Efficacy of novaluron + pyriproxyfen (Tekko Pro) insect growth regulators against Amblyomma americanum (Acari: Ixodidae), Rhipicephalus (Boophilus) annulatus, Rhipicephalus (Boophilus) microplus, and Rhipicephalus sanguineus

Authors: Showler, Allan; DONAHUE, WILLIAM - SIERRA RESEARCH LABRATORIES; Harlien, Jessica; DONAHUE, MICHAEL - SIERRA RESEARCH LABRATORIES; VINSON, BRETT - SIERRA RESEARCH LABRATORIES; Thomas, Donald

Submitted to: Journal of Medical Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/23/2019
Publication Date: 5/18/2019
Citation: Showler, A., Donahue, W.A., Harlien, J.L., Donahue, M., Vinson, B. 2019. Efficacy of novaluron + pyriproxyfen (Tekko Pro) insect growth regulators against Amblyomma americanum (Acari: Ixodidae), Rhipicephalus (Boophilus) annulatus, Rhipicephalus (Boophilus) microplus, and Rhipicephalus sanguineus. Journal of Medical Entomology. 56(5):1338-1345. https://doi.org/10.1093/jme/tjz075.
DOI: https://doi.org/10.1093/jme/tjz075

Interpretive Summary: Hard ticks are global pests that transmit disease organisms to humans and animals. Growing resistance to conventional acaricides is increasing the need for alternative acaricides. Novaluron and pyriproxyfen are both insect growth regulators that, when used alone, show variable results against mites and ticks. We assessed the acaricidal effects of novaluron + pyriproxyfen (commercially marketed as Tekko Pro) against four tick species. Laboratory assays on the brown dog tick and the lone star tick reduced metabolic activity of larvae and nymphs. Tekko Pro dried on filter paper interfered with, but did not completely eliminate, larval brown dog tick molting but it was less effective against nymphs. Molting by lone star tick larvae, however, was reduced by >95% using a 4 µg/cm2 and 8 µg/cm2 eliminated molting. Nymphal lone star tick molting was reduced but not halted using 16 µg/cm2. On calves, Tekko Pro stopped larval lone star tick metabolic function one day post-treatment and no molting occurred. When larvae were released 30 d after treatment, metabolic activity and molting were reduced by 95% and 94%, respectively. Southern cattle fever tick larvae released one day after treatment on calves were 99% prevented from reaching adulthood. The treatment did not interfere with larval development when larvae were released 57 d after treatment.

Technical Abstract: Ixodid ticks are global pests that transmit medical and veterinary disease agents. Growing tick resistance to conventional acaricides is increasing the need for alternative acaricides. Novaluron and pyriproxyfen are both insect growth regulators that, when used alone, show variable results against acarines. We assessed the acaricidal effects of novaluron + pyriproxyfen (commercially marketed as Tekko Pro) against four tick species. Laboratory assays on the brown dog tick, Rhipicephalus sanguineus (Latreille), and the lone star tick, Amblyomma americanum (L.), reduced metabolic activity indicated by numbers of fecal deposits from larvae and nymphs. Novaluron + pyriproxyfen dried on filter paper interfered with, but did not completely eliminate, larval R. sanguineus molting while it was less effective against nymphs. Molting by A. americanum larvae, however, was reduced by >95% using a 4 µg/cm2 and 8 µg/cm2 eliminated molting. Nymphal A. americanum molting was reduced but not curtailed using 16 µg/cm2. On calves, novaluron + pyriproxyfen stopped larval A. americanum metabolic function one day post-treatment and no molting occurred. When larvae were released 30 d after treatment, metabolic activity and molting were reduced by 95% and 94%, respectively. Southern cattle fever tick, Rhipicephalus microplus (Canestrini), larvae released one day after treatment on calves were 99% prevented from reaching adulthood. The treatment did not interfere with larval development when larvae were released 57 d after treatment. The cattle fever tick, Rhipicephalus annulatus (Say), failed to reach adulthood when larvae were released on calves a day after treatment.