1992

Herbicides and Plant Interference

AUBURN, Ala. - Herbaceous weed control has become an accepted practice by forest managers in the South. In the search for inexpensive and effective herbicides, considerable interest has been directed toward imazapyr, the latest herbicide registered for silvacultural purposes.

Imazapyr was tested through Alabama Agricultural Experiment Station research at four rates ( 0.1, 0.2, 0.4 and 0.8 pounds of active ingredient per acre), on three application dates (late fall, winter and early spring) and at eight locations (three planted to slash pine and five to loblolly pine).

Dean Gjerstad, professor of Forestry at Auburn University and project leader for the study, said that, though imazapyr suppressed height growth of slash pine (especially with early spring applications), little damage was detected for the late fall and early winter applications. These results indicate that imazapyr can be used safely on slash pine in preplant and site preparation situations.

Loblolly pine was more tolerant than slash pine to imazapyr, demonstrating no significant damage even at highest rates.

Weed control improved with increasing rates of imazapyr and spring applications provided better weed control than fall or winter applications. The herbicide provided excellent control on established Panicum spp. and also demonstrated that poor height growth occurred when herbicides were applied concurrent with a late-season planting of pine.

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News from:

Office of Ag Communications & Marketing

Auburn University College of Agriculture
Alabama Agricultural Experiment Station
3 Comer Hall, Auburn University
Auburn, AL 36849
334-844-4877 (PHONE) 334-844-5892 (FAX)

1992