Efficacy of Novaluron + Pyriproxyfen (Tekko Pro) Insect Growth Regulators Against Amblyomma americanum (Acari: Ixodidae), Rhipicephalus (Boophilus) annulatus, Rhipicephalus (Boophilus) microplus, and Rhipicephalus sanguineus.

Ixodids are globally distributed pests that transmit many disease agents. Increasing resistance to conventional acaricides raises the need for alternative tactics. Novaluron and pyriproxyfen are insect growth regulators (IGRs) that have variable potencies against acarines. We conducted in vitro and in vivo experiments to assess novaluron + pyriproxyfen (marketed as Tekko Pro) against four ixodid species. Laboratory assays on the brown dog tick, Rhipicephalus sanguineus (Latreille) (Ixodida: Ixodidae), and the lone star tick, Amblyomma americanum (L.) (Ixodida: Ixodidae), reduced metabolic activity in larvae and nymphs. Concentrations of novaluron + pyriproxyfen dried on filter paper impeded molting of larval R. sanguineus (less effective against nymphs). Molting A. americanum larvae were reduced by >95% using 4 and 8 µg/cm2 eliminated molting; nymphal molting was reduced but not halted even at 16 µg/cm2. On calves, novaluron + pyriproxyfen stopped larval A. americanum metabolic function 1 d post-treatment and larvae did not molt. When larvae were released 30 d after treatment, metabolic activity was reduced by 95% and molting was reduced by 94%. Southern cattle fever tick, Rhipicephalus (Boophilus) microplus (Canestrini) (Ixodida: Ixodidae), larvae released 1 d after treatment on calves were 99% prevented from reaching adulthood. The treatment did not interfere with larval development when larvae were released 52 d after treatment. The cattle fever tick, Rhipicephalus (Boophilus) annulatus (Say) (Ixodida: Ixodidae), failed to reach adulthood when larvae were released on calves a day after treatment (residual activity was not assessed for R. annulatus). These IGRs, and possibly others, offer an alternative to conventional acaricides for ixodid control on cattle.

Lethal Effects of the Insect Growth Regulator Cyromazine Against Three Species of Filth Flies, Musca domestica, Stomoxys calcitrans, and Fannia canicularis (Diptera: Muscidae) in Cattle, Swine, and Chicken Manure.

The presence of various species of filth flies is a widespread problem where livestock, including poultry, are maintained and where manure accumulates. The house fly, Musca domestica L.; the stable fly, Stomoxys calcitrans (L.); and the little house fly, Fannia canicularis (L.) (each Diptera: Muscidae), the target pests in our study, can mechanically spread diseases, and S. calcitrans can bite cattle, causing losses in meat and milk production. Chemical control is widely used to suppress filth flies, but resistance to conventional insecticides has become problematic. Hence, an alternative approach, insect growth regulators (IGRs), has been adopted by many livestock producers. We assessed the ability of the IGR cyromazine in granular and granular-based aqueous formulations to suppress the three muscid species from developing in poultry, cattle, and swine manure collected from commercial livestock production facilities. Each of the two formulations provided either strong or complete control of the pests for the 4-wk duration of the study, excluding the granular formulation that provides control of only F. canicularis developing in poultry manure for 2 wk. The two cyromazine-based IGR formulations appear to be effective tools that, if rotated appropriately with other insecticides, can be incorporated into integrated pest management strategies for filth fly suppression.