Flies: not the most attractive topic. But flies are an everyday part of our summer lives, and, in our yurt, we have discovered that flies can be particularly bothersome. The design of a yurt lends itself well to being a haven for these pests. The relatively loose fit of the tarpaulins allows these nuisances to squeeze themselves through crevices and cracks, while the permeability of the structure enables odours to waft outward. Combine these two factors with the tendency of the roof tarpaulin to trap the sun’s heat, and yurts become playgrounds for flying pests.
Last autumn, for example, I removed a portion of the dome insulation to install additional snow load braces, and found hundreds of dormant flies embedded in the top side of the fibreglass insulation layer. While part of the problem may have been that the eggs pre-existed in the insulation package, recent hot days have stimulated an invasion of black and bluebottle flies.
An additional contributor to the attraction of our yurt for flying insects is the presence of our grey water tanks and compost holding tank near the home. Whenever we drain or flush these systems, flies are drawn to the site.
The round design of the yurt, as well, means that there is less air turbulence, on windy or calm and hot days. This relative tranquility allows flies to gather and reproduce.
We have implemented and tested a variety of solutions. The conventional insect trap is a general failure, for flies, mosquitoes and wasps. Unfortunately, it does a terrific job on moths, which we prefer to allow to thrive.
In desperation, we resorted to commercial chemical sprays, without success, while also flooding the environment with toxins. These sprays included perimeter, spot and space sprays, all equally ineffective.
We grow such plants as tansy, lemon balm, sorrel and other natural insect repellents. They do work, but only within a very limited and defined area. We would need to plant these sentinels every few inches around the home, and even vertically on our yurt walls to have any hope of winning the insect war.
Inside the yurt, we have resealed all of the joints of the foil-backed bubble insulation that lines our yurt roof. This action has been significantly successful, as the flies that do hatch in the domed area must migrate outward, rather than inward.
Our walls have been difficult to seal completely, given the way they moor to the roofline and floor. However, taping all of these joints has been successful, as well.
A third successful solution has been to open the dome vent while closing all but two of our windows, and using our ceiling fan to draw the air upward, instead of forcing it downward. We have installed a floor vent that allows cool air from beneath the deck to be drawn upward. This continual air movement keeps the flies from settling. The round interior of the yurt maximizes air movement, which the flies dislike.
The last proven solution that we have employed is to install a small fume hood over our cook unit, and bent it outside. With less odour to attract the flies, they now prefer to congregate near the outside vent.
We are experimenting with one other solution: mustard paste. In past years, I have had great success in deterring bugs and crawling pests in the garden, by obtaining mustard seed and wild mustard screenings from a local seed cleaner. When crushed and applied near plants, insects shy away from this hotfoot compound. We have obtained mustard oil (crushed form these same seeds), and have applied a spray under the lip of the roof tarp where it meets the wall, around the base of the wall tarp and around the window and door cutouts. So far, in the areas where this oil has been applied, there is a huge reduction in fly accumulation. However, we need to observe how long this spray lasts, and whether it has a detrimental effect on the fabric. We will keep you posted!