Effects of the bipyridylium herbicides diquat dibromide and paraquat dichloride on growth and development of Neobellieria bullata (Diptera: Sarcophagidae) larvae.

Diet containing diquat dibromide (1,000 or 2,000 ppm) caused an extension of the first-instar stadium of Neobellieria bullata (Parker); the first molt was primarily disturbed. Pupariation was delayed when early-wandering larvae had been injected with diquat dibromide (18 micrograms/larva; approximately to 150 ppm). This effect of diquat dibromide was eliminated by simultaneous injection of 20-OH ecdysone (0.02 micrograms/larva). After larvae in the red spiracle stage were injected with diquat dibromide (5 micrograms/larva; approximately 42 ppm), evagination of the pupal head was inhibited. Paraquat dichloride was less active than diquat dibromide and appears to be a safer herbicide for use around decomposer fly species.