Field testing of the remotely operated sprayer for control of cattle fever ticks on nilgai

Authors: Goolsby, John; DEYOUNG, RANDY - Texas A&M University; HEWITT, DAVID - Texas A&M University; BAUMGARDT, JEREMY - Texas A&M University; ALFONSO ORTEGA-S, J - Texas A&M University; Shapiro Ilan, David; BONILLA, D - Animal And Plant Health Inspection Service (APHIS); HASEL, H - Animal And Plant Health Inspection Service (APHIS); Perez De Leon, Adalberto - Beto

Submitted to: Meeting Proceedings
Publication Type: Other
Publication Acceptance Date: 3/12/2020
Publication Date: N/A
Citation: N/A

Interpretive Summary: Nilgai antelope are implicated in the long-range movement of southern cattle fever ticks, Rhipicephalus microplus in the environment, especially in Cameron and Willacy Counties. Treatment methods for nilgai are needed to support the Cattle Fever Tick Eradication Program. Remotely activated sprayers developed for application of entomopathogenic nematodes at fence crossings were tested in the summer of 2019 at private ranches in Cameron Co., TX. Sprayers are activated by ultra-sonic sensors as nilgai transit through fence crossings. Nilgai are treated directly with entomopathogenic nematodes, Steinernema riobrave (microscopic parasitic roundworms) (Nemasys-R, BASF) to kill the ticks and passively as the nilgai contact adjacent wetted foliage and soil. Satellite collars and game cameras were used to determine movements of nilgai through established fence crossings and within the treated and untreated ranches. Pre and post treatment counts of R. microplus and other tick species on the satellite collared nilgai in the study areas showed positive results that the nematodes were controlling the tick populaton. These methods show promise for eradication of R. microplus on nilgai and the study will be refined and repeated in 2020.

Technical Abstract: Nilgai antelope Boselaphus tragocamelus (Pallas) are implicated in the long-range dispersal and cycling of southern cattle fever ticks, Rhipicephalus microplus Canestrini (Acari: Ixodidae) in the environment, especially in Cameron and Willacy Counties. Treatment methods for nilgai are needed to support the Cattle Fever Tick Eradication Program. Remotely activated sprayers developed for application of entomopathogenic nematodes at fence crossings were tested in the summer of 2019 at private ranches in Cameron Co., TX. Sprayers are activated by ultra-sonic sensors as nilgai transit through fence crossings. Nilgai are treated directly with Steinernema riobrave (Cabanillas, Poinar, and Raulston) entomopathogenic nematodes (Nemasys-R, BASF) and passively as they contact wetted foliage and soil. Satellite collars and game cameras were used to determine movements of nilgai through established fence crossings and within the treated and untreated ranches. Pre and post treatment counts of R. microplus and other tick species on the satellite collared nilgai in the study areas showed a significant treatment effect. These methods show promise for eradication of R. microplus on nilgai and the study will be refined and repeated in 2020.