Inhibition of development in a field population of horn flies treated with diflubenzuron.

Development was inhibited in Haematobia irritans (L.) population when range cattle were treated with 0.5 or 1.0% sprays of diflubenzuron ( N -(4-chlorophenyl)- N ′-(2,6-difluorobenzoyl)urea). The 1% spray treatment resulted in failure of the eggs to hatch or in failure of the larvae to develop into pupae. Thus, adult emergence was virtually eliminated for 4 wk after treatment, sufficient time to break the life cycle. A bioassay showed that toxic levels of diflubenzuron or its metabolites remained in the manure for 15 days following a 1% spray treatment of the animals.