rapid, efficient method for the bioassay of extracts, fractions and compounds for activity against tropical aphids

• Published in: International journal of pest management 2006-10, Vol.52 (4), p.333-342
• Main Authors: Quiros, D.I, Emmen, D.A, Dominguez, E, Heller, M.V, Coley, P.D, Kursar, T.A
• Format: Article
• Language: English
• Subjects: Aphididae; Aphis craccivora; Aphis gossypii; artificial diet; bioassays; Biological and medical sciences; botanical insecticides; clonal; colonies; dietary exposure; Fundamental and applied biological sciences. Psychology; insect control; insecticidal properties; mortality; Phytopathology. Animal pests. Plant and forest protection; plant extracts; Plant metabolites; plant proteins; protein extracts; Protozoa. Invertebrates; rapid methods; secondary metabolites; Sternorrhyncha; toxicity testing; tropical forest
• ISSN: 0967-0874; 1366-5863
• DOI: 10.1080/09670870600847525

Although aphids remain serious pests, bioassay-guided purification of anti-aphid compounds depends upon assays that are laborious and often have incomplete descriptions of methods. We provide the protocol for a rapid, efficient assay using a 96-well microtiter plate format for testing extracts for activity against the cotton aphid, Aphis gossypii Glover (Sternorrhyncha: Aphididae), and the black bean aphid, Aphis craccivora Koch. Assays of extracts composed of low molecular weight metabolites from 28 species of plants from 15 families from Panamanian forest showed variation in toxicity to A. craccivora. Three metabolite extracts and one protein extract were active, with more than 70% mortality in 72 h, averaged over three independent experiments. For three species of plants with protein extracts having intermediate activity, the metabolite extracts were inactive; hence, the activity probably was due to the toxic proteins, rather than contaminating toxic metabolites.