Polar Perry, de Muro Marilena Aquino, Kairo Moses T K, Moore Dave, Pegram Rupert, John Sally-Ann, Roach-Benn Cheryl
CAB International, Caribbean and Latin America Regional Centre, Curepe, Trinidad and Tobago.
Vet Parasitol. 2005 Nov 25;134(1-2):159-67. doi: 10.1016/j.vetpar.2005.07.010. Epub 2005 Aug 11.
Experiments were conducted to determine if Metarhizium anisopliae isolates which are capable of growth at cattle surface temperatures could produce pathogenicity to Boophilus microplus in laboratory and field studies. The diurnal temperature fluctuation on the surface of cattle was monitored. The temperature tolerance of M. anisopliae isolates (ARSEF3297 and IMI386697) was determined and their pathogenicity to B. microplus compared at a standard bioassay temperature (28 degrees C) and at a temperature similar to the cattle surface (31-35 degrees C). The effect of the two isolates on the B. microplus population on cattle under field conditions was determined. The temperature of the fore udder, rear udder, ribs and neck regions of the mixed Holstein cattle fluctuated between 30 and 35 degrees C, in a similar pattern to the prevailing environmental temperature. However, wider fluctuations were obtained on the ears (28-35 degrees C) and spine (30-41 degrees C). The colony radius of both isolates declined as temperature increased, however, the growth of IMI386697 was five times greater than ARSEF3297 at 34 degrees C. At 28 degrees C, the pathogenicity of both isolates to B. microplus was similar, however, at 31-35 degrees C, IMI386697 was more pathogenic than ARSEF3297. Both isolates reduced the B. microplus population on cattle in comparison to the control formulation. However, IMI386697 (8.5+/-0.64 ticks/animal) produced a greater reduction in tick numbers than ARSEF3297 (19.1+/-0.64 ticks/animal). M. anisopliae was re-isolated from 8.9% of the ticks collected from IMI386697 treated cattle as compared to 2.8% of ticks from ARSEF3297 treated cattle.
进行了实验，以确定能够在牛体表温度下生长的绿僵菌分离株在实验室和田间研究中是否对微小牛蜱具有致病性。监测了牛体表的昼夜温度波动。测定了绿僵菌分离株（ARSEF3297和IMI386697）的温度耐受性，并在标准生物测定温度（28摄氏度）和与牛体表相似的温度（31 - 35摄氏度）下比较了它们对微小牛蜱的致病性。确定了这两种分离株在田间条件下对牛身上微小牛蜱种群的影响。荷斯坦杂交牛的前乳房、后乳房、肋骨和颈部区域的温度在30至35摄氏度之间波动，与当时的环境温度模式相似。然而，耳朵（28 - 35摄氏度）和脊柱（30 - 41摄氏度）的温度波动更大。随着温度升高，两种分离株的菌落半径均下降，然而，在34摄氏度时，IMI386697的生长速度比ARSEF3297快五倍。在28摄氏度时，两种分离株对微小牛蜱的致病性相似，然而，在31 - 35摄氏度时，IMI386697比ARSEF3297更具致病性。与对照制剂相比，两种分离株均减少了牛身上的微小牛蜱种群数量。然而，IMI386697（8.5±0.64只蜱/动物）比ARSEF3297（19.1±0.64只蜱/动物）使蜱数量减少得更多。从接受IMI386697处理的牛身上采集的蜱中，8.9%重新分离出了绿僵菌，而从接受ARSEF3297处理的牛身上采集的蜱中，这一比例为2.8%。
