Corn flies, also known as flower flies or hover flies, are attracted to warm, muggy conditions and feed on flower pollen, including corn pollen. They are generally harmless and do not sting or bite, but can be annoying when present in large numbers. To repel or get rid of corn flies, effective strategies include:

• Using DIY traps made with apple cider vinegar, water, dish soap, and sometimes sugar, which attracts and drowns the flies.
• Maintaining cleanliness by removing overripe fruit or vegetables, wiping countertops, and dumping kitchen compost daily to eliminate breeding grounds.
• Setting vinegar traps or yeast traps outdoors or in areas where flies congregate; these traps attract flies and keep them from flying around freely.
• Reducing moisture and humidity in the affected area since these flies thrive in humid conditions.
• Keeping food covered and avoiding leaving sweets or decomposing plant material exposed.

Overall, these flies are more of a nuisance than a threat, and managing their environment with cleanliness and traps is the best approach to repel them effectively.