Acetanilide-Antidote Combinations for Weed Control in Corn (<i>Zea mays</i>) and Sorghum (<i>Sorghum bicolor</i>)

Abstract

R-25788 ( N,N -diallyl-2,2-dichloroacetamide) and H-31866 [ N -allyl- N -(3,3-dichloroallyl)dichloroacetamide] were more effective than CDAA ( N,N -diallyl-2-chloroacetamide) in preventing yield reductions to corn ( Zea mays L. ‘NB-611’) from alachlor [2-chloro-2′,6′-diethyl- N -(methoxymethyl)acetanilide] or metolachlor [2-chloro- N -(2-ethyl-6-methylphenyl)- N -(2-methoxy-1-methylethyl)acetamide] in the greenhouse. A CGA-43089 [α-(cyanomethoximino)-benzacetonitrile] seed treatment (1.25 g/kg) was more effective than a R-25788 tank mix in preventing yield reductions to grain sorghum [ Sorghum bicolor (L.) Moench ‘G-623 GBR’] from alachlor or metolachlor in the greenhouse. Absorption of 14 C-alachlor by sorghum seedlings grown in petri dishes, and absorption, translocation, and metabolism of 14 C-metolachlor by sorghum seedlings grown in soil, were not affected by CGA-43089 seed treatment. Forage sorghum [ Sorghum bicolor (L.) Moench ‘Rox Orange’] was used to simulate shatter cane [ Sorghum bicolor (L.) Moench] in field plots. In the absence of Rox Orange, alachlor and metolachlor reduced sorghum grain yields. This yield reduction was prevented by a CGA-43089 seed treatment, but not by a R-25788 tank mix with herbicides. In plots seeded with 10,000 Rox Orange seed/57 m 2 , grain yields of sorghum increased as alachlor or metolachlor plus CGA-43089 rates increased. There was no grain yield response to any herbicide treatment in plots seeded with 50,000 Rox Orange seed/57 m 2 .