Leafhoppers (Homoptera: Cicadellidae) Associated with Potatoes in Alaska: Species Composition, Seasonal Abundance, and Potential Phytoplasma Vectors

Leafhopper transmitted phytoplasma diseases are an emerging problem for potato and vegetable producers in the conterminous US. Due to its geographical isolation and climatic constraints, Alaska is considered relatively free of diseases and insect pests; therefore growers in the state are exploring the potential of producing seed potato for export. However, the biology of agricultural insect pests in the circumpolar region is lacking or poorly understood. Research conducted from 2004 to 2006 in the main potato (Solanum tuberosum L.) production areas of Alaska resulted in the identification of 41 leafhopper species associated with agricultural settings. Twenty species were identified from sweep net samples and adhesive cards in association with potato. Two species, Davisonia snowi (Dorst) and Macrosteles fascifrons (Stal), made up approximately 60% of the total number of individuals collected, representing 34 and 26%, respectively. Both species, M. fascifrons and D. snowi generally arrived in fields by late May to early June and numbers peaked by late June to July, but in all years M. fascifrons populations peaked earlier than D. snowi. Twenty-three percent of the specimens were immature or could not be identified. Three of the species collected [Balclutha punctata (Fabricius), M. fascifrons, and Scaphytopius acutus (Say)] are known vectors of phytoplasmas of potatoes and other agricultural crops or have the potential to cause mechanical damage to potatoes. This report represents the first extensive study of cicadellids from potatoes in Alaska.