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ARS Home » Midwest Area » East Lansing, Michigan » Sugarbeet and Bean Research » Research » Publications at this Location » Publication #318932
Title: Preharvest herbicide treatments affect black bean desiccation, yield, and canned bean color

Author
item GOFFNETT, AMANDA - Michigan State University
item SPRAGUE, CHRISTY - Michigan State University
item MENDOZA, FERNANDO - Michigan State University
item Cichy, Karen

Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/15/2016
Publication Date: 6/1/2016
Citation: Goffnett, A., Sprague, C., Mendoza, F., Cichy, K.A. 2016. Preharvest herbicide treatments affect black bean desiccation, yield, and canned bean color. Crop Science. 56:1-8.

Interpretive Summary: Preharvest herbicides are frequently used by dry bean growers in Michigan as a harvest aid to desiccate weeds that may remain in the field, and to accelerate and promote uniform dry bean maturation. Preharvest herbicides have been shown to differ in effectiveness and speed of activity. Fast-acting herbicides, like paraquat, can result in complete foliar necrosis within 3 d. Slower-acting herbicides, like glyphosate, may take up to 15 d before plant death occurs. Depending on the herbicide, preharvest applications are typically labeled for use when dry bean seed moisture is = 30% or when at least 80% of beans pods are yellow. Applying preharvest herbicides prior to crop physiological maturity can have a negative impact on seed weight, seed germination, and yield and can lead to unacceptable herbicide residues in the harvested seed. Black bean processing quality may also be impacted by pre harvest herbicides, especially if applied early. The objective of this research was to evaluate the effect of preharvest herbicide treatments on the desiccation, yield, seed weight, seed germination, and canning quality and color of three black bean varieties. Three preharvest herbicide treatments, paraquat, glyphosate, and saflufenacil, were applied at a standard (pods = 80% yellow) application timing and an early application timing (pods = 50% yellow). A nontreated control was established for each variety. Differences in black bean desiccation were greatest 3 days after treatment, with paraquat and saflufenacil showing the quickest desiccation at the early application timing. By 7 days after treatment, desiccation for most preharvest treatments was over 95%. Saflufenacil applied at the early timing had the greatest impact on yield when compared with the nontreated control. Few differences in yield existed when preharvest herbicide treatments were applied at the standard application timing. Preharvest herbicide treatments only affected canned bean color when applied at the early application timing, with the greatest impact observed when glyphosate was applied at the early timing. Therefore, growers should be conscious of appropriate application timing and preharvest herbicide selection.

Technical Abstract: A field trial was conducted near Richville, Michigan in 2013 and 2014 to evaluate the effects of preharvest herbicide treatments on desiccation, yield, and canned black bean quality and color. Three Type II black bean varieties, Zorro, Eclipse, and Zenith, were planted on two different dates in each of two years. Three preharvest herbicide treatments, paraquat, glyphosate, and saflufenacil, were applied at a standard (pods = 80% yellow) application timing and an early application timing (pods = 50% yellow). A nontreated control was established for each variety. Differences in black bean desiccation were greatest 3 DAT, with paraquat and saflufenacil showing the quickest desiccation at the early application timing. By 7 DAT, desiccation for most preharvest treatments was over 95%. Saflufenacil applied at the early timing had the greatest impact on yield when compared with the nontreated control. Few differences in yield existed when preharvest herbicide treatments were applied at the standard application timing. Canned bean quality, including hydration coefficient, washed-drained coefficient, and texture, were usually only influenced by black bean variety and not preharvest herbicide treatments. Black bean varieties followed the same trend for color, where Zenith was the darkest, followed by Zorro, then Eclipse with the lightest color after canning. Preharvest herbicide treatments only affected color (L*, a*, and b* values) when applied at the early application timing, with the greatest impact observed when glyphosate was applied at the early timing. Therefore, growers should be conscious of appropriate application timing and preharvest herbicide selection.