Two trials were conducted for efficiency of spray-deposit distribution and for insect control in soybean crop in Uruguay. In the first one the effects of droplet size, volume application rate and application time in the control of bean shoot borer (Epinotia aporemai W.) were evaluated. The second trial consisted in evaluating the effects of droplet size and application speed in the control of shield bugs (Nezara viridula L. and Piezodorus guildinii W.). Distribution of a fluorescent dye was evaluated by counting impact on the foliage in the middle and upper canopy. Impact density was higher with fine and medium compared to very coarse droplets on the upper side of the leaves in both trials, but on the inner side, impact density was similar among the three evaluated droplet sizes. Increasing application speed decreased impact density, particularly at the middle height of the foliage. At this height, impact on the underside of leaves was extremely low. Insect control was higher in treated than untreated plots, however, different droplet size, speed and application time resulted in similar control. The results emphasize convenience of very large and medium droplets in the control of insects in soybean due to its efficacy and drift potential reduction.
shield bugs; bud shoot borer; droplet size; application speed
