Phytotoxicity in two sugarcane cultivars in the initial development as affected by selectivity to herbicides

Abstract

Sugarcane is a crop of great importance for human consumption, either for the production of sucrose or for the production of ethanol fuel. The objective of this work was to evaluate the phytotoxicity caused by the herbicides, the agronomic components in two sugarcane cultivars, at five evaluation times, during the 12-month and 18-month cultivation periods. The experimental design was randomized blocks with four replicates, in a 10 x 2 factorial scheme, with nine herbicides (tembotrione, mesotrione, clomazone, saflufenacil, 2,4 dichlorophenoxyacetic, fluroxypyr + picloram, metribuzin, isoxaflutole, sulfentrazone), two sugarcane cultivars (RB006995 and RB036153), and five evaluation times (7, 14, 21, 28 and 35 days after application – DAA). The most phytotoxic herbicides for the 12-month cultivation period in the cultivars RB036153 and RB006995 were clomazone and sulfentrazone. For 18-month cultivation period, the herbicides isoxaflutole, clomazone and sulfentrazone were the most phytotoxic, mainly for the cultivar RB006995. For most herbicides, phytotoxicity decreased along the days after application. The most selective herbicides for both cultivars and cultivation periods were tembotrione, mesotrione and fluroxypyr + picloram.

Spring-applied triclopyr mixtures for bermudagrass (Cynodon dactylon) suppression in Louisiana sugarcane

“…Necrotic sugarcane tissues from freezing air temperatures were mowed at the soil surface on February 28, 2018 andMarch 11, 2019 to encourage new growth. Each March sugarcane was off-bar cultivated as a standard practice, where front disks chop the row POST sugarcane tolerance has been reported for treatments that contained mesotrione, topramezone, pendimethalin, and triclopyr alone (Negrisoli et al 2019;Orgeron et al 2018;Perego et al 2020;Zandstra et al 2004); therefore, these treatments were applied once on April 1 and May 1, 2018 for EPOST and LPOST spring timings, respectively. In 2019 the EPOST application timing for treatments with mesotrione, topramezone, pendimethalin, and triclopyr alone was delayed until April 11 to ensure that the off-bar cultivation in early April did not reduce herbicide performance and to allow bermudagrass to recover before herbicide treatment, whereas in the same year, LPOST spring treatments were applied on May 2.…”