ORIGINALLY WRITTEN CYNTHIA MARTENS
Gardens grow resplendent in recent rains, and waxy-green grass flourishes tall and lush, but summer weather brings out more than attractive flora. It also cultivates warm-weather pests.
Try to answer the following true or false questions about one pesky little summer-time critter-the chigger-and test your knowledge of those little guys that “bug” you so much:
A) Chiggers burrow under the skin and reside beneath the surface.
B) Chiggers feed on the blood of the host animal.
C) Chiggers are mites related to ticks and spiders.
D) Chiggers can be killed by putting clear nail polish over the welt they cause.
Only C is true. The other three statements are commonly held myths about the chigger, which is the larva of the harvest mite, also called scrub mite.
“They’re a pest,” said Lou Greenhaw of Greenhaw Pharmacy in Hillsboro. “And the No. 1 thing to do to prevent them is to use insect repellents anytime anyone goes out.”
Chiggers belong to the harvest-mite suborder prostigmata. They go through four biological stages-the egg hatches as a red spindly legged larva, develops into a nymph and finally becomes an adult mite.
The eight-legged adult is not the problem for humans or animals. The culprit is the tiny, hairy six-legged larva that causes the welts and itching.
The nymph and adult harvest mites feed mostly on plant life and don’t bother people or other mammals.
But in the larval stage, they are parasites.
As larvae, chiggers are less than 1/150th of an inch in diameter and almost invisible to the human eye.
As many as 400 chiggers can be laid by one female, usually choosing damp but well-drained sites. One generation hatches each year, and can be most abundant in July, August and early September.
When the chigger hatches, the larva takes up residence on tall grass or other plants, waiting for a host to brush by so it can attach to the unwary victim until it eventually gets enough nourishment to grow into the nymph stage.
Chiggers do not burrow under the skin as many people have been told, according to the Web site www.conservation.state.mo.us.
This myth is believed to have its roots in the southern states, where a pest with a similar name, the jigger flea or chigoe, attacks by burrowing under the skin.
Chiggers bite by inserting specialized mouth parts into skin pores or hair follicles and then feeding on fluids in the skin cells.
Digestive enzymes in the chigger’s saliva hardens the surrounding skin tissue and irritates it, causing an allergic reaction-an itchy-red welt that can last for days if untreated.
For the first one to three hours, the chigger is unnoticed by its host until the skin reacts to the enzymes. If left alone, the chigger could feed for three or four days, in a cycle of injecting saliva and sucking the liquefied tissue, according to the conservation Web site.
“On human hosts, chiggers seldom get the chance to finish a meal. The unlucky chigger, that depends on a human for its once-in-a-lifetime dinner, is almost sure to be accidentally brushed away or scratched off by the victim long before the meal is complete.”
The worst itching occurs one to two days after being bitten. The hardened cells of the welt eventually disappear in seven to 10 days.
Unlike the tick, chiggers do not wait quietly for a host and are, instead, actively moving toward any new object around them.
“In terms of trying to reduce your population (of chiggers), we tell people to keep their lawn grass cut short,” said Rickey Roberts, Marion County extension agent.
“And there are some sprays that you can apply to help try and control the population as well, like insecticides.”
Outdoor sprays of chlorpyrifos found in Dursban, and carbaryl found in Sevin as well as diazinon will give some amount of control.
“And always, always follow recommended label instructions,” Roberts said.
A single application during late April or May is usually effective, and may need to be repeated in June.
But Roberts cautioned that fighting chiggers by maintaining short grass and applying insecticides only helps reduce the population, not wipe it out entirely.
When working or relaxing in a grassy area, some precautions can be taken to protect against a chigger assault.
“People just don’t seem to think they need insect repellents for chiggers like for mosquitoes,” said Greenhaw. “But actually, spraying your legs and ankles really well with insect repellent helps.”
And wearing the right kind of clothing helps, too.
“Shorts, sleeveless shirts and sandals are nearly suicidal in chigger-infested areas,” according to the conservation Web site.
“Wear tightly woven socks and clothes, long pants, long-sleeved shirts, and high shoes or boots. Tucking pant legs inside boots, and buttoning cuffs and collars as tightly as possible also helps keep the wandering chiggers on the outside of your clothes.”
After spending time outside, take a bath or shower as soon as possible using warm soapy water to prevent the little pests from finding a semi-permanent home on your skin.
“A bath will remove any attached and feeding chiggers before you start to feel the itch,” according to the conservation Web site.
“Attached chiggers are removed by even the lightest rubbing. If you are away from civilization, you can remove attached chiggers before they do much damage by frequently rubbing down with a towel or a cloth.”
Once the enemy has taken up camp and the itching commences, many people attack their foe with a swab of clear nail polish.
“This does not kill the chigger or treat the bite in any way,” according to www.howstuffworks.
“It simply seals the area off from the air, which keeps the sore from itching so badly.”
The over-the-counter products to combat the chigger welts contain Benzocaine, a numbing agent to stop the itching, Greenhaw said.
A product called Chigger-Tox contains soft soap, Benzocaine and Benzyl Benzoate-an antiseptic.
Another alternative is to use a camphor-menthol product.
“There’s a product called Chigarid that has the camphor and menthol, and then it’s in a base called Collodion,” Greenhaw said. “The Collodion seals it off and helps with the itching.”
An antihistamine product for the itching is also available-but should be used only at night, because it can cause drowsiness.
If the welts are scratched and become infected, Greenhaw said she recommends a triple antibiotic ointment.
“If a person scratches them too much, you can get Impetigo in them,” she said. “So normally, they’re just a nuisance. But there are cases where it can get pretty bad.”
And why do some people seem more susceptible to chigger welts than others?
“We don’t know,” said Hillsboro physician Randal Claassen. “We wish we did know. Why does your neighbor get a horrible reaction to poison ivy, and you can swim in it and not have a problem?”
Claassen said his office generally doesn’t see many patients with chigger bites because they use over-the-counter treatments.
And when should someone be concerned about a reaction to the chigger bite?
“If it’s a significant reaction, and it’s not getting better,” Claassen said.
“If it’s gradually getting worse, then I’d worry about an allergic reaction that’s not under control or a secondary infection that needs to be treated.”
Before it reaches that stage, Greenhaw said she tries to stock products to reduce the itching. But when contacted one day in mid-June she was completely sold out.
“And we order every single day,”she said.
“We always have a chigger problem. And we always sell a lot of chigger products in the summer.”