Wheat gluten meal inhibits germination and growth of broadleaf and grassy weeds

The herbicidal activity of wheat gluten meal (WGM) was evaluated on 17 spec ies of monocotyledons and dicotyledons. Treatments included WGM at 0, 1, 2, 3, 4, 6, and 9 g.dm(-2). Germination, shoot and root lengths, and root num bers were recorded, Treatments reduced germination and root extension in ne arly all species. Leafy spurge (Euphorbia esula L.), redroot pigweed (Amara nthus retroflexus L.), shepherd's purse Capsella bursa-pastoris (L,) Medik. ], henbit (Lamium amplexicaule L,), quackgrass [Agropyron repens (L,) Beauv ,], annual bluegrass (Poa annua L.), Canada thistle [Cirsium arvense (L,) S cop,], orchardgrass (Dactylis glomerata L.), purslane (Portulaca oleracea L ,), annual ryegrass (Lolium multiflorum Lam,), and snap bean (Phaseolus vul garis L.) were particularly sensitive. Germination of curly dock (Rumex cri spus L,) and common lambsquarters (Chenopodium album L,) was suppressed at the higher rates. Germination of black medic (Medicago lupulina L.), spotte d knapweed (Centaurea maculosa Lam.), mustard (Brassica sp,), and corn (Zea mays L.) were not substantially affected at any rate. Shoot growth of all species was inhibited at rates >2 g . dm(-2), and at the highest rates no s hoots developed. In nine species, shoot extension was stimulated at 1 g . d m(-2) WGM, The herbicidal activity of WGM was not due to a "mulching" effec t, since growth characteristics were also altered in bean seeds barely cove red by the treatments.