Chemical weed control in peas

Abstract

Several herbicides were evaluated in direct-seeded and transplanted sweet and red peppers under sprinkler and furrow irrigation. In pre-emergence (direct-seeded) trials the herbicides were applied after sowing and incorporated into the soil by sprinkler irrigation. Diphenamid at 4-8 Ib./acre gave complete control of grasses and excellent control of broad-leaved weeds. Benefin at 4 Ib./acre and Trifluralin at 2 Ib./acre also gave excellent control of both types of weed. Vegadex gave moderately good control of broad-leaved weeds but was ineffective against grasses. Pepper seedling emergence was not affected, but some foliage yellowing and slightly reduced vigour were evident 6 weeks after sowing. These effects did not, however, persist during the phase of rapid growth. In post-emergence trials several herbicides were applied in the furrows (after clean cultivation) one to 3 months after transplanting and incorporated by furrow irrigation. Benefin, CIPC, Treflan, Vegadex and Vegiben gave good control of weeds during the early part of the season, but later on the weeds were generally vigourous enough to interfere with harvesting. With Diphenamid, however, weeds did not develop extensively and the furrows remained free of large weeds throughout the summer. In further pre-emergence trials Diphenamid at 2 and 4 Ib./acre, followed by sprinkler irrigation, effectively controlled broad-leaved weeds and grasses but caused some injury to the pepper seedlings. The experimental compound R.7465 gave equally good weed control, but injury was noticeable under both irrigation methods.- Univ. Calif., Riverside.