Two experiments were established in Los

Naranjos, Veracruz, México to evaluate the weed control

efficacy of the postemergence herbicide bispyribac-sodium,

alone and in mixture with other herbicides in rainfed rice and

to evaluate the toxicity of bispyribac-sodium to rice. An

experiment was established on June 13, 1999, and the second

on June 9, 2000 with rice cv Milagro Filipino at 100 kg/ha. A

randomized complete block design with eight treatments and

the second six with four replication each one was established.

In 1999, weed control was evaluated at 15, 30 and 105 days

after application (DAA) and in 2000, at 15, 30 and 45 DAA.

In both experiments, toxicity was evaluated at 15 and 30

DAA. The main weed species were junglerice [Echinochloa

colona (L.) Link.], flatsedge (Cyperus iria L.) and Southern

crabgrass [Digitaria ciliaris (Retz.) Koel]. Bispyribacsodium

affected only emerged plants; this herbicide

efficiently controlled flatsedge at 15 g/ha, junglerice at 22

g/ha and Southern crabgrass was only partially controlled.

When bispyribac-sodium was mixed with clomazone or

thiobencarb, grass control was increased and a residual

herbicide effect was obtained. Bispyribac-sodium was highly

selective to rice.