Make a midge eater


A midge eater placed beside a tree

Some parts of Scotland might be plagued by midges at certain times of the year, but this Science Bite will show you a simple, home-made way to gradually reduce the number of the biting critters in your garden.


Midge eater kit

To make a midge eater, you'll need:

  • An empty 2 litre pop bottle
  • An empty 500 ml pop bottle
  • An old sweaty sock
  • A packet of yeast
  • Water
  • Scissors
  • Dessert spoon
  • Some small pebbles (to weight the contraption)
  • Duct tape
  • Black paint (optional)


You can follow the instructions in the video below.

Can't see the video above? Watch it on Youtube.

Or, step-by-step guide...

Rinse out the 2 litre pop bottle.

For best results, at this stage you can paint the whole of the outside of the bottle black.

Using the scissors, carefully cut the cylinder about 2/3 of the way up.

Remove the bottle top and carefully make a hole in it with the scissors that's about 0.5 cm in diameter. This will allow the midges to get into the device but not easily escape. Replace the bottle top. Keep the top portion and bottle top as you will need it shortly.

Rinse out the 500 ml pop bottle.

Using the scissors, carefully cut the cylinder about 1/2 of the way up. You can recycle the top of this smaller container as you will not need it for your midge eater.

Follow the instructions on a packet of yeast (available from the home baking aisle in most supermarkets) to make up the ‘starter’.

Pour that into the 500 ml bottle along with about 150 ml of sugar syrup – made from a dessert spoon of sugar dissolved in 150 ml of water.

Make a midge eater

Carefully, pull the sweaty sock over the container so that it covers and seals the top of the 500 ml bottle.

Place the 500 ml bottle inside the 2 litre bottle. Place some small pebbles inside the 2 litre bottle around the gap between it and the 500 ml bottle. This will help to keep the bottle upright.

Invert the top portion you cut away from the 2 litre bottle and fit into the bottom portion, so it looks like a funnel. Seal the join with duct tape.

Place upright and securely in a shady, damp part of your garden, yard or field.

Make a midge eater


Midges detect their victims mostly by the carbon dioxide they emit when they breath out. The yeast in the sugar solution turns the sugar into carbon dioxide (and alcohol!). The carbon dioxide wafts out of the top of the container in a way almost irresistible to midges. They fly in but can’t find their way out again and eventually die.

Midges are attracted to the trap, so don’t put it where humans are going to be – instead place it 8-10 meters away. You can make a ring of 5 or 6 midge eaters to create an exclusion zone. Midges prefer dark colours and shade, so painting it black increases the effectiveness. Midges tend to be quite territorial which means they tend to live and hunt in a small area. You should then see the population decreasing. You will need to stay on top of this by checking the mixture now and again because the yeast will eventually die and the mixture need to be replaced.

Should we kill midges?

Midges are an itchy nuisance, and some can carry animal sicknesses. Scotland has a huge midge population thriving in the humid and temperate climate. Midges are an important part of the food source for some birds and bats, as well as other predatory insects

Scottish Midge Forecast

The Scottish Midge Forecast maps midge levels across the country - useful if you're heading out and about in the great outdoors.

Send us pictures if you try this Science Bite for yourself. Tweet your pics to @GSC1 or post them on our Facebook timeline.

Curriculum Links

Biodiversity and Interdependance

SCN 2-01a/ 3-01a


Glasgow Science Centre