Friday, June 2, 2017


SPINOSE EAR TICKS IN EDDY COUNTY The most common tick in Eddy county and New Mexico is Spinose Ear Tick, (Octobius megnini). Ticks frequently use wild animal hosts to maintain tremendous populations near treated cattle herds. Ticks produced on wildlife can re-infest treated cattle, and they continually pose a problem for Eddy County and New Mexico cattle producers. Some species of ticks are also capable of transmitting diseases such as anaplasmosis to cattle however, there is no know disease transmitted by Spinose Ear Tick. The life cycle of ticks starts out as larval ticks, which are six-legged and 0.5 mm long, hatch in three to eight weeks from eggs laid on the ground and climb anything vertical and patiently await passing potential hosts. Wooden coral posts, gates, barn siding. They can survive several months without a feed or moisture. When a suitable host becomes available, they make their way to the ear and attach just below the hairline. Grooves and folds in the ear canal are favored sites. I have dug them out from deep within the ear. After sucking blood for about a week and growing to about 4 mm they molt to the first nymph stage. The first stage nymphs remain in the ear without feeding and molt seven to ten days later to the second nymph stage. Second stage nymphs suck blood for one to seven months, growing to about 8 mm long, and it is this stage, which is most likely to be observed. They are big and plump looking. After exiting the ear and dropping to the ground, they hide in cracks, crevices, beneath rocks and under bark before maturing to adults in one to six weeks, depending on environmental conditions. Adults are free living and eat nothing. They mate on the ground and females can survive up to two years, laying 500–1500 eggs. The Spinose Ear Tick first appeared in New Mexico during the drought years of the early 1930s when Texas cattle were imported to this area to obtain water. Infestations were somewhat localized. During the 1960s, the range of infestation appeared to spread statewide. Now they in every county in New Mexico, and in every state in the Union as well as Canada, Mexico, India, and Australia. Parasitic larvae and nymphs of this species cause serious damage to livestock. The wounds can become infected with pus-forming organisms that give rise to a condition known as canker ear. The constant irritation causes animals to become dull, unthrifty and even to lose weight. Infested animals shake their heads and rub their ears in an attempt to relieve the irritation. This species of ticks are not known to be vectors of disease thankfully because they are hard to control once established in a heard. However, tick infested animals are subject to secondary microbial infections due to feeding wounds and the accumulation of tick feces and cast exuviate from molting. In addition, severely infested animals are prone to maggot infestations as a resulting from flies laying eggs in the deteriorating environment. They can but do not often infect human, dog, cats or sheep. I have found extensive populations in horses. They are reported in mules, goats, lama, elk, white-tailed deer, mule deer, mountain sheep and goats. Infestation is spread by introduction of an infested animal or animals into previously un-infested herds. Bulls and replacement heifers that are to be kept for some time are most likely to be involved. Since the nymphs may remain in the ear for four months, any animal kept on a farm or ranch for that period of time could provide the source for infestation of the whole herd. It take vigilance over a long period of time to break the life cycle and “clean up” a herd because of the long life cycle and wildlife host source. Controlling ticks is difficult and generally requires a combination of cultural, preventive, and pesticide control methods. Ear ticks on livestock can be controlled with systemic or contact insecticides. However, re-infestation makes this method expensive. Insecticide impregnated ear tags help prevent ear infesting ticks fairly well. For more information see Texas Extension publication For non-cattle infestations controlling tick-infested vegetation around the home and using contact residual insecticides in the spring on the fringe areas of the yard when ticks are most abundant reduces tick infestation of children, adults, and pets. Insect repellents for humans and shampoos or collars containing insecticide for pets can help control or reduce tick infestations. Subscribe to Eddy County Ag news at: Eddy County Extension Service, New Mexico State University is an equal opportunity/affirmative action employer and educator. All programs are available to everyone regardless of race, color, religion, sex, age, handicap, or national origin. New Mexico State University, U.S. Department of Agriculture, and the Eddy County Government Cooperating.

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