If you are experiencing problems downloading PDF or HTML fulltext, our helpdesk recommend clearing your browser cache and trying again. If you need help in clearing your cache, please click here . Still need help? Email help@ingentaconnect.com

An Insecticidal Method for the Estimation of Kerosene Extracts of Pyrethrum

$28.00 plus tax (Refund Policy)

Buy Article:


A method for evaluating pyrethrum extracts is described. It was found that different strengths of pyrethrum extracts vary directly in the speed with which they paralyze flies. A series of similarly performed tests indicated that the reproducibility of the results is great, especially the values for speed of paralytic action. The per- centage mortalities produced by such a series extended over a wider range but statistical analysis indicated that this variation was well within the limits of errors due to random sampling. Typical paralytic curves are shown and the value of the 50% paralytic point (the time when 50% of the insects are paralyzed) for making comparisons is pointed out. For a series of various concentrations of pyrethrum extracts the differences in mortality were not very great. This criterion of toxicity can only be used for diagnosing differences between extracts which differ widely in concentration. Differences in speed of paralytic action between a 3/4 pound and a 1 pound extract of a fairly powerful grade of pyrethrum powder (0.26% Pyrethrin I) were easily distinguishable and were found to be clearly significant as indicated by statistical analysis. The differences in percentage mortality, analyzed similarly, were not significant.

Document Type: Research Article

Publication date: February 1, 1931

More about this publication?
  • Journal of Economic Entomology is published bimonthly in February, April, June, August, October, and December. The journal publishes articles on the economic significance of insects and is divided into the following sections: apiculture & social insects; arthropods in relation to plant disease; forum; insecticide resistance and resistance management; ecotoxicology; biological and microbial control; ecology and behavior; sampling and biostatistics; household and structural insects; medical entomology; molecular entomology; veterinary entomology; forest entomology; horticultural entomology; field and forage crops, and small grains; stored-product; commodity treatment and quarantine entomology; and plant resistance. In addition to research papers, Journal of Economic Entomology publishes Letters to the Editor, interpretive articles in a Forum section, Short Communications, Rapid Communications, and Book Reviews.
  • Editorial Board
  • Submit a Paper
  • Subscribe to this Title
  • Information for Advertisers
  • Visit this journal's homepage
  • ingentaconnect is not responsible for the content or availability of external websites
Related content



Share Content

Access Key

Free Content
Free content
New Content
New content
Open Access Content
Open access content
Subscribed Content
Subscribed content
Free Trial Content
Free trial content
Cookie Policy
Cookie Policy
ingentaconnect website makes use of cookies so as to keep track of data that you have filled in. I am Happy with this Find out more