Black beetle is a pest in the upper North Island. It is found mainly on light, free-draining ash and peat soils in Waikato, Bay of Plenty, Northland and coastal Taranaki and Hawkes Bay.
In most areas, populations are generally low during non-outbreak periods but numbers increase rapidly in times of outbreak (such as the one that started with the 2007/8 drought) and often stay high for several years.
Root feeding larvae are capable of severely damaging grasses in summer and autumn leading to plant death and pulling. Adults cause damage to establishing grass and young cereal crops by feeding below ground on the base of the stems, destroying the growing point and killing the tillers. Legumes are not affected by black beetle.