Edaphic Entomofauna Variation Depending on Glyphosate Application in Roundup Ready Soybean Crops

Abstract

Currently, biomonitoring is a methodology used to verify the environmental impact of new technologies in the agricultural environment, highlighting edaphic entomofauna that is traditionally used as a bioindicator in this sort of research. Therefore, the objective of this study was to investigate the edaphic entomofauna variation depending on glyphosate application in Roundup Ready soybeans. The experiment was carried out in Coimbra, MG during the 2007/2008 and 2008/2009 cropping seasons. The experimental design was a randomized block design with five replications. The treatments were: non-transgenic soybean with mechanical weeding of weeds; transgenic soybean with mechanical weeding of weeds; transgenic soybean with one glyphosate application and transgenic soybean with three glyphosate applications. The populations of the edaphic entomofauna were sampled during two crops. The insertion of the glyphosate tolerance gene did not affect the richness and the abundance of arthropods in the soil. The arthropod richness was reduced in treatments where glyphosate was applied one and three times. The glyphosate application in transgenic soybean reduced the density of the predatory mite Galumnidae (Acari); predator ants Neivamyrmex sp. (Hymenoptera: Formicidae) and Solenopsis sp. (Hymenoptera: Formicidae); and springtails Entomobryidae (Collembola), Hypogastrura sp. (Collembola: Hypogastruridae) and Onychiuridae (Collembola). Therefore, it is essential to follow the use recommendations of the herbicide glyphosate and adopt good agricultural practices that promote pesticide biodegradation, thereby contributing to the reduction of the toxicological potential of glyphosate on the edaphic entomofauna.

Study of the effects of glyphosate application on Collembola populations under controlled conditions

“…In Colombia, Arango and Macías (2004) identified only the family Entomobryidae in composters. Regarding population changes in Collembola, the results agree with field and laboratory tests in which this herbicide was used on springtail populations or species (Santos et al, 2010;Reimche, 2014;Al-Daikh et al, 2016;Mohammed et al, 2017;Vinod & Sanal-Kumar, 2017;Pereira et al, 2018) and other arthropods such as isopods, Neoptera, Coleoptera and spiders (Niemeyer et al, 2006;Schneider et al, 2009;Benamú et al, 2010;Santos et al, 2010;Al-Daikh et al, 2016). The results indicate an effect on the decrease of the population size with treatments of glyphosate .…”

“…1). It is important to clarify that currently it is not clear how the herbicide could directly affect these populations, since the herbicidal site of action does not exist in these arthropods, and it is exclusive to autotrophic organisms (Niemeyer et al, 2018;Pereira et al, 2018). However, both the metabolism of the herbicide in animals and the compounds accompanying the molecule's formulation must be taken into account, since there are often unknown inert substances that act as surfactants and can interact with arthropods (De Aguiar et al, 2016;Niemeyer et al, 2018).…”

“…All these practices can be performed to detect changes in the structure of communities and predict the effects of a habitat's alterations. In agriculture, it is possible to use edaphic entomofauna as a bioindicator (Pereira et al, 2018). In this context, springtails stand out since they have the capacity to colonize practically any agricultural environment, are easy to breed in the laboratory, have a short life cycle and, therefore, can respond quickly to environmental changes.…”