2017 ASHS Annual Conference

Cover crops can provide many benefits to agroecosystems, such as lessening soil erosion and increasing water infiltration. However, cover crop use is not common in established red raspberry (Rubus idaeus) production fields in the Pacific Northwest. Growers are concerned about resource competition between the cover crop and raspberry crop as well as increasing population densities of the plant-parasitic nematode, Pratylenchus penetrans, which has a wide host range and has been shown to reduce raspberry plant vigor, yield, and economic returns. A two-year study was conducted in a 4-year-old ‘Meeker’ red raspberry field in northwest Washington to evaluate the effects of nine alleyway cover crops and the industry standard bare cultivated soil on P. penetrans population dynamics in this production system. Impacts on raspberry estimated yield and fruit quality were also measured. There were no significant differences in raspberry yield or fruit quality among treatments in either year of the experiment. Alleyway P. penetrans populations did not affect population densities of P. penetrans in corresponding raspberry beds. Pratylenchus penetrans population densities did not increase over time in raspberry roots adjacent to cover crops compared to those adjacent to bare soil alleyways. In the field, all of the cover crops were hosts for P. penetrans, but differed in their suitability; none were as good of hosts as raspberry. Raspberry grown in cultivated, bare soil plots did not fare better over time than raspberry grown in cover crop plots under any measured parameter. To further evaluate the host status of the cover crops for P. penetrans, two greenhouse host assays were conducted. Two mustards commonly used as cover crops in the Pacific Northwest, ‘Pacific Gold’ and ‘Ida Gold’, were also evaluated; ‘Meeker’ raspberry was used as the positive control. In both host assays, ‘Norwest 553’ wheat and a perennial ryegrass mix were consistently poor hosts for P. penetrans while ‘Nora’ oat, ‘TAM 606’ oat, and both mustards were good hosts for P. penetrans. Implementation of alleyway cover crops may improve soil quality, but growers should select a cover crop appropriate for their production system.