Fruit flies lay eggs near the surface of fermenting berries. Eggs take only 30 hours to hatch, and larvae develop in fermenting material. They feed near the surface, mostly on yeast, for 5 to 6 days and go to drier places to pupate. The life cycle may be completed within 8 to 10 days at 85 F (29 C). Timely harvesting can help prevent fruit fly outbreaks in the vineyard.