Phytotoxicity of Bentazon to Woody and Herbaceous Landscape Plants

Abstract

Eight species of low-growing woody and herbaceous landscape plants were evaluated for tolerance to 1.1 or 2.2 kg a.i. bentazon/ha (plus a crop oil) applied over the top twice 7 days apart. Raphiolepis indica L. Lindl. `Alba' was the only species tolerant to bentazon in either of two experiments. Bentazon injury to Liriope muscari (Decne.) L.H. Bailey `Evergreen Giant' was minor (slight chlorosis) and would probably be tolerable under most landscape situations. Injury (primarily chlorosis/necrosis) to Carissa macrocarpa `Emerald Blanket', Juniperus horizontalis Moench `Bar Harbor', Pittosporum tobira (Thunb.) Ait. `Compacta Green', Trachelospermum asiaticum (Sie-bold & Zucc.) Nakai `Aslo', Ophiopogon japonicus (Thunb.) Ker-Gawl., and Hemerocallis × `Aztec Gold' was significant and therefore unacceptable. Chemical name used: 3-isopropyl-1H-2,1,3-benzothiadiazin-(4)-3H-one 2,2-dioxide (bentazon).