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ENGLISH‐GROWN PYRETHRUM AS AN INSECTICIDE. I
Author(s) -
FRYER J. C. F.,
TATTERSFIELD F.,
GIMINGHAM C. T.
Publication year - 1928
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.1744-7348.1928.tb07064.x
Subject(s) - pyrethrum , biology , aphis , pesticide , toxicology , seedling , toxicity , botany , horticulture , agronomy , chemistry , aphid , organic chemistry
Summary.1 The toxicity to Aphis rumicis L. and to certain caterpillars of spray fluids prepared from samples of pyrethrum ( Chrysanthemum cinerariaefolium ) grown in England from Swiss and Japanese seed have been quantitatively determined. 2 Pyrethrum flowers, grown in six different localities, showed only slight differences, and, for practical purposes, all the samples had approximately the same toxicity. They did not differ in this respect significantly from a sample grown on the continent. 3 The toxicities of extracts of equal weights of pyrethrum flowers tested at different stages of development differed very little. 4 Artificial drying of the flowers had no significant effect on the toxic properties. 5 The flowers were about ten times as toxic as the stalks, weight for weight. 6 Prolonged exposure of pyrethrum to wet conditions led to some loss of toxicity, but. contrary to the usual opinion, if stored in a reasonable manner, it remained for long periods without deterioration. 7 Caterpillars of different species showed marked differences in susceptibility to the action of pyrethrum. 8 The biological method employed has proved suitable for evaluating samples of pyrethtum.