Efficacy of Preemergence Herbicides for Controlling a Dinitroaniline-Resistant Goosegrass (Eleusine indica) in Georgia

Abstract

[EN] Goosegrass is a problematic weed in turfgrass, and overuse of dinitroaniline (dna) herbicides has resulted in evolution of resistant populations. The objectives of this research were to (1) evaluate responses of a susceptible (S) goosegrass compared to a suspected resistant (R) biotype from Griffin, GA to prodiamine, and (2) evaluate efficacy of various PRE herbicides for control. Prodiamine rates required for 50 % control and 50 % shoot reductions after 6 wk for R-goosegrass measured > 13.44 and 3.2 kg ai ha(-1), respectively, whereas rates for the S-population measured 0.45 and < 0.42 kg ha(-1), respectively. In field experiments, sequential applications of dithiopyr and prodiamine provided < 20 % control of R-goosegrass over 2 yr. Single applications of dimethenamid-P at 1.68 kg ai ha(-1) provided < 50 % goosegrass control in 2011 but provided excellent control (>= 90%) at 7 mo after initial treatments (MAIT) in 2012. Single and sequential applications of indaziflam provided excellent control of goosegrass in both years, and oxadiazon controlled goosegrass > 85% at 7 MAIT in 2011 and >= 90% in 2012. Single and sequential PRE sulfentrazone applications controlled goosegrass < 60% in 2011 but averaged 94% control in 2012. Overall, indaziflam and oxadiazon provided good (80 to 89%) to excellent control of dna-resistant goosegrass in both years, but dimethenamid and sulfentrazone were inconsistent. Nomenclature: Dimethenamid, dithiopyr, indaziflam, oxadiazon, prodiamine, sulfentrazone; goosegrass, Eleusine indica (L.) Gaertn.

[ES] Eleusine indica es una maleza problema´tica en cespedes, y el sobreuso de herbicidas dinitroaniline (dna) ha resultado en la evolucion de poblaciones resistentes. Los objetivos de esta investigaci ´ on fueron (1) evaluar la respuesta a prodiamine de un biotipo de E. indica susceptible (S) y un biotipo supuestamente resistente (R) proveniente de Griffin, GA, y (2) evaluar la eficacia de varios herbicidas PRE para su control. Las dosis de prodiamine requeridas para alcanzar 50% de control y reducciones del 50% del tejido aereo despu ´ es de 6 semanas para ´ E. indica-R fueron .13.44 y 3.2 kg ai ha1 , respectivamente, mientras que para E. indica-S fueron 0.45 y ,0.42 kg ha1 , respectivamente. En experimentos de campo, las aplicaciones secuenciales de dithiopyr y prodiamine brindaron ,20% de control de E. indica-R durante 2 anos. ˜ Aplicaciones de solo dimethenamid-P a 1.68 kg ai ha1 brindaron ,50% de control de E. indica en 2011, pero en 2012, brindaron control excelente (90%) a 7 meses del tratamiento inicial (MAIT). Aplicaciones solas y secuenciales de indaziflam brindaron un control excelente de E. indica en ambos anos, y oxadiazon control ˜ o´ .85% a 7 MAIT en 2011 y 90% en 2012. Aplicaciones PRE solas y secuenciales de sulfentrazone controlaron ,60% en 2011, pero promediaron 94% de control en 2012. En general, indaziflam y oxadiazon brindaron un control de bueno (80 a 89%) a excelente de E. indica resistente a dna en ambos anos, mientras el control con dimethenamid y sulfentrazone fue inconsistente.