Leafhoppers (Homoptera: Cicadelliadae) associated with potatoes in Alaska: species composition, seasonal abundance, and potential phytoplasma vectors.

Authors: Pantoja, Alberto; Hagerty, Aaron; Emmert, Susan; Munyaneza, Joseph - Joe

Submitted to: American Journal of Potato Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/14/2008
Publication Date: 12/31/2008
Citation: Pantoja, A., Hagerty, A.M., Emmert, S.Y., Munyaneza, J.E. 2008. Leafhoppers (Homoptera: Cicadelliadae) associated with potatoes in Alaska: species composition, seasonal abundance, and potential phytoplasma vectors. American Journal of Potato Research. 86(1):68-75.

Interpretive Summary: In the conterminous USA, the presence of viral diseases, phytoplasmas, and their insect vectors are considered severe limiting factors for seed potato (Solanum tuberosum L.) production. Diseases caused by phytoplasmas have become increasingly important in the Pacific Northwest, with recent outbreaks of potato purple top disease in Washington and Oregon causing severe yield losses and reduction in tuber quality in potato. In the Columbia Basin, the potato purple top disease is associated with the Columbia Basin purple top phytoplasma vectored by the beet leafhopper, Circulifer tenellus Baker; while in Mexico and other potato producing areas of the US, purple top is associated with aster leafhoppers in the genus Macrosteles. In Alaska, potato production accounts for 14% of total agricultural crop revenues and 60% of revenues from vegetables. All potatoes produced in Alaska are used for seed or fresh consumption within the state. However, Alaska is being considered as a major potential seed potato production area for export. Due to its geographical isolation and climatic constrains, Alaska is considered relatively free of diseases and insect pests. Many potato diseases and insect pests common to North America have not been reported in Alaska. However, the biology of agricultural insect pests in the circumpolar region is lacking or poorly understood. The development of a seed potato industry in Alaska is dependent on the effective management of diseases and insect vectors. Information on taxonomic identity, biology, population dynamics, and geographical distribution of the insect pests is important in the development of integrated pest management programs. This research was initiated to study the leafhoppers associated with potato production in Alaska. Thirty-three leafhopper species were associated with agricultural settings. Fourteen species were associated with potato. Fifty-four percent of the specimens examined were collected from conventional farming as compared to 46% from the low input farming systems. Two species made up approximately 60% of the total number of individuals collected. Four of the species collected are known vectors of phytoplasma diseases of potatoes and other agricultural crops, or have the potential to cause mechanical damage to potatoes.

Technical Abstract: 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 33 leafhopper species associated with agricultural settings. Fourteen species were associated with potato: Balclutha punctata (F.), Cazenus xanthoneurus (Fieber), Davisonia snowi (Dorst), Dikraneura ossia Beirne, Draeculacephala angulifera (Walker), Draeculacephala borealis Hamilton, Limotettix corniculus (Marsh), Sorhoanus flavovirens (Gillette & Baker), Macrosteles facifrons (Stål), Paluda gladiola (Ball), Psammotettix confinis (Dahlbom), Scaphytopius acutus (Say), Streptanus spp., and Diplocolenus evansi (Ashmead). Fifty-four percent out of 53,145 specimens examined with yellow adhesive cards were collected from conventional farming as compared to 46% from the low input farming systems. Two species, M. fascifrons and D. snowi made up approximately 60% of the total number of individuals collected, representing 25% and 34% respectively. Twenty-four percent of the specimens were immature or could not be identified. Four of the species collected are known vectors of phytoplasma diseases of potatoes and other agricultural crops, or have the potential to cause mechanical damage to potatoes.