title: Effect of two herbicides on Xenylla welchi (Hexapoda:Collembola) under laboratory conditions.
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).
authors.affiliation: Department of Zoology, Raja N.L. Khan Women's College, Midnapore, Paschim Medinipore, 721102 West Bengal, India.
authors.forename: A
authors.initials: A
authors.lastname: Haque
authors.forename: R
authors.initials: R
authors.lastname: Das Gupta
authors.forename: P P
authors.initials: PP
authors.lastname: Chakravorty
mesh_terms: D000083:Acetanilides / Q000633:toxicity*; D000814:Aniline Compounds / Q000633:toxicity*; D000818:Animals; D001181:Arthropods / Q000187:drug effects*; D006540:Herbicides / Q000633:toxicity*; D007928:Lethal Dose 50; D018978:Molting / Q000187:drug effects
chemical_list: D000083:Acetanilides; D000814:Aniline Compounds; D006540:Herbicides; C118050:pretilachlor; C030856:pendimethalin