Mosquito Myth Busters

Listerine as a pesticide

The Claim - received via email:

How to Kill Mosquitoes - NOT A JOKE

You may be aware of this, How to Kill Mosquitoes - NOT A JOKE
I can't wait to try this in the summer!

I was at a deck party awhile back, and the bugs were having a ball biting everyone.  A man at the party sprayed the lawn and deck floor with Listerine, and the little demons disappeared.  The next year I filled a 4-ounce spray bottle and used it around my seat whenever I saw mosquitoes.  And viola!  That worked as well.  It worked at a picnic where we sprayed the area around the food table, the children's swing area, and the standing water nearby.  During the summer, I don't leave home without it....Pass it on.

OUR FRIENDS'S COMMENTS:  I tried this on my deck and around all of my doors.  It works - in fact, it killed them instantly.  I bought my bottle and it cost me $1.89.  It really doesn't take much, and it is a big bottle, too; so it is not as expensive to use as the can of Bug-spray you buy that doesn't last 30 minutes.

So, try this, please.  It will last a couple of days.  Don't spray directly on a wood door (like your front door), but spray around the frame.  Spray around the window frames, and even inside the dog house.

Now these are Good Mosquitoes!!!  EARTH FRIENDLY TOO???

 

The Stage:

  • ​Mosquito Cage
  • Listerine Bottle
  • Spray Bottle
  • Several hundred Quinks

The Experiment:

Hypothesis:

Listerine serves as an alternative and effective pesticide for mosquitoes.

Materials and Methods:

For this experiment, quink larvae were collected from within the district and reared in an insectory under warm, moist conditions. The mosquitoes were fed liver powder as larvae and diluted sugar water as adults. After about one week, there were sufficient numbers to conduct the experiment. A blank sheet of paper was placed in the bottom of the cage in order to more effectively see any mortality.

Results:

The first test consisted of one spray of Listerine. No mortality was noted after the elapsed time of five minutes. The second test consisted of two sprays. Though there were some “knocked down” initially, there was again no mortality after five minutes. The third test consisted of 4 sprays, with no mortality, though there was another initial knockdown. The final test, or the “saturation test” included 20 sprays. Though there was a large initial knockdown, there was no mortality after five minutes. The next day the mosquitoes were observed, and there was no mortality noted during that period as well.

Conclusion:

Listerine is an ineffective pesticide to use against mosquitoes. While it may seem to kill them initially, those mosquitoes have a high probability of recovering. The initial knockdown is most likely due to the mosquitoes getting wet from the direct spray. Once the wings dry, they may recover and resume flight.

The Movie:

Dryer sheets repel mosquitoes

The myth - Dryer sheets repel mosquitoes:

Many citizens have questioned if dryer sheets really work for keeping mosquitoes away. During classroom visits, I have often been told by students that several of their family members swear by this method. For this Mosquito Mythbusters topic, we decided to test this in a laboratory setting.

The Experiment:

Hypothesis:
Dryer sheets are no more effective than a repellent.

Materials and Methods:

We used an insect cage in our laboratory insectory which contained various mosquito species. These species included: Aedes albopictus (Asian Tiger mosquito), Coquillettidia perturbans (Salt and Pepper mosquito) and Anopheles crucians. The mosquitoes were collected from areas within our district from containers and places containing floodwater. These species tend to be more aggressive to humans; therefore, they were the better choices for this experiment. The mosquitoes were kept in a warm and humid environment and fed a sugar water solution.

Repellents:

  • OFF Smooth and Dry: 15% DEET (the active ingredient)
  • Repel Sportsmen: 29% DEET
  • Repel Sportsman Gear Smart Formula: 15% picaridin
  • Downy dryer sheets


Landing rates were taken for a control, the dryer sheets, and the repellents for one minute. Mosquitoes were counted if they landed or attempted a blood meal. The dryer sheets were rubbed all over the arm and then held in the hand once inserted into the cage. Each repellent was applied after a thorough washing of the arm and applied in two sprays.

Results:

This test was performed twice, these data are from both tests combined.

Control (no repellents or dryer sheets used): 4

Dryer sheets: 3

Repel Sportsman Gear Smart Formula (15% picaridin): 0

OFF Smooth and Dry (15% DEET): 0

Repel Sportsman (29% DEET): 0

Conclusion:

The dryer sheets are ineffective at repelling mosquitoes, though one less mosquito was recorded landing when the sheets were used. Proper repellents should always be used according to their labels as they are the most effective way to repel mosquitoes. An improvement on this test in the future would be to collect more mosquitoes, though in general these species are difficult to locate in breeding sites and rear in the lab.

The salt shotgun is effective at killing adult mosquitoes

The myth - received from curious citizen:

The idea for this myth was brought to our attention by a curious citizen who stumbled upon this website. The Bug-A-Salt shotgun claims to efficiently kill flies, mosquitoes, wasps, and roaches with ordinary granulated table salt.

 Materials and Methods:

For this test, we used an insect cage containing Culex quinquefasciatus (southern house mosquito) larvae and adult mosquitoes. The mosquitoes were collected from various septic ditches from within our district, fed a sugar water solution, and kept in a warm, humid environment within the insectory. Blank white sheets of paper were attached to the back and bottom of the cage in order to effectively observe mortality. Morton brand table salt was used in the shotgun. A small amount of salt was added to the lift cap before the test.

Features and shotgun composition:

  • Non-toxic
  • No batteries
  • Inexpensive
  • Approximately 50 shots after being fully loaded
  • Safe (do not point at face)

Results:

The shotgun was used on individual mosquitoes and a group of mosquitoes in a small container. Both shots fired on the individual mosquitoes resulted in instant mortality with no observed "splatter". Three consecutive shots were fired on the small container of mosquitoes. Some were stunned with each shot, and at the end of three shots about eight were killed out of 14 mosquitoes.

Conclusion:
CONFIRMED

The makers of the gun never claimed to efficiently kill multiple insects in one shot; therefore, this myth is confirmed. The salt shotgun is effective at killing individual adult mosquitoes, with no "splatter" and very little cleanup.

While the "Bug A Salt" can, in fact, kill mosquitoes, the effective range is very limited (nearly point blank shooting is required). Therefore, we consider the item more of a curiosity and cannot recommend its use as an actual control device.

Picture courtesy of https://www.bugasalt.com/

For further information on the salt shotgun, visit: www.bugasalt.com

The Movie:

Repellents and Bite Relief

The Question:

Are these products effective at repelling mosquitoes and/or relieving bites?

The idea to test these products have come from questions from curious members of our community and from online investigation. We have collected a repelling bracelet, an insect repelling essential oil, and a bite remedy for further testing.
Materials and Methods:
 

For this test, we used an insect cage containing various floodwater mosquito larvae and adults. Mosquitoes that live in a floodwater environment are generally more aggressive and more likely to attempt a blood meal. The mosquitoes were collected from various breeding sites from within our district, fed a sugar water solution, and kept in a warm, humid environment (about 85 F degrees and 70% humidity) within the insectory.

Repelling Products:

MosquitoNo brand wristband

  • Contains citronella oil
  • Non-toxic
  • Waterproof
  • Safe for children 3 and up
  • Light, inexpensive, resealable packaging

Plant Therapy Essential Oil

  • Contains: citronella oil, Eucalyptus globulus, cedarwood, lemongrass, lavender, may chang, tea tree oil, patchouli and catnip
  • Generally positive reviews online
  • Can be applied either directly on clothes and skin in a dilution or used in a diffuser

Two different solutions were made to see if the carrier liquid also played a part in repelling mosquitoes. Witch hazel and apple cider vinegar (figure 1) have been shown to be effective carriers for the oil, so these were chosen. Both were mixed with the same dilution of 5% (30 mL of carrier liquid, 30 drops of oil) in 2.4 ounce spray bottles (figure 2).

Bite Relief:

Zap-IT! mosquito bite relief

  • Delivers a small electric current directly on the mosquito bite, claiming to offer relief from itching and swelling.
  • Place directly on the bite to administer the current.

To test these products, Colby's arm was inserted into the rearing cage, first with no product as a control, followed by the bracelet, and two mixtures of essential oil. Her arm was thoroughly cleaned between each test. Landing rates were taken by timinmg one minute, and counting how many mosquitoes attempted a blood meal during that time. This was repeated twice more and an average was taken for each product and control. The Zap-IT! bite relief was used on one mosquito bite obtained during the test.

Results

Average Landing Rate

Control (no product)

8.00

Bracelet

3.67

Oil with Witch Hazel

1.67

l with ACV

Conclusions for Bracelet and Essential oil:


CONFIRMED

The MosquitNo bracelet and both mixtures of insect essential oil seemed to repel mosquitoes when compared to no repellent at all. The essential oil diluted with apple cider vinegar seemed to be the most effective as a repellent. Further testing is needed to determine how these would compare against more common repellents.

Conclusion for Bite Relief:


INCONCLUSIVE

The Zap-IT product seemed to bring slight relief to the bite, though this test is inconclusive due to only being administered to one bite. The initial shock of the current is also jarring, and it does not seem any more effective than using rubbing alcohol. Further testing will be needed to compare to rubbing alcohol.

The Movie:

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