PNP: Liquid Residual is both a contact and residual insect killer. This residual spray stays on treated surfaces and kills insects after the spray dries. PNP can kill both crawling and flying insects. Some of the insects it can be used to treat includes cockroaches, ants, spiders, wasps, hornets, house flies, cluster flies and silver fish.
The benefit of using a residual spray is the fact that insects are more active when the presence of people is vacant. This means that when you are away, the insects will be more active. When used correctly, a this product can significantly reduce the population of insects. Using PNP correctly would include spraying in high traffic areas where bugs would be most prevalent. One area for cockroaches that would be beneficial to spray would be beneath the fridge and stove, for instance.