Herbicide combinations for early post-emergence applications in direct-seeded rice

M. Azmi and M. A. Supaad

Abstract

Several herbicide combinations were tested in three consecutive season viz. off season 1987, main season 1987/88 and off season 1988 at the MARDI Research Station, Bumbong Lima, Seberang Perai. Similar dosages of herbicides were studied with varied time of post-emergence applications. The rate of each herbicide used In mixtures was lower than that recommended for singular applications. The efficacy of several herbicides applied in combination either as a tank-mix or proprietary mixture  as a broad spectrum weed control in direct seeded rice was determined. Propanil mixtures i.e. propane + molinate (at 1.0+ 2.0k g a.i./ha) and propanil + benthiocarb (at 1.0+ 1.5k g a.i./ha)a pplied8 days after sowing (DAS) were very effective against Echinochloa crus-galli. For a wide spectrum of control, quinclorac+ bensulfuron (at 0.25+ 0.03 kg a.i./ha) and molinate + 2,4-D IBE (at 2.5 + 0.75k g a.i./ha)a pplied1 0-14 DAS were the most effective herbicide mixtures. Quinclorac and molinate were effective against  E. crus-galli, where as bensulfuron and 2 ,4-D IBE were effective in controlling broadleaved weeds ands edges. Other promising herbicide mixtures include molinate+ bensulfuron (at 2.5 + 0.03 kg a.i./ha) and benthiocarb + pyrazosulfuron (at 2.0 + 0.01k g a.i./ha). No serious crop toxicity was caused by the herbicide mixtures tested except oxadiazon mixtures. All the herbicide combination-treated plots produced better yields compared with those of hand-weeded plots. The potential use of herbicide combinations is apparent as one of the better approaches for effective chemical weed control In direct-seeded rice.

Full Text (486 KB)