PHYSIOLOGICAL EFFECT OF THE INSECTICIDE THIAMETHOXAM ON SUGARCANE

ABSTRACT With the purpose to evaluate the physiological effect of thiamethoxam on the initial development of sugarcane, two experiments were carried out. In the first, carried out in Gerbox-type plastic boxes (3.5 x 11 x 11 cm) containing substrate, thiamethoxam was applied on sugarcane cuttings at the doses of 0, 100, 150 and 200 g of active ingredient per hectare (a.i.ha-1). The second experiment was carried in PVC pipes (0.2 x 1.20 m), filled with soil. Six doses of thiamethoxam (0, 50, 100, 150, 200 and 250 g a.i.ha -1) were used on two cultivars (RB867515 and SP80-1816).Roots and shoots were evaluated 30 days after the insecticide application in the first experiment and after 130 days in the second one. In the first experiment it was observed that the height characteristics, diameter and dry mass of shoots did not change through the use of the insecticide on sugarcane cuttings, however, in the treatments with thiamethoxam there was an increase on roots dry mass up to 3.7 times more. In the second experiment, thiamethoxam increased the diameter of shoots and the root dry mass of RB867515 cultivar up 72.69%. However, the length of the root system and the shoot dry mass were not changed by insecticide application in seedlings.