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Stability of contact insecticides. I—ultra‐violet photolysis of the pyrethrins
Author(s) -
Blackith R. E.
Publication year - 1952
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/jsfa.2740030506
Subject(s) - pyrethrum , photodissociation , decomposition , chemistry , ultra violet , photochemistry , sunlight , environmental chemistry , pesticide , materials science , organic chemistry , optics , optoelectronics , agronomy , biology , physics
In view of the discrepancy between the stability of pyrethrum‐in‐oil films in direct sunlight and in the dark, the persistence of such films under various conditions is reviewed, and the ultra‐violet photolysis is found to be by far the most active agent in decomposing such films. The action of ultra‐violet light on the insecticide is found to be independent of humidity or the presence of oxygen. Four processes are outlined by which the pyrethrins become inactivated. The prolonged residual effect of pyrethrum‐in‐oil films in the absence of light, established by earlier workers, is confirmed, and the decomposition is found to be independent of temperature, over the ordinary ambient range.