Insect Net For Poly House Insect Net For Poly House is also used in green house & nethouse. Pests and insects cause immense damage to the yield by feeding on or sucking the plant, depositing eggs on the crop and spreading disease. If you’re growing vegetables, you might want to try an insect net for your Polyhouse. One of my favourite ways to use these is as a way to deter birds from feasting on my edible plants.