Ishaaya, I., Division of Entomology, The Volcani Institute of Agricultural Research, Bet Dagan, Israel
Swirski, E., Division of Entomology, The Volcani Institute of Agricultural Research, Bet Dagan, Israel

A rapid laboratory test for determining death in the Florida red scale (Chrysomphalus aonidum (L.)) and the California red scale (Aonidiella aurantii mask.) based on enzymatic activity is described. This test is based on the ability of the live scale enzymes to react with iodine, yielding iodine products which in turn are unable to give the blue color reaction with starch. The reaction seems to be due to the decrease in the oxidation number of the iodine from I0 - I-1 by the scale reductive enzymes. The longevity of the females after detachment from the host or after treatment with insecticides commonly used in the field, was determined by this test. © 1970 North-Holland Publishing Company.