RESPONSE OF WEEDS AND SEVERAL SHELTERBELT TREE AND SHRUB SPECIES TO GRANULAR SIMAZINE

Granular simazine (2-chloro-4,6-bis(ethylamino)-s-triazine), at 3.36, 6.72, and 10.08 kg/ha, was applied to new transplants of Caragana arborescens Lam., Cotoneaster acutifolia Turcz., Crataegus sp., Fraxinus pennsylvanica Marsh. var. subintegerrima (Vahl.) Fern., Hippophae rhamnoides L., Lonicera tatarica L., Malus baccata (L.) Borkh., Picea glauca (Moench) Voss, Picea pungens Engelm., Pinus sylvestris L., Populus deltoides Marsh., Populus × Northwest (Hort.), Prunus padus L. var. commutata Dipp., Prunus virginiana L. var. melanocarpa (A. Nels.) Sarg., Rosa rugosa Thunb. cult Hansa, Salix acutifolia Willd., Salix pentandra L., Shepherdia argentea Nutt., Sorbus americana Marsh., Syringa villosa Vahl., Ulmus americana L., and Ulmus pumila L. Simazine at 6.72 kg/ha gave 68% control of annual weeds and this was sufficient for the adequate growth of most of the tree and shrub species in this test. None of the species showed visible injury symptoms at any of the simazine rates tested, but the growth of some was reduced at the high simazine rate.