Submitted to: International Journal of Fruit Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/15/2010
Publication Date: 5/7/2010
Citation: Zasada, I.A., Pinkerton, J., Forge, T. 2010. Occurrence and distribution of plant-parasitic nematodes in Pacific Northwest blueberry production systems . International Journal of Fruit Science. 10:123-133. Interpretive Summary: Plant-parasitic nematodes are microscopic soil worms that cause ten billion dollars in U.S. crop losses annually. Blueberry is a rapidly expanding agricultural sector in the Pacific Northwest regions of the United States and Canada. This research was conducted to determine the occurrence and distribution of plant-parasitic nematodes in blueberry fields in the Pacific Northwest and Canada, which were unknown prior to this research. Soil samples were collected from 234 blueberry fields and nematodes extracted, identified, and quantified. Plant-parasitic nematodes were commonly encountered in blueberry fields in the Pacific Northwest. However, the distribution of specific types of plant-parasitic nematodes varied between locations in the Pacific Northwest. These results are significant because they will help guide plant-parasitic nematode research efforts by scientists to better serve blueberry growers in the Pacific Northwest regions of the United States and Canada.
Technical Abstract: Blueberries (Vaccinium spp.) are an important agricultural crop in the Pacific Northwest (PNW) of the United States and coastal British Columbia (BC) of Canada. Relatively little is known about the occurrence, distribution, and damage potential of plant-parasitic nematodes in this geographical location. Three separate surveys were conducted to elucidate the occurrence and distribution of plant-parasitic nematodes in the PNW and BC. Soil samples were collected from a total of 234 blueberry fields and nematodes were extracted, identified to genus, and quantified. Plant-parasitic nematodes were detected in 73% of the surveyed blueberry fields. The two most commonly encountered plant-parasitic nematodes in all geographical locations surveyed were Paratrichodorus spp. and Pratylenchus spp., which were detected in 27% and 53% of the fields, respectively. In fields where Paratrichodorus spp. and Pratylenchus spp. were detected population densities ranged from 1 to 1,820 and 1 to 423 nematodes/250 g of soil, respectively. Xiphinema americanum was also detected during the surveys, but was geographically limited to southern Washington and the Willamette Valley of western Oregon where it was detected in 75% and 21% of the fields, respectively, at population densities ranging from 0 to 103 nematodes/250 g soil. Five other plant-parasitic nematode genera/families were detected during the surveys but never at a frequency of detection greater than 23%. Economic damage thresholds have not been developed for plant-parasitic nematodes on blueberry, therefore it is difficult to relate the population densities observed in these surveys to potential damage to the plant.