Do You Want Nematodes with Your Fries?

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Nematode-Damaged Potato

Farmers in Oregon and Washington grow 12 billion pounds of potatoes every year. 90% of this production is for processing into potato chips and fries. 80-90% of the potato acres in Oregon and Washington are fumigated every year to reduce populations of nematodes which are microscopic parasitic worm-like animals that live in the soil and penetrate potatoes underground. Females feed just under the potato skin and deposit 200 to 1000 eggs. Brown spots become evident when the eggs are laid. Growers fumigate the soil to reduce the nematode populations because of the potential for rejection of the potatoes for processing into consumer products.

Columbia root-knot nematode (CRN) infects and develops in potato tubers but does not cause yield loss. Columbia root-knot nematode causes quality defects such as galling on the surface and small brown spots surrounding adult females when peeled. The external and internal defects render tubers unacceptable for fresh market sales and internal defects are unacceptable for processing. For processed potatoes, if between 5% and 15% of the tubers in a field have visual defects the whole-field crop can be substantially devalued or rejected. Based on USDA 2010 yields and prices, the average gross value of potatoes in Idaho was $6,921/ha. The rejection of a potato crop grown on an average 52.6-ha center-pivot-sprinkler-irrigated field represents a loss of $364,000. The potential for dire financial consequences from the presence of CRN in potato tubers is taken very seriously by producers.

Because potential for crop rejection exists with low population levels at planting, fields with any CRN must be treated with a preplant fumigant, nonfumigant nematicides, or both.”

Authors: King, B. A., and J. P. Taberna, Jr.
Affiliation: USDA, Agricultural Research Service, Kimberly, ID
Title: Site-Specific Management of Meloidogyne chitwoodi in Idaho Potatoes Using 1,3-Dichloropropene; Approach, Experiences, and Economics
Source: Journal of Nematology. 2013. 45[3]:202-213.

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No Apple Maggots in Northwest Orchards Thanks to Spraying Outside the Orchards

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Apple Maggots

Apple maggot is a native pest of the eastern United States and Canada. In 1979 it was discovered in Oregon and has since moved into California, Washington, and other Western states. Female apple maggot adults deposit eggs singly under the apple skin. Damage is caused when larvae burrow and feed on apple flesh. Browning of the trails occurs as the apple responds to this injury and bacteria associated with maggots cause fruits to rot internally. No Western commercial apples have been infested with maggots thanks to spraying trees outside the orchards to keep them away.

“The first detection of this species [apple maggot] infesting apples in western North America occurred in the United States in Oregon in 1979; flies were caught in neighboring Washington the following year. However, no commercial apples from central Washington, the major apple growing region in the United States, have been found to be infested by R. pomonella, even though adults were first detected within this region in 1995.  

In Washington, an R. pomonella quarantine is established in 22 counties, including two under partial quarantine.

R. pomonella is widespread and abundant in Washington west of the Cascade Mountain range, but is much less abundant in central and eastern Washington except in Spokane County. It occurs in low numbers on the margins of the apple-growing regions in central Washington in native hawthorns and in even lower numbers in unmanaged roadside and backyard apples.

…In the major apple-producing regions of the Pacific Northwest of the United States, control does not occur at the orchard level but rather outside orchards. There is zero tolerance for infested apples. The probability of R. pomonella being moved in apples from Washington to Canada or Mexico is minimized by an extensive annual fly detection and insecticide spray response program conducted by the WSDA and cooperating county pest control boards. …Similar programs exist in Oregon, Idaho, and California.”

Authors: Yee, W. L., et al.
Affiliation: Agricultural Research Service, United States Department of Agriculture
Title: Status of Rhagoletis (Diptera: Tephritidae) Pests in the NAPPO Countries.
Source: J. Econ. Entomol. 2014. 107[1]:11-28.

Fungicides Prevent Wheat Losses in the Pacific Northwest – Organic Growers Can Only Pray

Cool, wet weather causes explosions of the stripe rust fungus in wheat fields of the Pacific Northwest. Two articles by Matthew Weaver explain how most growers applied fungicides to prevent yield loss in 2011 while organic growers could only hope that they would not be hit by the disease.

From “Researchers say vigilance against stripe rust a must”:

“Even though there’s more stripe rust in Pacific Northwest wheat fields this year, researchers say the outlook is good -— as long as farmers spray their fields and keep an eye on them.”

“…most growers in Oregon are already on their second application of fungicide and many will make a third application, which is extremely unusual.”

“In most fields, the stripe rust is under control if sprayed. Very few fields haven’t been sprayed, Chen said. Farmers who haven’t should compare the cost of spraying to the potential for yield losses if they don’t, Chen [research plant pathologist with USDA’s ARS] said. ‘It can not only cause a problem in their fields, but also to their neighbors and potentially to the whole region,’ he said, noting rust spores can be carried by the wind.”

From “Rust resistance key to organic wheat survival”:

“Organic wheat growers in the Pacific Northwest are concerned about stripe rust, an epidemic for which they have few treatment options. … Oregon State University wheat breader Mike Flowers said most organic growers were hit by the stripe rust ‘pretty hard’ but losses vary depending on the variety of wheat they grew. … Corvallis, Ore., farmer Clinton Lindsey, farm manager of A2R Farms, said one of his best red wheat fields was ‘completely devastated’ by the rust.”

“There aren’t many options available to organic producers, researchers and farmers say. ‘Pray or not pray,’ said Owen Jorgensen, a Coulee City, Wash., farmer who is on the northern edge of the stripe rust region.” 

Author: Matthew Weaver
Titles:”Researchers say vigilance against stripe rust a must” 27 May, 2011 and “Rust resistance key to organic wheat survival” 8 July, 2011
Publication: Capitol Press