Grass species and climatic season impact on Rhipicephalus microplus temporal abundance in a tropical region.

BACKGROUND

The cattle tick Rhipicephalus microplus is a major constraint to livestock production in tropical regions, causing substantial economic losses and driving intensive acaricide use. Despite its importance, the role of pasture composition in shaping off-host tick populations remains poorly understood. This study evaluated whether forage grass species create distinct microenvironments that influence the seasonal abundance and persistence of R. microplus larvae in a tropical region.

RESULTS

Larval abundance was higher overall in the dry season than in the rainy season, with a significant interaction between grass and season. Grass cultivars differed markedly during the dry season. Two Megathyrsus maximus cultivars supported the highest larval densities and the longest recovery windows, whereas two Urochloa sp. cultivars showed the lowest larval densities. Differences in larval abundance were not significant during the rainy season across grasses (P = 0.13). Minimum temperature and minimum relative humidity were the most influential microclimatic predictors of larval abundance.

CONCLUSION

The interaction between forage species and seasonal climate influences R. microplus population dynamics, particularly under dry conditions. Although pasture composition alone is unlikely to determine infestation levels under grazing conditions, and larval abundance in pasture does not necessarily translate directly into infestation levels on cattle, certain grass cultivars may contribute to microenvironments less favorable for tick survival. These findings highlight the potential of forage species to influence off-host tick dynamics, acting as a complementary component of the integrated R. microplus management. © 2026 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.