End-point Dilution and Plaque Assay Methods for Titration of Cricket Paralysis Virus in Cultured Drosophila Cells

Cricket paralysis virus, an insect picorna-like virus, caused a distinct c.p.e. in cultured Drosophila melanogaster cells, allowing the development of titration methods based on end-point dilution or plaque assay methods. The end-point dilution (TCD₅₀) method is more sensitive and economical than plaque assays and is easily scored. The data indicate a minimum infectivity/particle ratio of about 1/2000.