The New York State Department of Agriculture and Markets and Cornell Integrated Pest Management (Cornell IPM) are warning livestock producers about the growing threat posed by the invasive Asian longhorned tick, urging farmers to take preventative measures to protect their animals.
First identified in the United States in 2017 in New Jersey, the Asian longhorned tick has steadily expanded its range and is now becoming a significant concern for livestock health in New York’s Hudson Valley.
Officials say the tick can reach extremely high numbers on individual animals, causing substantial blood loss that may lead to anemia, reduced productivity, and, in severe cases, death. The tick is also capable of transmitting the parasite that causes theileriosis, a disease that can result in reduced milk production, weakness, weight loss, fever, pale or jaundiced mucous membranes, and death.
Theileriosis has now been detected in cattle in the Hudson Valley, and state officials report at least one livestock death in the region linked to the disease.
While cattle are most affected, sheep and goats can also become infected and serve as asymptomatic carriers of the parasite. Swine are not susceptible to theileriosis.
Unlike blacklegged ticks and American dog ticks, which are often concentrated near wooded areas, Asian longhorned ticks can thrive in open grassy pastures, making them especially challenging for livestock producers to manage.
Recommended Prevention Measures
Agriculture officials recommend several steps to reduce the risk of infestation and disease transmission:
- Ensure newly introduced animals are free of ticks.
- Screen new cattle for theileriosis before adding them to a herd.
- Monitor livestock regularly for signs of ticks or illness.
- Consult veterinarians regarding testing and treatment options.
- Implement integrated pasture management strategies.
Herd Testing and Monitoring
Producers are encouraged to work closely with veterinarians to determine herd infection status. Testing is especially important when purchasing animals from regions where theileriosis is already established, including parts of the southern and southeastern United States.
Pasture Management
If a pasture becomes heavily infested with Asian longhorned ticks, allowing the area to rest for a year may help reduce tick populations. Maintaining pasture edges by mowing and removing shrubs and brush can also limit suitable tick habitat.
Officials recommend paying particular attention to high-traffic areas such as gates, feeding stations, water sources, and livestock handling areas by keeping vegetation trimmed and controlled.
Broadcast spraying of pastures is generally not recommended because it has limited effectiveness against Asian longhorned ticks and may negatively impact beneficial insects and pasture ecosystems.
Animal Treatments
Applying approved acaricide products directly to livestock remains one of the most effective methods of controlling Asian longhorned ticks.
Ear tags may provide some protection around the head and ears but do not adequately protect the entire animal. Producers using ear tags should rotate active ingredients between years, avoid changing products during the same season, and carefully follow label instructions.
Tick Range Expanding in New York
State officials report that established Asian longhorned tick populations have continued spreading throughout the Hudson Valley. During the 2026 season, populations have been confirmed as far north as the Kinderhook area in Columbia County, with some livestock herds experiencing high infestation rates.
The ticks are difficult to detect because of their small size. Adult Asian longhorned ticks typically measure just 2 to 3 millimeters long and 1 to 2 millimeters wide, often appearing as tiny brown specks. Nymphs and larvae are even smaller.
Agriculture officials are encouraging livestock owners across New York to remain vigilant and take proactive steps to prevent infestations as the invasive tick continues to expand its range.
