Author
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Vaughn, Steven |
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Palmquist, Debra |
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Duval, Sandra |
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Berhow, Mark |
Submitted to: Weed Science
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 3/21/2006 Publication Date: 7/17/2006 Citation: Vaughn, S.F., Palmquist, D.E., Duval, S.M., Berhow, M.A. 2006. Herbicidal activity of glucosinolate-containing seedmeals. Weed Science. 54(4):743-748. Interpretive Summary: Bioherbicides are plant biochemicals with pesticidal properties. Residual seedmeals from several plants which are grown primarily for their useful oils have been shown to act as bioherbicides due to biochemicals present in these seedmeals. In this paper we studied fifteen seedmeals for their ability to inhibit the germination and growth of weed seeds. We also identified the chemicals primarily responsible for this activity. Our results suggest that several of these seedmeals may be useful as bioherbicides not only for organic growers who cannot use synthetic herbicides but also for conventional growers as environmentally-friendly herbicides. Technical Abstract: Defatted seedmeals from fifteen glucosinolate-containing plant species were analyzed for bioherbicidal activity by determining inhibition of seedling emergence when added to a sandy loam soil containing wheat (Triticum aestivum L.) and sicklepod [Senna obtusifolia (L.) H. S. Irwin & Barneby] seeds at rates of 0.1, 0.5 and 1.0% (w/w). Added seedmeals were generally more phytotoxic to wheat than sicklepod seed germination. For wheat, all of the seedmeals significantly inhibited seedling emergence at the 1.0% level. At the 0.1% rate three of the seedmeals {brown mustard [Brassica juncea (L.) Czern.], money plant (Lunaria annua L.), and field pennycress (Thlaspi arvense L.)} completely inhibited wheat germination. For sicklepod germination, eight of the seedmeals were completely inhibitory at the 1% rate {brown mustard, field pennycress, arugula [Eruca vesicaria (L.) Cav. subsp. sativa (Mill.) Thell.], Siberian wallflower (Erysimum x allionii), English wallflower [Erysimum cheiri (L.) Crantz], garden cress (Lepidium sativum L.), sweet alyssum [Lobularia maritima (L.) Desv.] and evening-scented stock [Matthiola longipetala (Vent.) DC.]} and four were completely inhibitory at the 0.5% rate (brown mustard, arugula, English wallflower and sweet alyssum). Intact glucosinolates and their corresponding hydrolysis products varied among the seedmeals with the highest activity. Major hydrolysis products produced by the seedmeals with the most phytotoxicity, respectively, included 2-propenyl (allyl) isothiocyanate (AITC) by brown mustard seedmeal, allyl thiocyanate and AITC by field pennycress seedmeal, erucin (4-methylthiobutyl isothiocyanate) by arugula seedmeal, 3-butenyl isothiocyanate and lesquerellin (6-methylthiohexyl isothiocyanate) by sweet alyssum seedmeal, and isopropyl isothiocyanate by money plant seedmeal. |