A SPELL of good weather is a welcome addition to any Irish summer but it has drawbacks. Irritation by flies and biting insects can be a warm weather problem for horses and horse owners but the issue can be reduced by some simple management strategies.

Insects (arthropods) make up over 80% of all known species on earth and have a worldwide distribution. Flies, fleas and lice are the primary insect categories of veterinary significance but the focus here is on the flies (Diptera), of which there are over 120,000 species.