Mixtures For Weed Control in Newly Planted Loblolly Pine (Pinus taeda L.)
Imazapyr, metsulfuron methyl, imazapyr plus metsulfuron methyl, and hexazinone plus metsulfuron methyl were aerially applied over newly planted and 1-year-old loblolly pine seedlings for the control of blackberry (Rubus species), composites (Compositae), sumac (Rhus copallina L.), and trumpet vine [Campsis radicans (L.) Seemann]. The study was installed at three locations with three replications of each treatment at each location. Imazapyr (0.375 lbs ai/A) plus metsulfuron methyl (0.063 lbs ai/A) gave the best control of sumac, blackberry, composites, and trumpet vine for 4 months after treatment. There appeared to be some synergism in the imazapyr plus metsulfuron methyl mixture against blackberry and sumac, but antagonism in the mixture of hexazinone (0.5 lbs ai/A) plus metsulfuron methyl (0.063 lbs ai/A) against blackberry. Loblolly pine seedling survival was not affected by any of the treatments tested. Minimal pine seedling damage was observed on newly planted seedlings treated with imazapyr at 0.375 lbs ai/A.