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ARS Home » Plains Area » Kerrville, Texas » Knipling-Bushland U.S. Livestock Insects Research Laboratory » Cattle Fever Tick Research Unit » Research » Publications at this Location » Publication #407532
Research Project: Integrated Pest Management of Cattle Fever Ticks

Location: Cattle Fever Tick Research Unit

Title: Degree-days and off host longevity of cattle fever ticks, Boophilus spp. (Acari: Ixodidae) in south Texas pastures

Author
item AROCHO, CHARLUZ M. - Texas A&M University
item LEAL, BRENDA - Texas A&M University
item Thomas, Donald

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/12/2023
Publication Date: 12/29/2023
Citation: Arocho, C., Leal, B., Thomas, D.B. 2023. Degree-days and off host longevity of cattle fever ticks, Boophilus spp. (Acari: Ixodidae) in south Texas pastures. Journal of Economic Entomology. https://doi.org/10.1093/jee/toad237.
DOI: https://doi.org/10.1093/jee/toad237

Interpretive Summary: Cattle fever ticks are found throughout Latin America and transmit cattle fever, a disease that kills livestock. The United States has an eradication program, applied mainly in Texas, to exterminate the ticks when they are found on border region ranches. A ranch is placed under quarantine when it is found to be infested. Under present law, the ranch is quarantined for either 6 months or 9 months, depending on the season. Summer infestations are quarantined for 6 months, winter infestations for 9 months. Our research shows that ticks will not survive in a pasture for more than 4-5 months, even in winter, and thus a 6 month quarantine is adequate.

Technical Abstract: Cattle fever ticks are native to Eurasia and have invaded the New World as vectors of bovine Babesiosis. The secondary host range includes horses and deer. An eradication program by the USDA eliminated these ticks from the U.S. except for a quarantine zone in Texas along the Rio Grande. Premises infested with Boophilus ticks are subject to regulatory oversight that include acaricide treatment and quarantine. The quarantine duration varies between summer and winter and is based on the available information on the persistence of the off-host stages in pastures far from south Texas. The objective of this project was to assess the specific effect on B. annulatus and B. microplus of thermal stress measured in degree-days on longevity of off-host stages in south Texas pastures. Tick gardens were placed in a south Texas pasture and larval survival measured year round for both species over a 3 year period. In our results the longest off-host persistence for B. annulatus was 142 days in canopied habitat in the winter and 130 days in the summer. On the other hand, B. microplus off-host persistence was 113 days under canopy and 103 days in exposed habitat, both in winter. The results indicate that temperature was a key variable that prolongs the survival of B. annulatus but not B. microplus. It is likely that B. microplus, a species adapted to tropical latitudes, is not able to survive in areas with harsh winters. Vegetative cover and humidity are key factors for its survival. In areas such as south Texas at the northern most extent of its range where mild winters prevail, we found a maximum persistence of less than four months (113 days), very close to the previous published record of 116 days. A reduction in the pasture quarantine period from 9 months to 6 months would be justified for this species.