|Rondon, Silvia -|
|Hamm, Philip -|
Submitted to: American Journal of Potato Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 13, 2011
Publication Date: March 5, 2012
Citation: Crosslin, J., Rondon, S., Hamm, P. 2012. Population dynamics of the beet leafhopper in northeastern Oregon and incidence of the Columbia Basin potato purple top phytoplasma.. American Journal of Potato Research. 89:82-88. Interpretive Summary: The potato purple top disease is caused by infection with a type of bacterium called phytoplasma. This phytoplasma is transmitted to potatoes and other vegetable crops by the beet leafhopper. This insect is widespread in the Columbia Basin region of Washington and Oregon, but a detailed examination of the population dynamics of the leafhopper and the incidence of the phytoplasma in the insects was lacking. Here, we report the results of a three year study on the dynamics of beet leafhopper populations and the incidence of the phytoplasma in insects collected at a number of locations in northeastern Oregon. Generally the population peaked in June through early July. The incidence of phytoplasma in the insects was somewhat variable, but was often around 20%. Insects carrying the phytoplasma were present throughout the growing season. These results indicate that measures to control this insect are necessary in order to reduce the incidence of disease in potatoes and other vegetable crops in this region.
Technical Abstract: Beet leafhoppers were collected weekly on yellow sticky traps placed at 35 locations in Morrow and Umatilla Counties in northeastern Oregon in April through November 2007, 2008, and 2009. Insects were counted, collected, and a subset of the insects was tested for the presence of the beet leafhopper transmitted virescence phytoplasma, the causal agent of potato purple top disease in this region. Beet leafhoppers were present throughout the sampling period and the number of insects collected peaked in June of each year with smaller peaks in July and October. Of the insects tested for phytoplasma in 2007, 2008, and 2009, 20.8, 18.2, and 22.4% tested positive for phytoplasma, respectively. Most of the phytoplasma-positive insects were collected from mid-June through July. Positive insects, however, were collected as late as November 13 in 2007 and 2008. These data indicate that the potential for development of purple top disease of potatoes from migrating beet leafhoppers in this important potato producing region is quite high and measures to control this pest throughout the growing season are probably necessary in order to reduce disease pressure.