Flies carry many different diseases which can affect humans as well. There are over 85,000 species of flies. Live in ripe fruits , garbage, and rotting vegetables. Proper cleaning of the area is important here. Keep Garbage can tightly covered and remove all rotting materials.
Maggots can cause damage to root systems.
Soft-rot usually follows. Maggots winter in soil. Prefers garbage, manure rotting fruits, vegetables. Attracted to tree sap and fermenting fruit, are predaceous and feed on aphids, mealybugs and other insects. Parasitic on other insects.