Ethalfluralin has been reported to be a more active herbicide than trifluralin . Ethalfluralin and trifluralin co-applied with halosulfuron can provide effective broad-spectrum control of common annual grass and broadleaf weeds in white bean production in Ontario. However, limited information is available on comparing the efficacy of trifluralin and ethalfluralin applied alone and in combination with halosulfuron for weed management in white bean under Ontario environmental conditions. The purpose of this study was to compare the efficacy of trifluralin and ethalfluralin applied alone and in combination with halosulfuron, applied PPI, on white bean tolerance and yield, and weed control efficacy. The GLIMMIX procedure in SAS was utilized for data analysis, with herbicide treatment as the fixed effect and year-location combinations, replicate within environment and environment by treatment interaction as the random effects. Potential distributions were assessed using residual plots,grow lights for cannabis fit statistics and the Shapiro-Wilk statistic to find the most appropriate distribution or transformation. Analysis was performed on the model scale, with least square means presented on the data scale.
Treatment differences were determined at a significance level of 0.05, after pairwise comparisons were subjected to Tukey’s adjustment. The Gaussian distribution and identity link were used for percent control of velvetleaf , wild mustard , white bean moisture at harvest and yield. All other percent weed control data were arcsine square-root transformed prior to analysis, and back-transformed for presentation. Treatments with zero variance were excluded from the analysis and included the weedy control and the weed-free control for percent weed control. Comparisons of each treatment with the value zero were still conducted and differences identified using the P values from the LSMEANS output. At 2, 4 and 8 WAE, there was no white bean injury from the herbicide treatments evaluated . There was a delay in white bean maturity due to weed interference as indicated by increased seed moisture content at harvest . Weeds interference decreased white bean seed yield 72% . Generally, white bean yield reflected the level of weed control provided by the herbicide treatments evaluated. There was no difference in white bean seed yield between trifluralin and ethalfluralin. Weed presence decreased seed yield 44% – 45% with trifluralin and 30% – 41% with ethalfluralin .
Weed interference with halosulfuron applied alone decreased seed yield 34% . In contrast, decreased weed interference with trifluralin and ethalfluralin applied in combination with halosulfuron resulted in white bean seed yield that was similar to the weed-free control. These results are similar to other studies that have shown little white bean injury with trifluralin and trifluralin + halosulfuron in white bean. Soltani et al. 2014 found no injury with trifluralin applied PPI alone and 1% injury with trifluralin + halosulfuron applied PPI in white bean . In other studies, grow cannabis halosulfuron, applied PPI was shown to be safe for use on most market classes of dry beans except for azuki, mung, and snap bean In another study, halosulfuron caused 8% injury and reduced seed yield 7% in snap bean . Many economically important weeds of field crops spread via perennating organs such as stolons, rhizomes, tubers, bulbs, or corms. Substrates of nursery container crops are isolated from each container, thus weeds cannot spread via perennating organs as they do in field soils. Weeds of nursery container crops spread primarily by seed dispersal.
The most common method of weed control in nursery container crops is the use of pre-emergence herbicides applied to the substrate surface to inhibit weed establishment from seed. However, some crops such as hydrangea Ser., azalea Planch., and many herbaceous perennials are sensitive to pre-emergence herbicides , and no pre-emergence herbicide is currently labeled for use on container crops inside enclosed structures such as greenhouses. The most common alternative to herbicides is the use of mulches. Numerous mulch products have been evaluated in container crops . Pine bark nuggets have been shown to provide effective control of mulberry weed Nakai , prostrate spurge , eclipta bitter cress , and oxalis In each of the aforementioned studies, weed control was shown to improve with increasing depth of pine bark mulch. Wilen et al. showed that composted green waste, pecan K. Koch shells, and pine bark at a depth of 2.5 cm provided excellent control of creeping wood sorrel , northern willow herb , and common groundsel , but only moderate to poor control of annual bluegrass .