Damage caused by corn rootworm in corn field conditions.

The aim of this study was to evaluate the damage caused by different larval densities of Diabrotica speciosa in maize BG 7060 H under field conditions. The experiment was conducted in the field in 2012/2013, at Embrapa Clima Temperado (31°S 52°W 49,268 and 27,472). Each plot consisted of six rows 5 m x 0.70 m and the cultivar used was BG 7060 H. The plants were infested with 5, 15, 30 and 40 larvae/plant, and there was a control (no larvae). The damage, weight and length of roots were evaluated 64 days after infestation (DAI) (22/01/2013). At the harvest, plant and ear height and yield were evaluated. No significant reduction in the weight of roots infested with larvae of beetles was observed. The root length was numerically higher when there was no larval infestation. Plant and ear height was not affected by the infestation. According to Iowa State 1-6 damage scale, regardless of of the number of larvae inoculated to roots, damages were below 2.0 (1.29 to 1.74). According to scale of Iowa 0-3, there was damage less to 0.75 (0.23 to 0.60). In relation to yield, it was observed that, in general, as increased larval density, there was a reduction in yield.