Fenvalerate and diazinon resistance in Rhipicephalus microplus ticks collected from North-Western Himalayas, India

The study was conducted to evaluate the resistance status against fenvalerate and diazinon in Rhipicephalus microplus ticks collected from five districts of north-western Himalayan region of India using Adult immersion test. Resistance factors (RFs) were calculated between 1.06 to 3.33 for fenvalerate and 2.01 to 3.83 for diazinon. Resistance to fenvalerate was detected at level I in three isolates while two isolates were susceptible. Resistance against diazinon was found at level I in all the isolates examined. Ticks from plains and low altitude areas showed higher RFs wherein intensive animal husbandry practices were followed and the use of chemical acaricides was widespread in comparison to high altitude areas. Data generated on fenvalerate and diazinon resistance status of ticks in north-western Himalayan region will provide new insights in acaricidal resistance particularly from remote areas of this region and will help in formulating suitable control measures.