Effect of barnyard grass (Echinochloa spp) on paddy rice (Oryza sativa L.) yield in Chile

Juan Ormeño N.1

Yields and barnyard grass (Echinochloa spp) dry maller production data obtained from 12 lield control trials conducted over three crop seasons were used for assessing and estimating crop losses in Ilooded rice (Oryza sativa L.). Comparing untreated plots with the best chemical control, it was concluded that barnyard grass control was 93.9% etticient, ranging from 84.9 to 99.1 %, although erratic control levels of Echinochloa crus-galli and E. oryzoides, the two most important barnyard grass species of rice in Chile, were also detected with the standard granular molinate. Average yield reductions were 27.3 qqm/ha or 36.4% less it adequate control measures were taken. For the entire rice producing area of the country (36,700 ha), an annual loss of US $ 9.9 millions due to barnyard grass infestations was estimated.

Keywords: weed competition, flooded rice, barnyard grass, Echinochloa crus-galli, Echinochloa oryzoides, economic losses.
1 Estación Experimental La Platina (INIA), Casilla 439, Correo 3, Santiago. Chile.