Baddest Bugs Quick Reference Chart
| Who | What | Why |
| Bot Flies | Bee-like flies that lay eggs on horse’s legs, chest and jaw. | Larvae are dangerous internal parasites. Horse licks eggs, larvae hatch and penetrate horse’s lips and tongue. Migrate to stomach and feed for months. |
| Chiggers | Larval form of harvest mites - external parasites. | Burrow into the epidermal tissue, causing severely itchy red bumps. Easily transmitted from horse to horse. |
| Deer Flies | Biting flies that live and breed around waste. Daytime feeders. | Very painful and persistent biters. May transmit equine infectious anemia, equine encephalomyelitis and other diseases. |
| Face Flies | Filth flies; feed on tears, mucus and saliva. | Spread disease, cause eye abrasions, transmit pinkeye and horse eye worms. Cause horses to tear excessively, become nervous and lose weight. |
| Gnats | Biting pests that breed in fast-moving streams and other wet areas. | Vicious biters that attack the inside of horses’ ears, leaving bloody crusty spots. |
| Horn Flies | Biting flies; breed in fresh cow manure. | Constant irritation to pastured horses. Can affect horse’s performance. Cause ventral midline dermatitis. |
| Horse Flies | Biting flies found in marshy areas, ponds and swamps. They breed around standing water. Daytime feeders. | Inflict painful bites and draw blood. May transmit anthrax, tularemia, anaplasmosis and equine infectious anemia. |
| House Flies | Filth flies; live and breed in manure and garbage. Daytime feeders. | Spread germs and disease. Irritate and annoy horses. |
| Lice | External parasites that feed on skin cells or blood. | Cause heavy dandruff and greasy skin. Bloodsucking lice can create bald spots and even cause anemia. |
| Mites | Almost microscopic external parasites. | Cause mange, a contagious skin condition. |
| Mosquitoes | Bloodsucking insects that breed in standing water. Most active at dawn and dusk. | Inflict painful, itching bites. Known to transmit fatal diseases including West Nile Virus and equine encephalomyelitis. |
| Stable Flies | Biting flies; breed in manure and other wet, decaying matter. Daytime feeders. | Bites are very painful. Known to transmit equine infectious anemia. Bite horse’s legs and flanks. |
| Ticks | Bloodsucking external parasites. | Transmit a number of dangerous diseases including Lyme Disease, Rocky Mountain spotted fever, Colorado tick fever, anaplasmosis, tick paralysis, equine infectious anemia and more. |
