engleski

Sugar beet (Beta vulgaris L.) response to simulated mesotrione residues

Mesotrione is a p-hydroxyphenylpyruvate dioxygenase (HPPD) inhibiting triketone herbicide that indirectly inhibits carotenoid production in susceptible plants. Although defined as non-persistent, several studies have shown that one year after mesotrione application in a corn field, its residue can damage sensitive crops grown in rotation. The aim of this study was to determine the susceptibility of sugar beet to simulated mesotrione residues in two different soils: (1) hipogley and (2) humofluvisol. Symptoms of phytotoxicity (bleaching) were assessed at 7, 14 and 21 days after application (DAA) by using a 0 to 100% scale (where 0 = no effect and 100 = plant death). The fresh weight of sugar beet was determined on the 21st day, after which the total carotenoid content was determined by spectrophotometry. The highest visually evaluated phytotoxicity on both soils was determined on the 21 DAA. On humofluvisol, damages were noticed already at the lowest dose (0.25 μg a.i. per 200 g soil). The sugar beet plants were completely damaged at 4 μg a.i. on humofluvisol and at 6 μg a.i. on hipogley soil. The effective dose (ED50) of mesotrione for 50% reduction of sugar beet fresh weight was 1.45 µg ml-1 on hipogley and 1.13 µg ml-1 on humofluvisol. The ED50 for 50% reduction of total carotenoids was 1.14 µg ml-1 on hipogley and 0.47 µg ml-1 on humofluvisol. These results indicated that soil type is very important factor in the response of sugar beet to mesotrione.

mesotrione ; sugar beet ; simulated residue carryover ; phytotoxicity

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