Revista Brasileira De Herbicidas 2014; 13(1): 23-30
Selectivity of residual herbicides and mixture with glyphosate applied after the pruning of cassava ‘Fécula Branca’
Cassava varieties (Manihot esculenta L. Crantz) intended for industrial starch manufacturers are usually pruned during the period of physiological rest of the plants, requiring the adoption of management practices to prevent weed competition in the second cycle of crop development. The objective was to evaluate the selectivity of pre-emergent herbicides applied alone or in tank mix with glyphosate in applications after pruning of cassava ‘Fécula Branca’. The experimental design was a randomized block with four replications. The treatments were: glyphosate (720 g ha-1), carfentrazone (25 g ha-1), chlorimuron-ethyl (10 g ha-1), clomazone (1,080 g ha-1), flumioxazin (83 g ha-1), metribuzin (480 g ha-1) metsulfuron-methyl (2.4 g ha-1), glyphosate + carfentrazone (720 + 25 g ha-1), glyphosate + chlorimuron-ethyl (720 + 10 g ha-1), glyphosate + clomazone (720 + 1080 g ha-1), glyphosate + flumioxazin (720 + 83 g ha-1), glyphosate + metribuzin (720 + 480 g ha-1), glyphosate + metsulfuron-methyl (720 + 2.4 g ha-1), and an untreated control. Evaluations included percentage of phytotoxicity, plant height, root yield and starch content of cassava. The herbicides applied alone and in tank mix did not cause phytotoxicity in cassava plants after application. The herbicides applied alone and in tank mix did not reduce plant height, root yield and starch content of cassava compared to untreated control. The isolated application of residual herbicides and mixes with glyphosate were considered selective when applied after pruning of cassava plants ‘Fécula Branca’.
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