Acute toxicities of permethrin, fenitrothion, carbaryl and carbofuran to mosquito larvae during single- or multiple-pulse exposures
Article first published online: 20 OCT 2009
Copyright © 1991 SETAC
Environmental Toxicology and Chemistry
Volume 10, Issue 9, pages 1229–1233, September 1991
How to Cite
Parsons, J. T. and Surgeoner, G. A. (1991), Acute toxicities of permethrin, fenitrothion, carbaryl and carbofuran to mosquito larvae during single- or multiple-pulse exposures. Environmental Toxicology and Chemistry, 10: 1229–1233. doi: 10.1002/etc.5620100914
- Issue published online: 20 OCT 2009
- Article first published online: 20 OCT 2009
- Manuscript Accepted: 24 JAN 1991
- Manuscript Received: 22 JUN 1990
- Ontario Ministry of Agriculture and Food
- Multiple-pulse exposure;
- Acute toxicity
The acute toxicity to third-instar Aedes aegypti (L.) of two 1-h exposures to each of five insecticides (technical permethrin, microencapsulated permethrin, fenitrothion, carbaryl, and carbofuran) was determined with static toxicity tests. The toxicity of two 1-h exposures to these test compounds, separated by a 6-h insecticide-free period, was compared to that of continuous 2-h exposures. Acute toxicity was expressed as LC50 values based on survival to the adult stage. The LC50 for two 1-h exposures to microencapsulated permethrin (180 μg/L) was significantly lower than that for a continuous 2-h exposure (250 μg/L). There was no significant difference between LC50 values for two 1-h and continuous 2-h exposures for each of technical permethrin (2.03–2.32 μg/L), fenitrothion (49.4–48.8 μg/L), carbaryl (3,040–3,470 μg/L, and carbofuran (1,590–2,130 μg/L).
Increasing time between two 1-h exposures to carbaryl from 6 to 24 h did not significantly affect acute toxicity (LC50 values were 3.0 mg/L and 3.8 mg/L, respectively). The LC50 for four 1-h exposures to carbaryl each separated by a 12-h period in clean water (LC50 = 1.7 mg/L) was not significantly different from that of a continuous 4-h exposure (LC50 = 1.4 mg/L). These results suggest that there was no recovery from the effect of insecticide poisoning during the insecticide-free period between exposures.