Location: Horticultural Crops ResearchTitle: Distribution and longevity of Pratylenchus penetrans in the red raspberry production system
Submitted to: Journal of Nematology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/13/2016
Publication Date: 12/16/2016
Citation: Kroese, D.R., Weiland, G.E., Zasada, I.A. 2016. Distribution and longevity of Pratylenchus penetrans in the red raspberry production system. Journal of Nematology. 48(4):241–247.
Interpretive Summary: Root lesion nematodes are microscopic soil worms that attack raspberry plants and cause significant loss in yield to this crop. Raspberry farmers face an enormous problem because they lack effective ways of reducing the numbers of root lesion nematodes when planting a new crop. This research was conducted to determine where nematodes are surviving in roots and soil between plantings of raspberry. Results indicate that root lesion nematodes can survive in dead raspberry roots for up to 8 months after a previous raspberry planting is removed. In addition, root lesion nematodes are also surviving in soil even after the application of management practices to reduce their numbers. These findings will help guide growers in ways to improve current management practices targeting root lesion nematodes.
Technical Abstract: One of the major production constraints on the production of red raspberries in the Pacific Northwest is the presence of the root lesion nematode Pratylenchus penetrans. Current management of this nematode relies heavily on pre-plant soil fumigation, however regulations have made the practice more difficult and expensive. Additional issues with soil fumigation include lack of efficacy at deeper soil depths and potential inability to penetrate raspberry root material remaining in the field during fumigation that may harbor P. penetrans. To address these issues, two field experiments were conducted in northern Washington. In the first experiment, the residency time of P. penetrans in root material from the previous raspberry crop, which was terminated with or without the use of herbicides, was monitored over time. Pratylenchus penetrans was found in root material from 6 to 8 months after the crop was terminated, and herbicide application did not reduce P. penetrans residency time compared to untreated root material. In a second experiment conducted at two fields, the vertical distribution of P. penetrans at three different times during the field establishment process (pre- and post-fumigation, and at planting) was determined. Both locations had detectable pre-fumigation P. penetrans populations at all depths. However, post-fumigation the vertical distribution of P. penetrans differed between locations. Pratylenchus penetrans was found at shallower depths of 16 to 30 cm (maximum population densities of 44 P. penetrans/100 g soil) in the field with coarser soil while in the other field with a finer soil type nematodes were found at deeper depths of 76 to 90 cm (maximum population densities of 8 P. penetrans/100 g soil). At planting, the vertical distribution of P. penetrans tended to equilibrate among depths at both fields, but the overall distribution across depths at each field was similar to that observed post-fumigation.