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Bulletin of environmental contamination and toxicology

Effect of two herbicides on Xenylla welchi (Hexapoda:Collembola) under laboratory conditions.


PMID 21523507

Abstract

Xenylla welchi was used to evaluate toxicity of two herbicide formulations, pretilachlor (50 EC) and pendimethalin (30 EC) under laboratory conditions. Twenty four hours LC₅₀ value of pretilachlor and pendimethalin formulations on Xenylla welchi were 72.7 and 190.0 g a.i/ha respectively which were less than their corresponding recommended agricultural doses. Again pretilachlor attained fastest LT₅₀ (110 min) followed by pendimethalin (140 min). Significant reductions in hatching success were noted with the application of both the herbicide formulations at all doses excepting ¹/₈ and ¹/₁₀th of LC₅₀ (9.1, 7.3 and 23.8, 19.0 g a.i/ha for pretilachlor and pendimethalin, respectively). Hatching success of the test specimens recorded 44.1 and 63.3% reduction from control for the highest applied dose (½ of LC₅₀) of pretilachlor and pendimethalin, respectively. Juveniles of Xenylla welchi exposed to ¹/₆, ¹/₈ and ¹/₁₀th LC₅₀ for pretilachlor (12.1, 9.1, 7.3 g a.i/ha) and ¹/₈ and ¹/₁₀th LC₅₀ for pendimethalin (23.8, 19.0 g ai/ha) survived and exhibited increased moulting frequency (7 moultings in 28 days in both the herbicide treatments) in comparison to control (8 moulting in 42 days). Test specimens required 26.0 ± 1.2 and 28.1 ± 2.1 days to attain sexual maturity exposed to pretilachlor and pendamethalin respectively which was significantly less than control (42 ± 2.6 days).