[The action of a synthetic juvenile hormone analog on the flea Xenopsylla skrjabini].

In search of effective means of harmful fauna control, which could be practically safe for man and domestic animals, the authors tested efoxen-II, a juvenile insect hormone analogue (JHA) synthesized at the Institute of Chemistry, the Estonian Acad. of Sci. (Tallinn). Experiments were performed with Xenopsylla skrjabini Ioff., 1903 fleas under laboratory conditions. The doses of the drug tested were the following: 0.25.10(-2); 0.25 X 10(-3); 0.25.10(-4); 0.25.10(-5) ml/g per 1 g the substrate consisting of sand and dry bovine blood (for larvae feeding). Juvenile fleas' contact with the drug altered the normal metamorphosis process, thus killing the majority of fleas. The drug given in a dose of 0.25.10(-2) ml/g killed 100% of larvae by the 8th day of the experiment. The drug added to the substrate at 0.25.10(-3) ml/g prolonged metamorphosis stages, some larvae were killed during the moult, others (0.3%) formed pupae and died inside them. Larvae contact with the drug at 0.25.10(-4) and 0.25.10(-5) ml/g resulted in partial death. The insects survived (36.6 and 46.6%, respectively) completed metamorphosis by imago hatching. Thus, the drug tested by the authors proved to be considerably effective and may be recommended for in situ testing.