Control of Propanil-Resistant Barnyardgrass (Echinochloa crus-galli) in Rice (Oryza sativa) with Carbaryl/Propanil Mixtures

Abstract

Propanil and carbaryl mixtures, propanil formulated with carbaryl, the package mixture of propanil plus molinate (alone and plus pendimethalin), propanil plus quinclorac, and propanil plus pendimethalin were evaluated in field experiments for control of propanil-resistant and -susceptible barnyardgrass in 1995 and 1996 in Arkansas. Propanil alone at 3.3 kg ai/ha did not control propanil-resistant barnyardgrass when applied to two-leaf and repeated at four-leaf barnyardgrass. Propanil at 3.3 kg/ha with carbaryl at 0.1 to 0.3 kg ai/ha controlled propanil-resistant barnyardgrass at least 90% when applied at the two-leaf stage with no rice yield reduction. Applications repeated at the four-leaf stage also controlled propanil-resistant barnyardgrass, but rice injury was 66% with 0.3 kg/ha carbaryl in 1 of 2 yr, and rice yield was reduced. Control of resistant barnyardgrass with the commercial formulation of propanil plus carbaryl and propanil plus molinate was lower with a single application than with repeat applications. Propanil plus quinclorac, propanil plus pendimethalin, and propanil plus molinate plus pendimethalin controlled resistant barnyardgrass with one application at the two-leaf stage.