Virus Ecology is a field that is gaining momentum, fueled in part by metagenomic studies from many environments previously ignored. Biodiversity studies of plant viruses show that they are abundant in wild plants, most are new to science, and most have persistent life-styles, meaning that they maintain their infection for many generations and lack horizontal transmission. Viruses are often mutualistic in plants, as are the viruses of the fungal endophytes that colonize plants. These relationships are especially important in extreme environments, where viruses can be critical for the survival of plants. New understanding about the complexity of virus-host interactions that involve plants and insects show that viruses can manipulate the activities of insects that are vectors and pollinators. These studies are giving us a new appreciation for the importance of viruses in life on earth.