By improving the health of its potato plants, Gies Farms was able to achieve higher yield and lower input costs. This Moses Lake, Wash., family operation accomplished this feat by applying Employ, a second-generation harpin product.
"Because of better overall plant health, the Employ-treated field produced 10 tons more potatoes and had almost another ton's worth of fewer inputs," explains Joe Gies. "For example, we had one less Tanos application for slime and one less Omega application for white mold. Saving $53/acre for the total cost of both fungicides is like growing an extra 3/4 of a ton of potatoes per acre."
Employ is a combination of the active domains of four different bacteria-derived proteins that triggers hypersensitive responses in crops and creates a natural defense against diseases and pathogens. They also enhance the plant's immune system, increase plant growth, reduce nematode fecundity and increase yield.
Gies Farms tried Employ for the first time in 2012. They used wipers, two half-pivots, for their treated and untreated tests. The untreated field was planted April 17, and the treated field April 20; both fields were planted in 34-inch rows. The untreated and treated fields were Royal, very-fine sandy loam, and Timmerman, coarse sandy loam, respectively.
Two ounces of Employ per acre were applied via chemigation on July 3, and a second application was made Aug. 6.
"Chemigation provides a higher response than conventional applications," Gies says. "My father, Dale Gies, has worked closely with chemigation since its infancy and has proved that it enhances a product's efficacy. There's no better way to treat your fields than with chemigation. It's an easy, exact, low-cost method to apply products like Employ."
The recommended application and timing of Employ for market potatoes is two ounces at tuber set and two ounces applied 21 days later.
"We were probably a week or two late on the first Employ application" Gies says. "However, we saw some tremendous results. Beginning about two weeks after the first Employ application, the treated field looked better than the untreated field for the remainder of the season. It made for a really good-looking potato field that was actually enjoyable to walk through. The potatoes' size and uniformity in shape were better in the Employ-treated field."
Yield and Quality
Harpins have been tested extensively in potatoes for the past 10 years and have demonstrated an average yield increase of 8 percent. Larger tubers and increased gross yield occurred in Gies' treated crop. "On our Alturas, an indeterminate variety, we generally try to set 14 to 18 tubers per plant," he says. "The plants averaged 18 potatoes in both fields, but the potatoes in the Employ-treated field were 15 to 20 percent bigger. We went from 29 tons on the non-treated field to 38-plus tons on the treated field."
Gies harvested the untreated field from Sept. 29 to Oct. 2, and the treated field Oct. 2-7. The treated field averaged 9.3 tons more per acre-a 31 percent yield increase-than the untreated field.
Harpins are bacteria-derived proteins that trigger the hypersensitive response and create a natural defense against diseases and pathogens. By helping plants defend against disease, they complement a fungicide program.
"White mold and slime are our two biggest yield-limiting factors," Gies says. "We have tried controlling these diseases solely with fungicides, and this past year we also tried to control them by limiting moisture, which was tough to manage with wipers because you get a lot of water at the ends when the pivot passes twice.
"We were able to keep the untreated field drier than the treated field, but it still had the most white mold pressure. We had very little white mold in the Employ-treated field, which definitely had more moisture."
Gies says the No. 1 reason why growers should try Employ is improved overall plant health. "No matter what we were dealing with-white mold, moisture stress or whatever-the Employ-treated field had healthier plants," he says.
"Employ gave us a healthier crop and made us money. I'm absolutely looking forward to using it again this year, and we'll have more potato acres. Additionally, Employ works extremely well with our bio-fumigant mustard, which helps suppress weeds, fungal pathogens and insects; we have used green manures for about 20 years. Employ is another useful tool in our IPM program.
"Last year, we used wipers for the treated and untreated test. This year we will do a full 140-acre pivot and split it side by side on the exact same field so we'll have an even better comparison. However, I almost don't want to split the circle because that means I'll leave 70 acres untreated. I would rather treat every acre because Employ really benefits the crop."
Reduces Storage Loss
Gies' Alturas went to a dehydration plant, and were not graded; they were sold field run. However, Employ also contributes to post-harvest quality storage. Plant Health Care, Inc., which manufactures Employ, has conducted extensive post-harvest studies that demonstrate the product actually slows the respiration rate of the potatoes and reduces the amount of disease in potatoes that are put into storage.
For example, widespread research was conducted at 13 sites in Washington and Idaho on the pre-harvest application effects on post-harvest storage. At each site, trials included three treatments: Employ, Myconate and both Employ and Myconate. Additionally, an untreated check was left for comparison. Samples were pulled from the harvested crop and placed inside growers' storage buildings for about seven months.
Overall storage loss was slight. All three treatments resulted in less storage loss than the untreated potatoes. Two causes of loss were identified: normal respiration, and more rarely, rot due to pathogens such as Pythium. Employ helped with both situations, but made a bigger difference when rot occurred.
Employ alone had the largest effect on storage loss, reducing it from about 4.6 percent in the untreated to about 1.9 percent in the Employ-treated tubers, which is a 58 percent reduction in loss.
In 2011, Sym-Agro, Inc. entered into an agreement with Plant Health Care, Inc. (the U.S.-subsidiary of PHC, plc) to distribute harpin products in the Western United States under the trade names Employ, ProAct and Pretect. Sym-Agro, Inc. is PHC's master distributor in the region and provides technical and marketing support in those regions. For more information, go to www.sym-agro.com. PG