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
Subject(s)
Insecta/drug effects , DiflubenzuronABSTRACT
The new non-steroidal ecdysone mimic, RH-5849 [1, 2-benzoyl-1-tert-butylbenzohydrazine] was investigated, its biological actions were evaluated in the laboratory against a susceptible strain of Musca d. vicina. The larvae of 1-day old and of 4-day-old were fed on diets treated with different concentrations of the compound. RH-5849 shortened the larval and pupal durations and induced the initiation of premature lethal moult. The pupation rate was highly affected, where it was reduced to 46.7% at a concentration rate of 250 ppm. Also, the adult emergence was drastically blocked by the action of RH-5849 where its percentage was decreased to 42.9 at 250 ppm. In regard to the fecundity and egg viability, RH-5849 induced a cessation of oviposition in females produced from 1-day-old and from 4-day-old larvae fed on diets treated with 160 and 200 ppm, respectively. In addition, RH-5849 halted the larval and pupal growth, where the untreated pupae were generally heavier than those produced from treated larvae