Possible Perfume to Deter Mosquito Bites

Every time we exhale carbon dioxide, we are attracting female mosquitoes. However, there might be a new way to prevent mosquitoes from biting by overloading the nerve cell that detects carbon dioxide. According to Nature (http://dx.doi.org/10.1038/nature10081), Stephanie Lynn and Nan Li from the University of California-Riverside, have found a combination of chemicals (2,3-butanedione or diacetyl) that prevent the female mosquito from finding hosts. Diacetyl smells like butter or cheese and it causes the mosquitoes’ nerve cell to continue to fire so it can not find the source of carbon dioxide. Instead, the female flies in a random pattern.

There are several advantages of using these chemicals, such as they do not have to be applied directly to skin and the chemcials can be blown over a large area to protect many people. In addition, these chemicals do not interfere with DEET, so the two chemicals can be used at the same time. Currently, diacetyl is found in some alcoholic drinks and it is used to give margarine and popcorn a buttery flavor. However, when it is used at high levels, it can be an irritant and has been linked to a lung disease called bronchiolitis obliterans also known as “Popcorn Worker’s Lung.”

Female mosquito feeding. Photo by Texas A&M University.

What Is Making You Itch This Summer?

As we begin to be more active outdoors, we need to remember to protect ourselves from chiggers, which are small red mites. Chiggers develop through four lifestages: egg, larva, nymph and adult. Six-legged larvae hatch from eggs and climb up onto vegetation, so they can crawl onto a passing host. This is the only stage that feeds on humans and animals. Chigger larvae prefer to bite people in places where clothing fits tightly over the skin such as around the waistline, under socks, or where the skin is thin or creased such as around the ankles or the back of knees. Chigger larvae insert their mouthparts into a skin pore or hair follicle, and then inject a digestive fluid to dissolve skin cells. This results in itchy, reddish welts on the skin. After feeding, the larvae drop off of the host to molt into eight-legged nymphs which then molt into adults. Chigger nymphs and adults feed on eggs of springtails, isopods, and mosquitoes. Under favorable conditions, most chiggers complete their development from egg to adult in 40 to 70 days.

Suggestions for Prevention of Chigger Bites:

Avoid sitting on the ground when camping, picnicking, or working outdoors. Wear tightly woven socks, long pants, long sleeved shirts, and high shoes. Also tuck pant legs inside boots and button cuffs and collars as tightly as possible to prevent chiggers from climbing inside your clothes. Apply repellents such as DEET or permethrin to both the skin and clothing. Powdered sulfur is another repellent that can be dusted around the opening of your pants, socks, and boots or rubbed on skin such as over legs, arms and waist.

Suggestions for Relief After Exposure to Chiggers:

Wash clothes in hot, soapy water to kill chigger larvae. Take a hot bath or shower and soap repeatedly; creams or ointments such as hydrocortisone or calamine lotion can be applied to relieve itching temporarily.

Suggestions for Use of Insecticides:

Chiggers sometimes become a problem in home lawns, so chemical control may be needed. Insecticide sprays may provide some temporary reduction of chiggers and they are effective when applied in areas where chiggers and their animal hosts are living and/or traveling. Insecticides containing carbaryl, permethrin, cyfluthrin are some suggestions for control.

Photo of chigger bites. Photo by Michael Merchant, Professor and Extension Entomologist, Texas A&M University.

A New Use for Bee Venom

According to Discover Magazine (Reference: Daniel A. Heller, George W. Pratt, Jingqing Zhang, Nitish Nair, Adam J. Hansborough, Ardemis A. Boghossian, Nigel F. Reuel, Paul W. Barone, and Michael S. Strano. Peptide secondary structure modulates single-walled carbon nanotube fluorescence as a chaperone sensor for nitroaromatics.), a new bomb detector may come from bee venom. A team of researchers from MIT have used fluorescent carbon nanotubes and venom proteins to bind to single molecules of explosives, such as TNT. This causes the tubes to change the wavelength they emit so they change color to become detectable. Right now, the color change is only visible with a specific microscope, so is still more work that needs to be completed before commercial applications are possible.

Female Mosquitoes Are Out for a Meal

The female mosquito consumes blood in order to develop her eggs, which causes her to be one of the biggest medical threats to humans, since she is capable of transmitting many viruses including West Nile virus, Eastern Equine Encephalitis, and Yellow Fever. Applying repellents onto our skin is very important as we begin to enjoy outdoor activities. There are many excuses for not using repellents such as it doesn't smell good, it's too expensive, but the bottom line is that repellents are needed to prevent illnesses from a feeding female mosquito.

Some Options to Prevent Mosquito Bites:
1) Repellents can be applied to the skin and clothes to prevent bites. There are many mosquito repellents on the market such as those containing DEET, picaridin, oil of eucalyptus, and soybean oil-based repellents.
2) Avoid wearing dark colors, since mosquitoes rely on visual cues to locate hosts.
3) Avoid exercising or yard work in the heat of the day, since mosquitoes are attracted to carbon dioxide and perspiration.
4) Avoid wearing fruity or floral fragrances in perfumes, hair products, or sunscreens, since these scents are more attractive to mosquitoes.
5) Wear long, loose-fitting clothing avoid mosquito bites.

Some Options For Controlling Mosquito Populations Outdoors:
1) The number one way to reduce mosquito populations is source reduction!!! Mosquitoes need as little as a bottle cap full of water, in order to complete their lifecycle. If standing water is eliminated, then the overall mosquito population in your area will be reduced.
A) Areas containing water should be changed once a week or emptied, such as wading pools, buckets, bird baths, pet dishes, ponds, boat covers, and irrigation systems.
B) Holes or depressions in trees should be filled with sand or mortar.
C) Leaky pipes should be repaired.
D) If standing water can not be drained, then mosquito dunks containing Bacillus thuringiensis israelensis (Bti) can be used to kill the mosquito larvae.
2) Mow tall grass and reduce the amount of foliage. This will reduce the number of resting sites for adult mosquitoes.
3) Insecticides can be applied to trees and shrubs, such as those containing pyrethrins, to kill adult mosquitoes when they rest.

Photo of an Asian Tiger Mosquito. Photo by Texas A&M University.

Research on Bee Health

According to Washington State University (http://wsutoday.wsu.edu), research has been conducted on the effects of pesticide residue on honey bees. They found that low levels of pesticides build up in honey bee brood comb wax, which causes delayed larval development and a shortened adult lifespan. The pesticides involved in the study include those used by beekeepers, growers and homeowners, such as miticides, insecticides, fungicides and herbicides. The pesticide residue contamination in the brood comb may play a role in losses associated with colony collapse disorder (CCD).

Honey bee, Apis mellifera Linnaeus (Hymenoptera: Apidae), colony with queen. Photo by Bart Drees, Professor and Extension Entomologist, Texas A&M University.

May and June Beetles Emerging Soon

During the months of April and May, we begin to see the adult May and June beetles (Phyllophaga spp.) flying around lights or onto window screens, most commonly at night. The female May beetle will usually deposit eggs into the turf in April-May; where as the June beetle will usually deposit eggs in May-June. The eggs will hatch into grub worms that are creamy white in color with brown heads and are “c-shaped.” The grubs feed on dead organic matter and then move to the roots of plants. Since the grubs feed on roots, they can injure roots of grasses and other plants. This causes infested grass to brown and easily removed in large clumps.
Before treating for grub worms, lawns should be inspected to determine the presence of an infestation, which is more than 5 grubs within a square foot. In order to inspect an area, soil sections that are 3 to 4 inches deep should be taken randomly to total one square foot. One square foot of turf can be sampled by removing four, 6 inch square pieces of turf or ten, 4 inch cup cutter core samples. The optimal time for inspection and treatment should be 5-6 weeks after the most beetles are seen. This will ensure that smaller grub worms that are less than ½ inches will be found in the turf.

Some Control Options:

Non-Chemical Control Options:

Maintain healthy turf by fertilizing and watering properly.

Parasitic nematodes in the genera Steinernema and Heterorhabtitis have been shown to be effective against white grubs. They can be purchased and applied to infested areas.

Chemical Control Options:

Irrigating the soil with ¼ -½ inches of water prior to treatment can improve the effectiveness of the insecticides, since the grubs will move closer to the soil surface.
Imidacloprid, halofenozide, thiamethoxam, and clothianidin are some active ingredients found within insecticides that are often applied before extensive grub worm damage is seen, since they are effective on smaller grubs. Lambda-cyhalothrin and trichlorfon are some active ingredients within insecticides that are used when larger grub worms are present.

White grubs. Photo by Texas A&M University.

Solutions to Your Fire Ant Problems

Please join us on Thursday, April 21st from 10:00‐11:00 AM central time for a free webinar about controlling fire ants. This webinar is brought to you by The Imported Fire Ant eXtension Community of Practice. The moderator for the webinar is Dr. Kathy Flanders from Auburn University and the topics to be discussed are: How Can You Tell if You Have Fire Ants? by Dr. Jason Oliver from Tennessee State University; Understanding the Biology and Behavior of Fire Ants Makes it Easier to Control Fire Ants by Dr. Timothy Davis from Clemson University; Managing Imported Fire Ants by Dr. Bastiaan Drees from Texas A&M University and Biological Control of Fire Ants by Dr. Lawrence Graham from Auburn University. It is easy to participate; all you need to do is log in as a guest at: http://connect.extension.iastate.edu/fireant.

Photo of a fire ant mound. Photo by Bart Drees, Professor and Extension Entomologist, Texas A&M University.