Nature, (Adamo, S., et al) July 29, 2022, published an article on researchers finding a new natural acaracide─kills ticks. There are synthetic pesticides that can reduce tick numbers but there are environmental concerns about their effects on beneficial insects.
Ixodes scapularis ticks (blacklegged─deer tick) transmit Borrelia burgdorferi, bacteria that cause Lyme disease. These ticks overwinter by going into leaf litter, and researchers indicate these ticks can survive under leaf litter well below 0° C (32º F). Leaf litter allows nymphs/larvae to have 80%+ survival rate over the winter months.
A researcher observed that these ticks did not successfully survive under balsam fir (Abies balsamea). This study tested those fir needles and essential oils from them against overwintering ticks regarding survival of the ticks. These items killed ticks. Low temperatures may also aid in this killing process with these substances.