12 | 12b | 21 | 24 | 6 | 3 | 17 | 1.4b | 49.6 | 18.6ab | 3.35 |
Sulfentrazone Rate (g・ai・ha−1) | ** | ** | ** | ** | ** | ** | ** | ** | ** | * | ** |
0 | 0a | 0a | 0 | 0 | 0 | 0 | 17 | 1.8ab | 52.2 | 17.0a | 3.04 |
140 | 2b | 1b | 3 | 2 | 1 | 1 | 15 | 1.8a | 52.4 | 17.2ab | 2.86 |
210 | 4b | 5c | 7 | 9 | 2 | 2 | 15 | 1.7ab | 50.9 | 17.3ab | 2.80 |
280 | 11c | 10d | 17 | 19 | 7 | 5 | 15 | 1.6b | 47.8 | 17.9ab | 2.50 |
420 | 35d | 29e | 38 | 40 | 16 | 9 | 12 | 1.3c | 43.0 | 18.2b | 2.22 |
Interaction | |||||||||||
V × H | NS | NS | ** | ** | ** | * | ** | NS | ** | NS | ** |
aAbbreviations: WAE, weeks after crop emergence; H, herbicide treatment; NS, not significant at P = 0.05; V, dry bean market class. bSignificance at P < 0.05 and P < 0.01 denoted as * and **, respectively. Means were only separated when there was no interaction with that main effect. cAdjusted to 15% moisture for adzuki and 18% moisture for kidney, small red Mexican and white bean.
11% in dry bean treated with 280 g・ai・ha−1 sulfentrazone at 2 WAE, but Hekmat et al. [
Sulfentrazone rate (g・ai・ha−1) | Adzuki Bean | Kidney Bean | Small Red Mexican Bean | White Bean | ||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
Injury 3 WAE | % | |||||||||||
0 | 0 | a | 0 | a | 0 | a | 0 | a | ||||
140 | 2 | b | Z | 2 | b | Z | 2 | b | Z | 4 | b | Z |
210 | 16 | c | Z | 3 | b | Z | 2 | b | Z | 12 | bc | Z |
280 | 35 | cd | Y | 6 | bc | Z | 7 | bc | Z | 29 | cd | YZ |
420 | 64 | d | Y | 22 | c | Z | 21 | c | Z | 54 | d | YZ |
Injury 4 WAE | % | |||||||||||
0 | 0 | a | 0 | a | 0 | a | 0 | a | ||||
140 | 2 | b | Z | 1 | ab | Z | 1 | ab | Z | 4 | b | Z |
210 | 25 | c | Z | 2 | b | Z | 2 | bc | Z | 13 | bc | Z |
280 | 41 | c | X | 5 | bc | Z | 6 | bc | YZ | 33 | cd | XY |
420 | 74 | d | Y | 19 | c | Z | 15 | c | Z | 57 | d | Y |
Injury 6 WAE | % | |||||||||||
0 | 0 | a | 0 | a | 0 | a | 0 | a | ||||
140 | 1 | ab | Z | 1 | ab | Z | 0 | ab | Z | 1 | ab | Z |
210 | 8 | bc | Z | 1 | ab | Z | 1 | b | Z | 2 | bc | Z |
280 | 27 | cd | Y | 2 | b | Z | 3 | b | Z | 10 | cd | YZ |
420 | 58 | d | X | 6 | b | YZ | 5 | b | Z | 33 | d | XY |
Injury 8 WAE | % | |||||||||||
0 | 0 | a | 0 | a | 0 | a | 0 | a | ||||
140 | 1 | ab | Z | 1 | ab | Z | 0 | ab | Z | 0 | ab | Z |
210 | 8 | bc | Z | 1 | ab | Z | 1 | ab | Z | 2 | bc | Z |
280 | 17 | cd | Y | 3 | b | YZ | 2 | b | Z | 5 | bc | YZ |
420 | 49 | d | Y | 5 | b | Z | 2 | b | Z | 12 | c | YZ |
aAbbreviations: WAE, weeks after crop emergence.
injury. Soltani et al. [
Small red Mexican bean and kidney bean densities were not reduced by any of the herbicide treatments compared to the control (
Sulfentrazone rate (g・ai・ha−1) | Adzuki Bean | Kidney Bean | Small Red Mexican Bean | White Bean | ||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
Plant Density | % | |||||||||||
0 | 100 | a | Z | 100 | a | Z | 100 | a | Z | 100 | a | Z |
140 | 96 | a | Z | 84 | a | Z | 92 | a | Z | 96 | ab | Z |
210 | 78 | ab | Z | 100 | a | Z | 91 | a | Z | 92 | ab | Z |
280 | 66 | b | Y | 98 | a | YZ | 99 | a | Z | 87 | ab | YZ |
420 | 49 | b | Y | 78 | a | YZ | 86 | a | Z | 72 | b | YZ |
Plant Height | % | |||||||||||
0 | 100 | a | Y | 100 | a | Z | 100 | a | Z | 100 | a | Z |
140 | 103 | a | Y | 102 | a | Z | 102 | a | Z | 95 | ab | Z |
210 | 98 | a | Y | 99 | a | Z | 101 | a | Z | 92 | ab | Z |
280 | 86 | ab | Y | 97 | a | Z | 99 | a | Z | 83 | bc | Z |
420 | 66 | b | X | 93 | a | YZ | 94 | a | Z | 71 | c | Y |
Yield | % | |||||||||||
0 | 100 | a | Y | 100 | a | YZ | 100 | a | Z | 100 | a | Z |
140 | 91 | ab | Y | 99 | a | YZ | 95 | a | Z | 92 | a | Z |
210 | 89 | ab | Y | 96 | a | YZ | 93 | a | Z | 90 | a | Z |
280 | 72 | b | Y | 89 | a | YZ | 83 | a | Z | 83 | ab | Z |
420 | 43 | c | Y | 87 | a | Z | 87 | a | Z | 71 | b | Z |
Shoot dry weight was not affected by sulfentrazone at 140 or 210 g・ai・ha−1 (
Shorter plant heights can cause reduced yield at harvest due to harvest losses at the cutter bar of the combine. Kidney bean and small red Mexican bean height were not reduced by any of the sulfentrazone rates evaluated (
Herbicide injury can cause delayed maturity of the crop which can cause seed damage from delayed harvest and storage problems. Delayed maturity is indicated by elevated seed moisture content. In this study, sulfentrazone at 140, 210 and 280 g・ai・ha−1 did not increase seed moisture content compared to the untreated control, but seed moisture was 1.2% higher for the beans treated with 420 g・ai・ha−1 (
In this study, kidney bean and small red Mexican bean demonstrated the highest tolerance to PRE applications of sulfentrazone; plant density, height, and yield were not affected at any of the rates evaluated, and there was an acceptable margin of crop safety for rates up to 280 g・ai・ha−1. White bean had the next best tolerance, with plant density and yield only affected at 420 g・ai・ha−1, and a narrow margin of crop safety at rates up to 210 g・ai・ha−1. Adzuki bean had the poorest tolerance of the market classes evaluated, with plant density and yield reduced by 280 and 420 g・ai・ha−1, and unacceptable injury at 210 g・ai・ha−1 and above. Based on these results, PRE applications of sulfentrazone are safe for kidney and small red Mexican bean production in Ontario.
Taziar, A.N., Soltani, N., Shropshire, C., Robinson, D.E., Long, M., Gillard, C.L. and Sikkema, P.H. (2016) Tolerance of Four Dry Bean Market Classes to Pre-Emergence Applications of Sulfentra- zone. American Journal of Plant Sciences, 7, 2248-2256. http://dx.doi.org/10.4236/ajps.2016.715198