June 05, 2008
Watch Out for Chiggers This Summer
LINCOLN, Neb. — Ticks and mosquitoes are summer pests that usually demand attention because of their ability to spread disease. One often overlooked pest that can be as great a nuisance during the summer is the chigger mite.
Fred Baxendale, University of Nebraska-Lincoln Extension horticultural entomology specialist, said chiggers have become more prevalent within cities because of the abundance of tree squirrel and rabbit hosts.
"Squirrels and rabbits are excellent vertebrate hosts, and they readily move and can transfer chiggers from one yard to the next," he said.
Chiggers feed on vertebrate hosts, such as mice, rats, rabbits, ground and tree squirrels, and they can be found in vegetative areas where these hosts are most abundant. Humans normally are accidental hosts.
Baxendale said early-June through mid-July are the peak times for chiggers. He said the greatest number of bites are often reported during fireworks shows. The reason people get more bites at shows, he said, is apparent when one observes their behavior.
"I see folks sitting on the lawn and kids playing and rolling in the grass," Baxendale said. "I knew how they will be feeling the next day."
Baxendale recommends these steps to reduce the number of chigger bites and cut down on chigger infestations:
– Keep weedy vegetation cut back to the perimeters of the landscape. Maintaining a well-manicured lawn and landscape provides less habitat for chiggers.
– Before going out into potential chigger-infested areas, apply an insect repellent containing DEET. He said products with DEET are most effective against chiggers.
– After returning from an outing in chiggers-infested areas, take a hot shower using plenty of soap as soon as possible.
– Launder clothing rather than re-wearing it. Chiggers will climb onto trousers and clothing. If the clothing is worn again without being washed, they will move to the person and bite.
– Dogs and cats also may pick up chiggers on their body and fur and transfer them to people. "Consider bathing dogs and cats or use a repellent. Flea or tick collars also will work against chiggers," Baxendale said.
– In areas with severe chigger infestations, a range of insecticides are available that can be sprayed on turf and surrounding landscape plants. Baxendale said spraying insecticides will control chiggers for two to three weeks, and depending on square footage, most yards can be sprayed for as little as $10 to $15.
"I don't recommend pesticides, however, until chiggers have been confirmed in an area," Baxendale said.
Baxendale said a common misconception is that chiggers feed in a similar manner as ticks. Generally a chigger mite will finish feeding and drop from the host within 24 to 48 hours after initial contact.
To feed, chiggers find a hair follicle on the host and inject enzymes that break down skin tissue, allowing the chigger to suck up the dissolving tissue. This action creates the intense itching. Chigger bites are slightly larger than mosquito bites and the itching can last for up to two weeks.
Baxendale said chiggers are beneficial predators on other insects and mites during their later life stages and are harmless to humans. It is only the first larval stage that feed on vertebrate hosts.
UNL Extension is part of the university's Institute of Agriculture and Natural Resources.
6/5/06-AB
Fred Baxendale - Ph.D.
Entomology
Professor
(402) 472-8699
Sandi Alswager Karstens IANR News and Photography (402) 472-3030
Department: Entomology
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