Soy desiccants herbicides acting in nematode populations on community land

Abstract

The use of herbicides is the main method of weed control in soybeans. Desiccants are also being used routinely to anticipate the harvest and / or minimize the deterioration of seed quality. There is the possibility of direct or indirect contact with such pesticides, affect the community of nematodes in the soil. However, such effects and their magnitudes are yet to be clarified, especially in the case of selective herbicides. Thus, the objective of this study was to evaluate the use of selective herbicides in soybean on nematodes harmful to the crop. The experiment was conducted with transgenic soybean (‘M-SOY 7908RR’). The experimental design was a randomized block design with the following treatments: paraquat (400 g a.i ha-1), diquat (200 g a.i ha-1), a mixture of paraquat and diquat (300 + 150 g a.i ha-1), two doses of carfentrazone ethyl (20 g a.i ha-1 and 30 g a.i ha-1) and control (without desiccant application). The nematode community in the area was monitored in four periods. In none of those was found significant variation in the populations of nematodes harmful to soybeans, due to the application of any of desiccants. However, especially in the last sampling time, the desiccant application always resulted in increased populations of free-living nematodes and parasites those considered weak for soybean.