Entomopathogenic fungi (Aspergillus oryzae) as biological control agent of cattle ticks in Tanzania

Abstract

Ticks are the most important ectoparasites that are responsible for severe economic losses in livestock industry. The use of chemical acaricides is the most common method used to control ticks in livestock. This study was conducted to determine the efficacy of Aspergillus oryzae as an alternative biological agent in controlling ticks to enhance livestock productivity. The efficacy of A. oryzae at different concentrations was evaluated against larvae and adults of the hard tick genera Rhipicephalus, Boophilus, and Amblyomma using an immersion test under laboratory conditions. Field trials were conducted in two purposively selected cattle herds in Monduli district, northern Tanzania. A. oryzae at a concentration of 1 × 10 6 conidial/ml was sprayed on all cattle tick-infested areas. The results demonstrated a concentration-related increase in mortality for both larvae and adult female engorged ticks. The mean mortality of larvae and female engorged ticks was statistically significant at p ˂ 0.05 and p ˂ 0.001, respectively. Egg production was found to decrease with increased A. oryzae concentration. Additionally, there was a statistically significant difference in egg production index and oviposition reduction (p = 0.009) while there was no significant difference in egg hatching and product effectiveness at p = 0.089 and p = 0.004, respectively between the tested ticks' genera. Under field conditions, the bio-acaricide demonstrated a statistically significant tick reduction in all the treated cattle. This study concludes that A. oryzae has good acaricidal activity against ticks and hence, is one of the potential tick control methods for sustainable tick control schemes.