Premium
Aqueous formulations of pyrethrum for controlling phytophagous Arthropoda—an evaluation using bioassay techniques
Author(s) -
YULE W. N.
Publication year - 1964
Publication title -
annals of applied biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.677
H-Index - 80
eISSN - 1744-7348
pISSN - 0003-4746
DOI - 10.1111/j.1744-7348.1964.tb03776.x
Subject(s) - pyrethrum , piperonyl butoxide , biology , bioassay , acyrthosiphon pisum , aphid , carbamate , toxicology , diflubenzuron , botany , aphididae , pesticide , pest analysis , agronomy , larva , biochemistry , homoptera , ecology
SUMMARY Bioassay techniques were used to compare the toxicities of formulations of pyrethrum containing different amounts of surface‐active agents (mainly non‐ionic condensates of ethylene oxide) and synergists (Bucarpolate, piperonyl butoxide, S 421 and Sulfoxide). Phytophagous species of Arthropoda used in the tests were: Acyrtho‐siphon pisum Harris (Aphididae); Phaedon cochleariae F. (Chrysomelidae); Pieris brassicae L. (Pieridae); and Tetranychus telarius L. (Acarina, Tetranychidae). The insects were dosed by spray tower, and the mite by dipping infested leaves. The LC 50 pyrethrins with unsynergized formulations were: aphid (adult), 150 p.p.m.; beetle (adult), 50,910 p.p.m.; caterpillar (third instar), 325 p.p.m.; mite (adult) 1168 p.p.m. Formulations whose wetting powers were increased by adding surface‐active agents were more toxic to the aphid and caterpillar (LC 50 of 20 and 50 p.p.m., respectively). Addition of piperonyl butoxide or Sulfoxide to formulations, at up to 8 times the concentration of pyrethrins, increased their potencies for the aphid, beetle and mite by factors of 7–10 times, but were ineffective with the caterpillar. Bucarpolate and S 421 were poor synergists. A detailed study was made, using Acyrthosiphon pisum , of the synergizing effect of surface‐active agents on formulations of pyrethrum. Hypotheses for their modes of action suggest that toxicity is influenced by the fineness of dispersion of pyrethrum emulsions, and by the improved coverage and penetration of spray on insects, which results from increased wetting power. The results of bioassay studies are interpreted to indicate that a formulation of pyrethrum synergized with both surface‐active agent and piperonyl butoxide would be a very effective aphicide, with some ovicidal and larvicidal properties, when applied to infested plants as a high‐volume spray.