Abstract

The effect of exposing entomopathogenic bacteria isolated from tick (Rhipicephalus decoloratus) to variable intensities of electromagnetic field for different periods of time was examined on their pathogenicity on tick. Some bacterial isolates from the macerate of tick cadavers were used in the infection of healthy engorged ticks. Two of the bacteria tested namely Proteus mirabilis and Bacillus cereus were able to induce morbid conditions in the ticks both of which were re-isolated from the resulting tick cadavers. Re-infection of different concentrations of both entomopathogenic bacteria of ticks were carried out on the tested ticks to determine the minimum lethal concentration required for pathogenicity. The result reveals that P. mirabilis and B. cereus were able to cause disease at concentrations of 10⁶ and 10⁷ cfu/ml, respectively. These bacteria were then exposed to electromagnetic field with different intensities for different periods of time after which they were re-infected into healthy insects. Conclusively, the study reveals some signs of stimulation in the entomopathogenic potency of B. cereus after exposure to electromagnetic field (EMF) when compared to the control treatments while a significant reduction in the entomopathogenic potency of P. mirabilis was recorded.

Key words: Entomopathogens, electromagnetic field, Proteus mirabilis, Bacilluscereus.