QuestionsHow to growGreenhouse GrowingSkills of Greenhouse growingFruitflies in polytunnel 0 Vote Up Vote Down Therese Colleran asked 8 years ago I recently started composting in my polytunnel. Fruitflies have been attracted to the mound though, should I be worried about them attacking my tomato or chili plants when they bear fruit? 1 Answers 0 Vote Up Vote Down Gerry Daly Staff answered 6 years ago Fruit flies feed on over-ripe fruit and rotting fruit and will not affect grwoing tomatoes or chillies.