Dry bean (Phaseolus vulgaris L.) is a high value leguminous crop with nitrogen fixation ability that Ontario growers often use in rotation with wheat (Triticum aestivum L.), field corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] to break pest cycles and improve soil fertility. In 2014, dry bean growers planted nearly 53,000 hectares and produced 130,000 MT of dry bean with a farm gate value of approximately $100,000,000 [1] . Major market classes (different geographic origin, gene pool, seed size and seed color) of dry bean grown in Ontario include black, cranberry, kidney and white (navy) bean. Intensive agronomic practices, including proper weed management and plant nutrition, are needed for profitable dry bean production.

In recent years, biostimulants have been marketed by agricultural products companies for enhancing crop growth and yield of various crops. Biostimulants are generally referred to as compounds, substances and other products that can enhance plant growth and development by increasing the efficiency of physiological process within plants when applied in small quantities to plants or soils [2] [3] . These products can include microorganisms, trace elements, enzymes or plant growth regulators [2] [3] . Biostimulant global market is projected to grow 12.5% annually and reach US$ 2241 million by 2018 [3] . Research has shown the ability of some biostimulants to enhance crop efficiency, increase nutrient availability, increase water-holding capacity, increase antioxidants, enhance metabolism and increase chlorophyll production in plants [3] -[10] . Hanson [7] found significant increases in yield of vegetable crops with biostimulants. Al-Majathoub [10] found as much as 21% increase in tiller numbers and as much as 8.2% increase in wheat yield with biostimulants.

Crop Booster and RR SoyBooster are two biostimulants marketed by Axter Agrosciences Inc. for enhancing vigor and foliage development in fruits, vegetables and field crops in Ontario [11] -[13] . Crop Booster contains 15% total nitrogen, 3% phosphoric acid (P₂O₅), 6% soluble potash (K₂O), 0.02% boron, 0.05% chelated manganese, 0.05% molybdenum, 0.05% chelated zinc, and 0.5% E.D.T.A. (chelating agent) [12] . RR SoyBooster composition is exactly the same as Crop Booster except for its total nitrogen which is 6% and available phosphoric acid (P₂O₅) which is 18% [13] .

According to the Axter Agrosciences Inc., Crop Booster enables plants to produce the enzymes and organic acid needed to combat stress and compensate for plant’s inability to take up nutrients from the soil during periods of crop stress [11] . Crop Booster is also promoted as a biostimulant that works synergistically with herbicides to decrease crop stress that may be caused by the use of postemergence herbicides [11] .

Dry bean growers need information on the effect of biostimulants such as Crop Booster and RR SoyBooster on crop growth, development and weed control to make informed decisions on their use in order to maximize farm profitability as the demand on growers to minimize per unit cost of production is increasing to remain competitive in the global market. Lack of information or incorrect information about biostimulants may lead to unnecessary expenditures, and/or costly risk of failures in crop production including unnecessary loading of chemicals in the environment.

There is little information on the effects of the co-application of Crop Booster or RR SoyBooster with quizalofop-p-ethyl, bentazon, fomesafen, bentazon plus fomesafen, imazethapyr and imazethapyr plus bentazon in cranberry and white bean under Ontario environmental conditions.

The objective of this study was to evaluate if there was any benefit of adding Crop Booster or RR SoyBooster to postemergence herbicides that were commonly used for weed management in white and cranberry bean.

There were a total of 12 field experiments (6 in cranberry bean “Etna” and 6 in white bean “OAC REX”) conducted during 2006 to 2008 at the Huron Research Station, Exeter, Ontario and University of Guelph Ridgetown Campus, Ridgetown, Ontario. The soil type at Exeter was a Brookston clay loam soil and at Ridgetown was a Brookston loam soil. Seedbed preparation at all sites consisted of fall moldboard plowing followed by two passes with a field cultivator with rolling basket harrows in the spring.

Field trials were established as a randomized complete block design with four replications. Treatments are listed in Tables 1-12 for white bean and cranberry trials. Plots consisted of two rows of cranberry bean (“Etna”) or white bean (“OAC REX”) that were spaced 0.75 m apart and were 10 m long at Exeter and 8 m long at Ridgetown. Beans were planted in late May to early June of each year. Dry beans were fertilized according to provincial recommendations [1] . Dry beans are not generally irrigated in Ontario.

Herbicide treatments were applied with a CO₂-pressurized back-pack sprayer equipped with Hypro ULD120- 02 nozzle tips (Hypro, New Brighton, MN) calibrated to deliver 200 L∙ha⁻¹ of water at 200 kPa. Herbicide applications were made with a 2.5 m boom with six nozzles spaced 50 cm apart. Treatments were applied when the beans were in the 1 - 3 trifoliate leaf stage. All plots were maintained weed-free during the season with hand

^aSignificance of contrasts comparing quizalofop-p-ethyl alone with quizalofop-p-ethyl plus either Crop Booster or RR SoyBooster denoted by ^* for P < 0.10 and ^**for P < 0.05 beside the respective mean. ^bSure-mix added to all herbicide treatments at 0.5% v/v.

^aSignificance of contrasts comparing quizalofop-p-ethyl alone with quizalofop-p-ethyl plus either Crop Booster or RR SoyBooster denoted by ^* for P < 0.10 and ^**for P < 0.05 beside the respective mean. ^bSure-mix added to all herbicide treatments at 0.5% v/v.

^aSignificance of contrasts comparing bentazon alone with bentazon plus either Crop Booster or RR SoyBooster denoted by ^*for P < 0.10 and ^**for P < 0.05 beside the respective mean.

hoeing and cultivation as required.

Estimate of crop injury was evaluated visually 1, 2 and 4 weeks after treatment (WAT) using a scale of 0 to 100% where a rating of 0 was defined as no visible plant injury and a rating of 100 was defined as plant death.

^aSignificance of contrasts comparing bentazon alone with bentazon plus either Crop Booster or RR SoyBooster denoted by ^*for P < 0.10 and ^**for P < 0.05 beside the respective mean.

^aSignificance of contrasts comparing fomesafen alone with fomesafen plus either Crop Booster or RR SoyBooster denoted by ^*for P < 0.10 and ^**for P < 0.05 beside the respective mean. ^bTurbocharge added to all herbicide treatments at 0.5% v/v.

^aSignificance of contrasts comparing fomesafen alone with fomesafen plus either Crop Booster or RR SoyBooster denoted by ^*for P < 0.10 and ^**for P < 0.05 beside the respective mean. ^bTurbocharge added to all herbicide treatments at 0.5% v/v.

At 4 WAT, a 1 m section of row for each cultivar was hand harvested at the ground level, oven dried at 60˚C to constant moisture and the shoot dry weight was recorded. Ten plants per plot were randomly selected and the height from the soil surface to the highest growing point was measured 6 WAT. Yield and seed moisture content were measured at crop maturity by combining the remaining 9 m from each plot at Exeter and 7 m from each plot at Ridgetown. Crops were considered physically mature when 90% of pods in the untreated plots of each

^aSignificance of contrasts comparing bentazon + fomesafen alone with bentazon + fomesafen plus either Crop Booster or RR SoyBooster denoted by ^*for P < 0.10 and ^**for P < 0.05 beside the respective mean.

^aSignificance of contrasts comparing bentazon + fomesafen alone with bentazon + fomesafen plus either Crop Booster or RR SoyBooster denoted by ^*for P < 0.10 and ^**for P < 0.05 beside the respective mean.

^aSignificance of contrasts comparing imazethapyr alone with imazethapyr plus either Crop Booster or RR SoyBooster denoted by ^*for P < 0.10 and ^**for P < 0.05 beside the respective mean. ^bAgral 90 added to all herbicide treatments at 0.25% v/v.

cultivar had turned from green to a golden colour. All yields were adjusted to 18% moisture.

Data for each market class of dry bean (cranberry and white bean) were analyzed as an RCBD using PROC MIXED in SAS 9.2. Herbicide treatment was considered a fixed effect, while environment (year-location combinations), the interaction between environment and herbicide treatment, and replicate nested within environment were considered random effects. Significance of the fixed effect was tested using F-test and random effects were tested using a Z-test of the variance estimate. The UNIVARIATE procedure was used to test data for normality and homogeneity of variance. The untreated check (for injury ratings) was excluded from the analysis. To

^aSignificance of contrasts comparing imazethapyr alone with imazethapyr plus either Crop Booster or RR SoyBooster denoted by ^*for P < 0.10 and ^**for P < 0.05 beside the respecitive mean. ^bAgral 90 added to all herbicide treatments at 0.25% v/v.

^aSignificance of contrasts comparing Pursuit + bentazon alone with Pursuit + bentazon plus either Crop Booster or RR SoyBooster denoted by ^*for P < 0.10 and ^**for P < 0.05 beside the respective mean.

^aSignificance of contrasts comparing imazethapyr + bentazon alone with imazethapyr + bentazon plus either Crop Booster or RR SoyBooster denoted by ^*for P < 0.10 and ^**for P < 0.05 beside the respective mean.

meet assumptions of normality, all injury (except cranberry bean at 4 WAT) were square root transformed; shoot dry weight and seed moisture content were log transformed. Contrasts were used to compare each herbicide versus the same herbicide plus Crop Booster or RR SoyBooster. Data compared on the transformed scale were converted back to the original scale for presentation of results. The Type I error was set at P < 0.05 for all statistical comparisons.

Based on these results, there was no increase in visible injury with the addition of Crop Booster or RR SoyBooster to quizalofop-p-ethyl, bentazon, fomesafen, bentazon plus fomesafen, imazethapyr and imazethapyr plus bentazon in cranberry and white bean under Ontario environmental conditions. The addition of Crop Booster or RR SoyBooster to quizalofop-p-ethyl, bentazon, fomesafen, bentazon plus fomesafen, imazethapyr and imazethapyr plus bentazon generally had no effect on shoot dry weight, plant height, seed moisture content of cranberry or white bean. In many comparisons, there was a small numeric increase in yield of white and cranberry bean with the addition of Crop Booster or RR SoyBooster to quizalofop-p-ethyl, bentazon, fomesafen and bentazon plus fomesafen, but this increase in yield was not statistically significant at the P < 0.05 level.

The authors would like to acknowledge Todd Cowan for his expertise and technical assistance in these studies.

NaderSoltani,ChristyShropshire,Peter H.Sikkema, (2015) Responses of Dry Bean to Biostimulants Added to Postemergence Herbicides. Agricultural Sciences,06,1023-1032. doi: 10.4236/as.2015.69097

WAT: weeks after herbicide treatment.