Survival, developmental and morphogenic deficiencies of parasarcophaga argyrostoma [diptera: sarcophagidae] induced by the biosynthesis inhibitor chlorfluazuron [IKI-7899]

ABSTRACT

To evaluate the activity of benzoylphenyl urea chitin biosynthesis inhibitor chlorfluazuron [IKI-7899] against Parasarcophaga argyrostoma, 7 doses were topically applied [once] onto early third [last] instar larvae, puparia, or newly pupa 150, 100, 50, 10, 1, 0.5 and 0.25 mug/insect. After topical treatment of last instar larvae, the highest morality was caused by both highest dose and the lowest mortality was caused by the lowest dose. The lethal activity of IKI-7899 pronouncedly decreased as the treatment was lately carried out [at the puparial time]. IKI-7899 failed to cause cumulative mortality because no pupal or adult mortalities were observed, irrespective of the time of treatment. Treated larvae suffered the action of IKI-7899 because they had decreased weight gain. Except the lowest dose, the weight gain of larvae inversely correlated with the dose levels. IKI-7899 prolonged not only the larval duration, but also the pupal duration after topical treatment of last instar larvae with doses 50 - 0.25 mug/larva. With no exception, all doses topically applied onto puparia or newly formed pupae enhanced pupae to live longer. Topical application onto last instar larvae resulted in different degrees of reduction of pupation rate, but IKI-7899 could not affect the pupal morphogenesis after larval treatment except by its highest dose, which led to 8.33% pupal deformities and 7.69% larval-pupal intermediates. The dose 100 mug/larva topically applied onto last instar larvae obtained 7.69% permanent larvae, which suffered from the action of compound along 16 days and eventually perished without any external feature of puparium formation. A metamorphic effect of IKI-7899 pronouncedly appeared in the adult stage. Three higher doses completely arrested the adult flies