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. I don’t like it when they peck holes into my tomatoes and raspberries; I cover them with nets and make sure nothing can touch them.