Balmier Irish summers mean planning an outdoor party is, no longer as risky weather-wise as it used to be. But one hazard of summer days seems to be on the increase: the threat of being harassed by tiny, persistent, biting insects - midges, asks Iva Pocock

They torment far beyond their size. They never work alone, but in great clouds, emerging as the wind dies and the temperature and humidity rise.

It's the females who do the damage; the males get their food from plant nectar and rotting plant remains. Females have well-developed, specialised mouths to pierce victims' skin and suck up released blood. Then they pump saliva into the wound to prevent the blood from clotting and the flow from drying up.

The digestive enzymes in the midge saliva induces a mild allergic response causing the victim's body to respond with a rush of histamine to the wound site, causing the familiar post-bite itching and swelling.

So can you prevent them attacking you and your guests?

First, try to have a good air current, says Sean O'Gaoithin, head gardener at Glenveagh Castle, Co Donegal, who has plenty of experience in dealing with midges, as they thrive in his workplace. "Fans are a good idea," he says, as they help disperse the midge-attracting carbon dioxide which we expel as we breathe and respire through our skin.

"The problem with large crowds is that they produce larger amounts of carbon dioxide so they are a bit like sitting ducks."

Next on the list of midge weapons is smoke. "Traditionally people on the bog would light a little fire to keep them [ the midges] away." So braziers, bonfires and possibly candles, will help, as well as adding to your party's ambience."

Using repellents is also an obvious way to deter midges (and clothing impregnated with insecticide, now available in the US, may catch on here).

Billy Murphy, recreation manager with Coillte, recommends the mixture of citronella and eucalyptus contained in Green Ban repellent which he buys in the US. "You get some bites but not too many. I don't like DEET because it's an insecticide and there are a lot of question marks over it."

Many repellents such as Jungle Formula and Bens contain DEET in varying proportions, so make sure to tell your guests what you are offering them along with their drink and dinner. Eating garlic is also recommended by some.

For those keen to have a midge-free summer for more than just a day, O'Gaoithin recommends a midge-collecting machine, which can trap thousands of female midges a day, clearing up to an acre. Since investing in one mosquito magnet, made by the American Biophysics Foundation, three years ago, Glenveagh gardens now has seven machines which O'Gaoithin says have made a difference.

"Normally you couldn't stand out here in the garden yard for more than two minutes. Now we can meet here in the morning to converse and plan for the day," he says. "The downside is that they need to be running for at least six weeks before you see a significant impact."

They also need servicing and maintenance, so installing one at a holiday cottage may not be viable, as the initial outlay is about €2,000. A cheaper version is Calor's Midgeater Plus, which costs about €1,000.

"Whether it's worth buying one of these for two weeks in the year is debatable," says O'Gaoithin, who gets many calls from distraught holiday cottage owners who can't sit out during their summer break.

In Oughterard, Co Galway, pharmacist Eamonn Flaherty says many local people have invested in the machines to combat "the curse of Connemara". He is certain the midge problem has got worse since he moved there in 1998.

Locals are fighting back, and where a couple of adjacent neighbours have invested in midge machines, the blood-sucking clouds have reduced.

O'Gaoithin warns users: "Make sure you don't put the machine where you want to enjoy a barbecue; put it in the corner which is not used." His final piece of advice for beating the midges is, "Don't stay in the same place. You can move a lot faster than they can, so organise lots of dancing."