In the Pacific Northwest (PNW), the two most common root-knot nematodes are Meloidogyne hapla and Meloidogyne chitwoodi. These nematodes can infect a wide variety of crops and can cause significant losses. Currently, it is common for the field of nematology to use labor-intensive microscopy to identify plant-parasitic nematodes based on...
Late blight, caused by Phytophthora infestans, is a devastating problem to potato production in many parts of the world. While the foliar phases of this disease are well characterized, tuber infection, leading to quality losses and disease perpetuation, is less well understood. Experiments were conducted during 1998 and 1999 in...
Most studies of plant disease epidemiology have focused on epidemics in host
populations composed of a single genotype. But crop plant diversity can be a useful
means of improving the deployment of resistance genes. In a series of experiments with wheat stripe rust and potato late blight, we studied factors...
Population size of Clavibacter michiganensis subsp.
sepedonicus in potato cv Russet Burbank and plant response
as affected by drought were assessed in a greenhouse
experiment. Water deficit stress and no stress treatments,
and inoculum densities of 0 or 2 X 10⁷ cfu C. m.
sepedonicus/seed piece were arranged factorially. Stem...
A potato plant growth and production model is developed with
the objectives of analyzing management alternatives and exploring
the nature of the early dying syndrome. The geographic area of
focus was the centerpivot irrigated circles of Oregon's Columbia
Basin. A problem analysis of the potato production system of this
area,...
Field plots of cv. Russet Burbank potatoes from a
single seedlot were established at four sites over two
seasons (1985-86) in two locations in Oregon to determine
the role of water-borne inoculum of Erwinia carotovora in
plant infection. One site at each location was irrigated
from a surface-water source and...
A greenhouse experiment was conducted in 1991 and in
1992 to determine the effect of soil water pressure on
potato (cv Russet Burbank) plant growth and infection by
Verticillium dahliae. Soil water pressures of -0.01,
-0.03, -0.08, or -0.15 MPa were combined factorially with
two inoculum concentrations, 0 or 10...
Potato Virus Y (PVY) is an enduring problem for potato production worldwide. Potato varieties that resist the “ordinary” strain PVYO were developed by breeders, but in recent years, recombinant strains of PVY have been able to circumvent this strain-specific resistance and evade growers and seed certification officials by causing fewer...
Bacterial soft rot of potato (Solanum tuberosum), caused by Pectobacterium and Dickeya species, is among the most common and destructive potato diseases in the United States. These pathogens cause a variety of vascular wilts, and in potato cause a disease complex that includes tuber soft rot, blackleg, aerial stem rot,...
Field trials were conducted during 2001 to 2003 to investigate soil population dynamics of Meloidogyne chitwoodi, tuber symptom suppression using oxamyl, and post-harvest tuber symptom development on short-season potato varieties Russet Norkotah and Russet Nugget (San Luis Valley only). The experiments were located in the San Luis Valley in Colorado,...