Location: Cattle Fever Tick Research Unit
Project Number: 3094-32000-042-020-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Jul 1, 2018
End Date: Apr 30, 2022
1. Confirm the tick-growth regulating activity of a 3% diflubenzuron feed through formulation when fed to cattle according to label instructions. 2. Test the consumption/palatability of white-tailed deer feed preparations that can serve as a delivery system for 3% diflubenzuron to treat ticks on deer and, subsequently, test the effect on tick growth of the afore determined "best" deer feed candidate containing 3% diflubenzuron using a bioassay of blood from treated deer and analysis of diflubenzuron levels in blood/serum. 3. Test a spray formulation containing 3% diflubenzuron for tick activity using cattle.
Tick-growth regulating activity of feed through formulations that contains 3% diflubenzuron will be evaluated in cattle and white-tailed deer. A 3% spray formulation will be evaluated in cattle. Initially, stanchioned cattle at the Knipling Bushland U.S. Livestock Insects Research Laboratory will be fed a feed through formulation of 3% diflubenzuron to determine effects on tick development. Cattle will be stanchioned and given a daily grain ration that contains the appropriate added dose of 3% diflubenzuron by body weight for 14 days before tick infestation. Tick development and mortality will be evaluated daily for cattle infested with Amblyomma americanum and Dermacentor albipictus (a single host tick with a life cycle similar to Rhipicephalus microplus and R. annulatus). Fecundity data from engorged females will also collected. Additionally, blood samples will be taken on a routine basis (day 0, 1, 3, 4, 7, 14, 21, 28, etc.) for analysis of diflubenzuron levels. Blood samples will also be sent to CFTRL where capillary tick feeding bioassays will be performed to evaluate the impact on development of R. microplus and R. annulatus. If significant developmental impacts are observed for R. microplus and R. annulatus, a Phase Two quasi-field study may be performed at CFTRL to evaluate the feed through formulation for R. microplus infested cattle in a pasture. A captive herd of white-tailed deer at TAMUK will be used to test different feed preparations. Acceptance, consumption, and palatability of the formulation for use in white-tailed deer will be evaluated. The feed preparation preferred by deer will be formulated with 3% diflubenzuron. Deer will then be provided the feed preparation containing 3% diflubenzuron. A set of blood samples will be taken from the treated deer on a routine basis (day 0, 3, 4, 7, 14, 21, 28, etc.) for analysis for diflubenzuron levels. Another set of blood samples will be sent to CFTRL where capillary feeding bioassays will be performed to evaluate growth effects against R. microplus and R. annulatus. A separate stall test will be performed to evaluate a 3% spray formulation of diflubenzuron for growth activity against R. microplus. Cattle infested with R. microplus will be sprayed with a 3% formulation of diflubenzuron and will be monitored for impact on R. microplus development. Tick counts will be taken weekly and impact on tick growth will be noted.