 Other members of the class can infect plants, such as "Burkholderia cepacia" which causes bulb rot in onions as well as "Xylophilus ampelinus" which causes necrosis of grapevines.Various human activities, such as fertilizer production and chemical plant usage, release significant amounts of ammonium ions into rivers and oceans.Ammonium buildup in aquatic environments is potentially dangerous because high ammonium content can lead to eutrophication.