Acaricidal activity of the hyacinthacine analogues derived from pyrrolizidine alkaloids on Rhipicephalus (Boophilus) microplus.

This study reports the effect of six hyacinthacine analogues derived from pyrrolizidine alkaloids on egg hatchability and mortality rates of newly hatched larvae of the cattle tick Rhipicephalus (Boophilus) microplus. All the compounds were toxic to the larvae of the ticks and inhibited the eggs hatchability in the higher concentration tested (5 microg/ml). Even in the lowest concentration (0.