Few weed management options are available for juneberry, which has limited the potential for this new crop. Field trials were initiated at three locations in North Dakota to evaluate efficacy and crop safety associated with chemical and physical weed control treatments applied just before or immediately after transplanting. All treatments except norflurazon and trifluralin provided at least 85% control of redroot pigweed, common lambsquarters, common purslane, and yellow foxtail for the duration of the trial at Absaraka, ND, during 2001. Stinkgrass weed control 8 wk after treatment (WAT) dropped to unacceptable levels (<85%) with all treatments except azafenidin at 0.5 kg ai/ ha, norflurazon, and oxyfluorfen at 1.1 kg ai/ha at Dawson, ND, during 2001. However, juneberry injury 4 WAT by azafenidin at 0.5 kg/ha, flumioxazin at both locations, or azafenidin at 0.34 kg/ha and oxyfluorfen at 1.1 kg ai/ha at Absaraka, ND, was greater than observed for plants within the physical treatments. Juneberry injury generally decreased with time, yet remained >20% at 8 WAT for azafenidin and flumioxazin at Absaraka, ND, and for all treatments except the mulches at Dawson, ND. Plant injury 8 WAT at Absaraka in 2002 was 10% or less for all treatments and was lower compared with 2001. All physical treatments—azafenidin at 0.34 and 0.5 kg/ha, flumioxazin at 0.29 kg/ha, and oryzalin at 4.5 kg/ha—provided at least 85% control of all weed species at Carrington and Absaraka, ND, during 2002.
Nomenclature: Azafenidin, 2-;ob2,4-dichloro-5-(2-propynyloxy)phenyl;cb-5,6,7,8-tetrahydro-1,2,4-triazolo;ob4,3-a;cbpyridin-3(2H)-one; flumioxazin; oryzalin; oxyfluorfen, 2-chloro-1-(3-ethoxy-4-nitrophenoxy)-4-(trifluoromethyl)benzene; trifluralin; common lambsquarters, Chenopodium album L. #3 CHEAL; common purslane, Portulaca oleracea L. # POROL; redroot pigweed, Amaranthus retroflexus L. # AMARE; stinkgrass, Eragrostis cilianensis (All.) E. Mosher # ERACN; yellow foxtail, Setaria glauca (L.) Beauv. # SETLU; juneberry, Amelanchier alnifolia Nutt. ‘Lee 8’, ‘Martin’, ‘Smoky’.
Additional index words: Weed management, mulches, Saskatoon.
Abbreviations: MAT, months after treatment; WAT, weeks after treatment.