Researchers on alert for new potato pathogen

AFP Correspondent

PAINTER, Va. (Aug. 18, 2015) — A perfect summer day greeted the 50-some attendees at the Research Field Day at the Eastern Shore Agricultural Research and Extension Center.
Participants toured research sites as scientists, Virginia Cooperative Extension agents and specialists briefly shared their work on crop varieties, crop diseases, chemicals and cultural practices.
Dr. Steve Rideout, associate professor of plant pathology and director of ESAREC, discussed a new potato pathogen that “may or may not” have reached the shore.
The pathogen, colloquially known as “blackleg on steroids,” originated in Maine. Rideout reported the research center is working with scientists at the University of Maine to determine what seed lots and cultivars may be affected.
Rideout reported that full-season soybeans “look fantastic.” He said a fungicide applied between the R3 and R5 growth stages “may pay off this year.”
Postdoctoral associate Dr. Ganyu Gu discussed an ongoing project done in connection with the Food and Drug Administration to examine the effect of salmonella-contaminated irrigation water on fruits and vegetables.
He described laboratory experiments on the efficacy of commercial sanitizer products on irrigation water.
Researchers also are studying salmonella and listeria in cucumbers.
They inoculate store-bought cucumbers with the pathogens and study the remaining incidence of the pathogen after periods of time.
Dr. Laura Strawn, assistant professor of food science discussed the Food Safety Modernization Act and the importance of good water quality on the farm and in packing houses.
Her team is testing water from packing houses and will establish a water quality profile for growers so they meet FSMA standards. She reported that E. coli. and salmonella levels are “pretty much” within FSMA standards but salmonella sporadically exceeds the standard.
Research will determine the fate of E. coli. in cantaloupes irrigated with contaminated water. Using cow manure, Dr. Strawn’s team will determine how much E. coli remains after varying periods of time.
Dr. Ramón Arancibia, assistant professor of horticulture and Extension specialist, described his work with vegetable crop row covers.
He explained that covers are common in the spring, but he is studying whether they can be used in summer or fall.
He explained row covers serve as a physical barrier to insects, provide better conditions for growth and reduce stress by enabling the plant to survive with less water. He found row covers double the yield of cucumbers in some cases.
He is testing three thicknesses of plastic – 0.5, 1.0 and 1.5 ounces per square yard; he said the two thicker sheets can be reused.
Currently, he is working to determine the optimal time to remove the covers.
Trials are being done in summer and fall to discover differences in disease incidence.
Dr. Arancibia also presented his variety trials on eggplants and peppers to study the difference between black and white ground-cover plastic.
He discussed work on a new sweet potato variety, including determining the cost of production.
He said farmers on Virginia’s Eastern Shore grow fresh market sweet potatoes on small farms up to about 30 acres. He reported researchers in other parts of the country have been very successful in increasing yield and quality. He said he hopes for similar results.
Dr. Thomas Kuhar, professor of entomology, discussed fall army worm in late-planted sweet corn and plans to test a new insecticide.
He said it is difficult to control the worm because it is down inside the whorl.
Dr. Kurt Vollmer, postdoctoral assistant, described his work on the impact of Atrazine combination for no-till corn at various rates of application. He reported good broadleaf weed control, but less successful results with grasses.
Dr. Charlie Cahoon, assistant professor and weed Extension specialist, who is new to ESAREC, explained his work on weed control following wheat harvest.
He demonstrated the results of work with varying application timing, choice of herbicide and application rate.
He introduced participants to Palmer amaranth, an aggressive, fast-growing weed that has become a serious problem in vegetable and row crops in the South and is “just starting to reach Virginia,” he said.
He reported the plant is very prolific and hard to control when more than four inches high. Cahoon explained the weed has separate male and female plants which should be torn up and disposed of anytime they are discovered.
He said Arkansas and Tennessee have PPO-resistant Palmer amaranth. If such a tolerance develops in the weed in Virginia, “the only herbicide to use is Liberty and it won’t be long before we have Liberty-resistant weeds.”
He reported that seed for soybean varieties with tolerance to several herbicides is now available; Enlist and Extend soybeans are 2-4D- and dicamba-tolerant.
Mark Reiter, associate professor and Extension specialist in crop and soil environmental sciences, and Jenny Templeton, NRCS soil conservationist, led a walking tour of their cover crop research plots.
The project, funded by an NRCS conservation innovation grant, examines options for cover crops and seeks to demonstrate what each looks like, how it performs and how the crop planted after the cover crop performs.
Variations in mixes of cover crops, seeding rates and planting dates are being studied. On this day, the plots seemed to show corn planted after hairy vetch was the most successful. Final results are well in the future as the experiment will run for three years and involve four replication plots for each protocol.
Reiter explained the goal of the first year is to examine the effect on low-organic matter soil.
The second year will look at a single fertilizer regime — 150 pounds of nitrogen. The third will study different nitrogen rates.
Dr. Richard Snyder, director of the Eastern Shore Laboratory of the Virginia Institute of Marine Science, said he is pleased with cover crops that keep nutrients on the land.
He said aquaculture is highly dependent on soil quality.
ESAREC hosts field days twice a year at its 226 acre office and research site.
The events are free and open to the public.