Pumpkin flies have a wingspan of 12-14 mm. These brown flies resemble wasps and have bright yellow markings on its body. The maggots that develop inside the fruit are 8-10 mm long, white to cream coloured and have one pointed (head) and one blunt (rear) end. Fully grown larvae exit the fruit to pupate in the soil.
Pumpkin fly females puncture the surface of young cucurbit fruit and lay their eggs inside. The fruit will be permanently damaged and may deform as development continues, even if no egg was laid. When larvae hatch, the fruit will rot before it matures. Pumpkin flies can attack a variety of cucurbits, with some species preferring watermelons.