A model of the survival of larvae of the cattle tick, Boophilus microplus, on pasture

Abstract

Larvae of Boophilus microplus were released onto pasture in south-eastern and central Queensland and their survival was measured using destructive sampling. In summer 50% of the larvae survived for 2 weeks and 10% survived for 4 weeks. Comparable values for winter were 3-4 and 6-11 weeks respectively. A chart was prepared to relate larval survival to maximum temperatures in summer, when pasture spelling for tick control is most likely to be successful. A computer simulation model was developed to describe the survival of the larvae in relation to meteorological conditions. The parameter values were fitted using the data from south-eastern Queensland and tested against observations made in central Queensland. Maximum temperature and saturation deficit at 1500 hours proved to be the best predictors of survival, but it was not possible to distinguish between their effects.