0023-6152

AA00697606

23887

Unrefereed

0023-6152

AA00697606

The present study elucidated the difference in seasonal fluctuation of the cattle tick (Haemaphysalis Longicomis) populations between Sasaguri pasture and a pasture at Kuja highland with different climates, and the effete of ambient temperatures on the tick activity was discussed. In Sasaguri pasture, the peak number of the ticks collected by dragging occurred according to the instar in order of nymphs (April)+adults and larvae (July)+nymphs (September). At Kujti highland, on the other hand, the peak number appeared in sequence of nymphs (June)-+adults (July)+larvae and nymphs (September) : in this case more ticks were captured under shade trees than on grassland. Such disparities seemed due to the difference of temperature between the two districts. The ticks in the field were able to overwinter underground in the unfed larval and nymphal states : the majority of the ticks were obtained at the depth of 5-15 cm from the ground surface under the shade trees, Overwintering experiments revealed that the ticks became less active or inactive when the ambient temperature at noon went down to 11-WC, and that the survival ratio was 38.5% for larvae, 28.0% for nymphs and 68.0% for adults (females, 64.0% ; males, 72.0%).