|Munyaneza, Joseph - Joe|
Submitted to: American Journal of Potato Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/24/2013
Publication Date: 2/19/2014
Citation: Murphy, A.F., Rondon, S.I., Marchosky, R., Buchman, J., Munyaneza, J.E. 2014. Evaluation of beet leafhopper transmitted virescence agent damage in the Columbia Basin. American Journal of Potato Research. 91:101-108. Interpretive Summary: The beet leafhopper is an important insect pest of potato in the Columbia Basin of Washington and Oregon. Researchers at USDA-ARS Wapato in Washington, Oregon State University, and Frito-Lay Inc. determined the number of leafhoppers needed to cause economic loss to potato production. It was found that one to two insects per plant can result in substantial potato yield loss. This information will assist potato growers in the Columbia Basin prevent potato yield loss due to the beet leafhopper by controlling this insect pest when its number reaches two leafhoppers per potato plant.
Technical Abstract: Potato purple top disease is caused by a phytoplasma known as Beet Leafhopper Transmitted Virescence Agent (BLTVA), which is vectored by the beet leafhopper (BLH, Circulifer tenellus Baker). Previous studies determined that BLTVA causes significant reduction in yield and tuber quality; however, determining the economic threshold for this insect pest has been challenging. In 2009-2011, potato plants at different growth stages were exposed to varying densities of BLH in a screen house located at the Hermiston Agricultural Research and Extension Center in Hermiston, OR. The densities of BLH were one BLH per plant (low), two BLH per plant (medium), and five BLH per plant (high). Releases occurred at the following growth stages: vegetative, tuber initiation, tuber bulking, and maturation. The treatments were arranged in a randomized complete block design with three replications per treatment. Disease incidence was monitored weekly and yield was assessed. When all three years were combined, we found that increasing rates of disease incidence correlated with decreasing yields. We also found that decreasing yields correlated with later BLH release times. There was a mean decrease in yield of 0 - 12% at a density of one BLH per plant, 6 - 19% at two BLH per plant, and 6 - 20% for five BLH per plant. This data suggests an economic threshold of one or two BLH per plant for the Columbia Basin.