Crop Profile for Hazelnuts in Oregon

Prepared: July 14, 1999
Revised: September 2, 1999

General Production Information


Production Regions

Oregon's Willamette Valley farmers have grown hazelnuts since 1858 when the nuts were called filberts, a term still used by many Oregonians. Counties in order of production are Yamhill, Washington, Marion, Clackamas, Lane, Polk, Linn, and Benton. Yamhill County produces 9,930 tons or 21.6% of the state’s total (3).



Cultural Practices

Hazelnut crop size can differ greatly from year to year. Several factors caused smaller crops: trees are recovering from record crops the previous year; winter ice storms caused severe wood damage; and cool, wet spring weather resulted in a light flower bloom that hindered pollen movement (7).

Hazelnuts are best adapted to western Oregon and Washington. Because they blossom in late January or February, frost damage is a problem in colder areas. Hazelnuts reach bearing age in 4 years and have a life expectancy of over 50 years. Trees do best in deep, well-drained soil. They seldom need irrigation but do require 800–1200 hours of temperatures below 45 ° F to produce nuts. From September through November, harvesters gather and dry the nuts that have fallen to the ground (6,8).



Insect Pests

In the southern Willamette Valley, insects in hazelnuts (in order of importance) are moths, leafrollers, and mites. In the central Valley, the filbert bud mite is the most important insect. Of minor importance are loopers, mealybugs, aphids, weevils, scales, and caterpillars (5,6,9).

Chemical controls:
Growers most commonly apply the organophosphate, chlorpyrifos (Lorsban), for leafroller control (10).

Other insecticides used on hazelnuts are azinphos-methyl (Guthion), endosulfan (Thiodan), and esfenvalerate (Asana) (11).

For more details on insect control in Oregon hazelnuts, see the 1999 PNW Insect Control Handbook, pages 163–166. (Go to for ordering information.)

Black lights, pheromone traps, and mating disruption are non-chemical means of insect control (6).

Cultural controls:
Worm infested nuts are flailed the first of September (6).

Biological controls:
In recent years, researchers have introduced the use of biocontrol for mites and a parasitoid wasp that controls filbert aphids (6,10).




Hazelnuts suffer from a variety of diseases with number one being Eastern filbert blight (EFB), second molds, and third other blights. Powdery mildew, stunt, and blasts can also infect trees. Eastern filbert blight (EFB) has the potential to decimate the industry. Discovered in the Willamette Valley in 1974, the disease is slowly spreading south (6,14).

Chemical controls:
Orchardists use many copper-based products. They apply Bordeaux, copper hydroxide, and chlorothalonil (Bravo) in mid-March at budbreak to control EFB (15).

For more details on disease control in Oregon hazelnuts, see An Online Guide to Plant Disease Control, (16).

Cultural controls:
Oregon State University researchers are working to develop an eastern filbert blight resistant or immune hazelnut variety. Varieties ‘Willamette,’ ‘Lewis,’ and ‘Clark’ show improved resistance but not immunity (5,14).

Studies suggest that it will be possible to use partially resistant parents to breed hazelnuts that will exhibit fewer and smaller cankers (17).

Researchers have identified the single, dominant gene that gives hazelnuts resistance to EFB. Their goal is to have a good-yielding, immune variety by 2004 (18).

Farmers can control EFB to a point with pruning techniques, but all infected trees eventually die. Workers scout orchards to remove and destroy all infected wood prior to budbreak (19).

Biological controls:
Slugs, some insects, and some types of fungi and bacteria eat EFB spores. For the biological measures to be significant; however, controls must achieve 99% effectiveness, and that has not happened yet (13).




Nematodes are not a problem in Oregon (20).




Weed control in hazelnut orchards depends on whether growers attempt control as part of site preparation or in conjunction with a new or established planting (12).

Chemical controls:
Farmers apply herbicides in new and established orchards, but the usage is mainly in herbicide strips, with not a lot of chemical being used (6).

Nut growers use paraquat (Gramoxone), 2,4-D, and glufosinate-ammonium (Ignite) for green sucker control (12).

Other herbicides used for broadcast treatment of weeds, including wild garlic, are glyphosate (Roundup), norflurazon (Solicam), and simazine (Princep) (11).

For more details on weed control in Oregon hazelnuts, see Weed & Vegetation Exchange for Orchards at (13).

Flailing is the most prominent weed control method in new and established hazelnut orchards. Growers also are using more cover crops for weed control (6).

Cultural controls:
Many orchardists use mowing as a means of weed control (6).




Jeff Olsen
Yamhill-Polk-Marion Country Extension
2050 Lafayette Street
McMinnville, OR 97128-9333

Polly Owens
Oregon Hazelnut Commission and Marketing Board
21595 A Delores Way NE
Aurora, OR 97002

Ross Penhallegon
Lane Country Extension
950 W 13th Avenue
Eugene, OR 97402-3999

Jay Pscheidt
Botany and Plant Pathology
Oregon State University
Corvallis, OR 97331




1. Crop Profile for Commodity in State. instructions.html (accessed Feb 1998).

2. 1997 Oregon County and State Agricultural Estimates; Special Report 790; Oregon State University Extension Service: Corvallis, OR, revised July 1998.

3. Commodity Data Sheet, Hazelnuts; 5150-97; Oregon State University Extension Service: Corvallis, OR, March 1998.

4. Hazelnut Facts. (accessed Nov 1998).

5. Olsen, J. Yamhill-Polk-Marion County Extension, McMinnville, OR. Personal communication, May 17, 1999.

6. Penhallegon, R. Lane County Extension, Eugene, OR. Personal communication, June 8, 1999.

7. Crop Report, Hazelnut forecast down 65 percent. oass/hazel898.htm (accessed Nov 1998).

8. Stebbins, R.L.; Walheim, L. Western Fruit, Berries & Nuts; HP Books, Inc.: Tucson, AZ, 1981.

9. Pacific Northwest Insect Control Handbook; Extension Services of Oregon State University, Washington State University, and the University of Idaho: Corvallis, OR, 1998.

10. Gianessi, L.P. The Uses and Benefits of Organophosphate and Carbamate Insecticides in U.S. Crop Production, 1997. (accessed June 1998), National Center for Food and Agricultural Policy, Washington, D.C.

11. Rinehold, J.; Jenkins, J.J. Oregon Pesticide Use Estimates for Small Fruits (1995) and Tree Fruits (1996); EM 8673; Oregon State University Extension Service: Corvallis, OR, January 1998.

12. Pacific Northwest Weed Control Handbook; Extension Services of Oregon State University, Washington State University, and the University of Idaho: Corvallis, OR, 1998.

13. Weed & Vegetation Exchange for Orchards, OSU, WSU, & UI Extensions Cooperating. (accessed July 1999).

14. Rost, B. The nutty professors. Oregon's Agricultural Progress 1998, Winter/Fall, 45 (1/2), 20-25.

15. Hazelnut 1998 Pest Management Guide for the Willamette Valley; EM 8328; Oregon State University Extension Service: Corvallis, OR, revised March 1998.

16. An Online Guide To Plant Disease Control, Oregon State University. (accessed July, 1999).

17. Osterbauer, N.K.; Johnson, K.B.; Mehlenbacher, S.A.; Sawyer, T.L. Analysis of resistance to eastern filbert blight in Corylus avellana. Plant Disease 1997, 81(4), 388-394.

18. Gene to help U.S. hazelnut growers fight blight. news/Fruitandnut/filbli.html (accessed Feb 1999), News & Features, Oregon State University Extension & Experiment Station Communications: Corvallis, OR, July 3, 1997.

19. Hazelnut 1998 Pest Management Guide for the Willamette Valley, revised March 1998. (accessed Feb 1999), revised for the Internet July 1998.

20. Pacific Northwest Plant Disease Control Handbook; Extension Services of Oregon State University, Washington State University, and the University of Idaho: Corvallis, OR, 1998.

This crop profile was prepared by P. Thomson, W. Parrott, and J. Jenkins, Agricultural Chemistry Extension, Department of Environmental and Molecular Toxicology, Oregon State University. The information was reviewed by J. Olsen, Yamhill-Polk-Marion County Extension; R. Penhallegon, Lane County Extension; and P. Owens, Oregon Hazelnut Commission.


Database and web development by the NSF Center for Integrated Pest Managment located at North Carolina State University. All materials may be used freely with credit to the USDA.