Assessing the impact of glyphosate on Scarites anthracinus (Coleoptera: Carabidae) and Octolasion cyaneum (Annelida, Oligochaeta, Lumbricidae)

SALVIO C., LÓPEZ A.N. , MANETTI P.L. , CLEMENTE N.L. , MENONE M.L

Montevideo

Workshop; 3rd Latin American Pesticide Residue Workshop, Food and Environment; 2011

Pharmacognosy and Natural Products , Faculty of Chemistry- Uruguay

Glyphosate is a nonselective systemic herbicide most commonly used in Argentina and therefore may be exert adverse effects on non-target organisms in the soil as carabid beetles and earthworms. Thus, the aim of this study was evaluated the effect of glyphosate on predator carabid Scarites anthracinus (Carabidae) and earthworms Octolasion cyaneum (Lumbricidae). The bioassay on S. anthracinus consisted of placing one adult in a plastic container of 20cm x 20cm with 2 cm of moist soil (29% clay, 21% fine silt, 16% coarse silt, 35 % sand and 5.98 % organic matter, ph=6) and 24 g of plant residues (wheat). The treatments were: 0, 120, 240, 480, 960 and 1440 g ha-1 of glyphosate active ingredient (a.i.) sprayed on the surface. Individuals were seen alive, dead or with symptoms of intoxication at 24, 48, 72, 96 and 120 hours after application (hDA). The design was completely randomized with 12 replicates and the containers were placed in a chamber at 20+2 C and 14L: 10O. The earthworm bioassay was a plastic container of 1000 cc which was placed 750 g of soil moist (same properties as the above soil) mixed with doses of the pesticide and 10 adult individuals with a weight of 500-700 mg. The treatments were the same as S anthracinus biossay. The observations were made at 7, 14, 21 and 28 days after application (DAA) and biomass in wet weight, individual dead and/or alive, cocoon and juveniles production were determined. The assay was extended to 60 DAA to observe cocoon and juveniles production. The design was completely randomized with 4 replicates and the containers were placed in a chamber at 20 +2¨¬C and 14L:10O. Data were analyzed using analysis of variance and when significant treatment differences were detected, means were separated by least significant difference (¥á=0.05). In both bioassays S. anthracinus and O. cyaneum 100% survival of individuals was observed. In addition, there were no symptoms of intoxication on S. anthracinus by the application of the herbicide and therefore carabid behavior was normal during the whole experience. On the other hand, in the earthworm bioassay there was no difference in biomass in wet weight between treatments at 7, 14, 21 and 28 DAA (p<0.05). No differences between treatments in the cocoon and juveniles production at 60 DAA (p<0.05) were observed. Thus, we conclude that the application of the herbicide glyphosate at evaluated doses not caused adverse effects on S. anthracinus and O. cyaneum.