Midges are tiny biting flies that are active from mid-May to September particularly when it is calm and overcast. They are a significant annoyance to people exploring the hills and to the animals that live there.
There is no known disease transmission from midges to people in Ireland. However, they will provoke a strong immune reaction in some individuals. This may lead to swelling and intense itching around the site of the bite. The severity and intensity of biting accentuates people's discomfort. Scratching of the bites may lead to infected sores.
Midges tend to proliferate around stagnant water and bog pools and are therefore a feature of life in the hills. They can also be a pest in the valleys such as Glendalough. Midges are most active on calm, cloudy and moist days. They don't like strong sunlight, dry air or wind. They tend to be most active at dawn and dusk but can be prevalent at other times during the day if the conditions are right. If it is a 'midgy' day then activities such as picnics should be avoided. Staying in one place will quickly result in midges congregating around you.
There are repellents available in supermarkets and chemists, which help deter them. Most of these will contain a chemical component called "DEET". Herbal repellents contain extracts such as bog-myrtle and citronella. In general, to protect against midges whilst walking wear full arm and leg cover and a hat preferably of a light colour - midges are attracted to dark colours to rest on. Midges can also be kept off by using a head-net which has been designed for midges - mosquito nets are not good enough. Nets are unaffected by perspiration and do not require a chemical repellent, but they can cause a headache through eyestrain. Dark nets are best for viewing through.
The midges of most interest to us are those of the genus Culicoides . There are 29 species in Ireland, including six that will bite people. The most significant nipper is Cuculiodes impunctatus. It is only the female midge that bites, doing so to extract protein from our blood, which will help develop their eggs. While most midge species are intolerant to direct sunlight there is one Culicoides heliophilus which will emerge on sunny days.