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Abstract: Saflufenacil is a new herbicide for broadleaf weed control in various crops. In rice, saflufenacil can be a prospective combination partner to complement the broadleaf weed control of herbicides such as imazethapyr. This study was established to evaluate 1) rice tolerance and 2) weed control of red rice (Oryza sativa L.) and hemp sesbania (Sesbania exaltata P. Mill.) to saflufenacil tank-mixed with imazethapyr. The experiment was conducted during 2009 and 2010 at the Texas A&M AgriLife Research and Extension Center located at Beaumont, TX. Treatments included a check, an imazethapyr treatment alone (70 g a.i. ha−1 at the 1- to 2-leaf stage (EPOST) plus 70 g a.i. ha−1 at the 4- to 6-leaf stage (LPOST)), and four saflufenacil doses (12.5, 18.75, 25, and 50 g a.i. ha−1) applied at EPOST and LPOST. Imazethapyr treatment was applied to all saflufenacil treatments. Rice injury increased with doses of saflufenacil and injury up to 83% was observed at 7 DAA when 50 g ha−1 was applied EPOST. Subsequent evaluations indicated less injury over time demonstrating rice recovery from saflufenacil treatments. No injury was observed in the imazethapyr treatment alone. Rice plants seemed to recover faster from LPOST application injury than EPOST. Hemp sesbania control was ≥88% in all saflufenacil treatments in evaluations conducted before harvest indicating effective control throughout the growing season. Red rice control was 100% for all treated plots containing imazethapyr in both years. Therefore, imazethapyr control of red rice was not adversely affected by tank-mixing with saflufenacil. Although injury was significantly higher in the highest doses of saflufenacil, rice yield was not adversely altered by the herbicide treatments. In summary, rice was injured at the highest doses of saflufenacil, but injury did not reduce rice yield. Hemp sesbania was effectively controlled by saflufenacil (>90% on average). No antagonistic interactions between saflufenacil and imazethapyr were observed with red rice control. Saflufenacil appears to be an effective herbicide candidate for broadleaf control in rice. [Copyright &y& Elsevier]

The herbicides imazethapyr and imazapic, used in Clearfield® rice, have high mobility and persistence in the soil, causing injury to non-resistant rice grown in rotation. These herbicides can leach and reach greater depths along the profile. This positioning can be a in-depth selectivity factor and partially explain the different results found in literature about carryover of imidazolines. To understand this effect, this study had the objective of to evaluate the effect of the positioning of the mixture of imazethapyr and imazapic (75g ai L-1 and 25g ai L-1) on the injury to non-resistant rice crop. Two experiments were carried out in soil with 15% clay and 1.2% organic matter in a greenhouse at the Universidade Federal de Pelotas, Pelotas, RS, Brazil. Experiment I consisted of a preliminary study to verify the location depth of the herbicide in the soil profile that causes injury to rice non-tolerant rice, and the herbicides has been allocated at depths of 0, 5, 10, 20, 30, 50 e 70cm. Experiment II also consisted in the allocation of herbicide at depths in the soil profile of 3, 6, 9, 12, 15 and 18cm. The variables were visual plant injury, plant shoot dry weight and plant height. The formulated mixture of imazethapyr + imazapic located near the soil surface cause injury to non resistant rice plants but when allocated at depths greater than 20cm of the soil surface does not affect the development of non-resistant rice . [ABSTRACT FROM AUTHOR]