Selective Toxicity of Carbophenothion and Trichlorfon to the Honey Bee and the Alfalfa Leafcutting Bee

Authors

Zahoor Ahmad, Washington State University
Carl Johansen, Washington State University

Document Type

Article

Journal/Book Title/Conference

Enviornmental Entomology

Volume

2

Issue

1

Publication Date

2-1-1973

First Page

27

Last Page

30

Abstract

Selective toxicity of carbophenothion and trichlorfon to the honey bee, Apis mellifera L., and the alfalfa leafcutting bee, Megachile rotundata F., was established in dosage-mortality studies using the topical drop method. LD5 0 values of trichlorfon for the honey bee, the male leafcutting bee, and the female leafcutting bee were 28.5, 250.0, and 515.0 μ,gi g, respectively. LD5 0 values for carbophenothion were 12.6, 4.3, and 6.2 μ,gi g. Trichlorfon was 18- 34 times more toxic to the honey bee than to the female leafcutter at LD5 0 and LD95 Carbophenothion was 2-3 times more toxic to the leafcutting bee at both dosage levels. The differential toxicity of trichlorfon may be related to pH of the body fluid, which was 6.0 for the honey bee and 6.8 for the leafcutting bee. Trichlorfon is known to be highly unstable at neutral or higher pH levels. Trichlorfon at the topical LD50 levels was a stronger acetylcholinesterase inhibitor than carbophenothion to both test insects.

Recommended Citation

Ahmad, Zahoor and Johansen, Carl, "Selective Toxicity of Carbophenothion and Trichlorfon to the Honey Bee and the Alfalfa Leafcutting Bee" (1973). A. Paper 41.
https://digitalcommons.usu.edu/bee_lab_a/41