Wheat Seed
Triticum aestivum (Gramineae)
Fast Facts:
Acres in Washington: 1,789,297 soft white
1,789 hard white winter
3,500 hard white winter
242,700 hard red winter
Number of Growers: 3,500
Description
of crop:
Washington wheat farmers grow 6 classes of wheat: two types of soft white, hard red
winter, hard red spring, hard white and durum. Winter wheat is planted in the fall and
harvested the following summer. Spring wheat is planted in the spring and harvested in
mid-summer to early fall. Most of the wheat produced in the state is in 15 central and
eastern Washington counties. Wheat seed and wheat for food and feed are produced in
with wheat seed. Since wheat is a self-pollinating
crop and the grain can be used as seed, farmers tend to replant their own seed. Seed
production follows a generation system to ensure that all seed that is marketed to farmers
originates from a known source (breeder seed). Certified seed is the progeny of breeder
seed and is usually produced under the supervision of a breeder or his/her designated
agency and under the control of a seed quality control agency. 85% of wheat acreage is
planted with certified seed.Washington is the largest users of certified seed in the U.S.
Wheat seed should never immediately follow wheat, unless the wheat crop in the
previous season was of the same variety. A good crop rotation helps in pure seed
production. Wheat should not follow other cereals (barley, oat, rye and triticale) and other
forage crops. Legumes, vegetables or clean fallow can be followed by wheat seed. The
optimum seed rates for wheat vary with variety, location, and method of planting.
Mechanical harvesting is used for seed production fields. The most critical factors to
consider are seed moisture content, mechanical damage and cleanliness of equipment.
For seed crops, dry weather during ripening and harvesting is essential. After wheat seed
has been harvested, the seed, if necessary has to be dried and cleaned. This involves the
removal of inert matter, the seeds of weeds and other crops and seeds that are damaged or
diseased. Seed needs to be dried before it goes into storage and once in storage needs to
be protected from moisture by being kept at cool temperatures, with low relative
humidity. Seed can then be stored in favorable conditions that can protect it from damage
and pests until it can be planted.
Key pests:
Weeds are a key pest in wheat seed production. These include lambs quarter, mayweed
chamomile, Italian ryegrass, wild oats, pigweeds, downy brome and pricky lettuce.
Diseases that affect wheat seed are black point, cephalosporium stripe, wheat seed decay
and damping off and wheat streak mosaic. Insect pests in wheat include the Hessian fly,
Russian wheat aphid, the bird cherry-oat aphid, the English grain aphid, the rose grass
aphid, the brown wheat mite, the cereal leaf beetle, the leaf curl mite, the wheat head
armyworm, grasshoppers, leaf miners, and wireworms. Nematodes can also be a
problem, and include the cereal cyst, the cereal root-knotand the root lesion nematodes.
Key pesticides:
Lambs quarter can be controlled with brominal. Mayweed chamomile is controlled with
2, 4-D and Banvel. Downy brome can be controlled with PowerFlex. Fall applied
herbicides provide greater control of downy brome than spring applied herbicides. Italian
ryegrass and wild oats are controlled with Far-Go and Hoelon. Black point and wheat
seed decay and damping off is controlled by destroying all volunteer wheat in the field
and seeding later in the season. Cephalosporium stripe is controlled by rotating with
spring grains. Wheat streak mosaic is vectored by the leaf curl mite and is controlled by
having a host free period between each cereal crop and by destroying all volunteer wheat.
The Hessian fly is controlled with seed treated with Gaucho or Cruiser. The Russian
wheat aphid, the bird cherry-oat aphid, the English grain aphid and the rose grass aphid
are controlled with seed treated with Gaucho and Cruiser or a foliar spray of Furadan, the
brown wheat mite and the leaf curl mite are controlled with Lorsban. The cereal leaf
beetle is controlled with Sevin. The wheat head armyworm is controlled with Sevin and
Lorsban. Grasshoppers are controlled with Sevin and Furadan. The leaf miner is
controlled with Aza-Direct. Nematodes are controlled through crop rotation and by
avoiding successive cereal or grass crops plantings. Fall planted crops will tolerate
damage more than spring planted crops. Wireworms are controlled with seed treated
with Gaucho of Cruiser.
Critical pest
control issues:
For seed production fields, a systemic seed treatment is recommended to help keep seed
borne pathogens out of seed stocks. The major uses of seed treatments are for control of
seed borne diseases, seed rots, seedling blights, root rot, insect control and foliar diseases.
Growers should use certified seed as a defense against disease. Growers should refrain
from planting wheat continuously in the same place; they should rotate crops and use
different herbicides. No conventional seed treatments should be used on organic seed.
Expert contacts:
Dr. Joe Yenish
Extension Weed Scientist
Washington State University
P.O Box 646420
Pullman, WA 99164
503 335 2961
Tim Murray
Department and Chair of Plant Pathology
Washington State University
Pullman, WA 99164-6430
509 335 9541
Keith S. Pike
Professor, Entomologist
Washington State University
24106 N. Bunn Rd
Prosser, WA 99350
509 786 9269
Location
of production: Adams, Benton, Columbia, Douglas, Ferry, Franklin, Garfield, Grant, Kittitas,
Klickitat, Lincoln, Spokane, Whitman Yakima, Lewis, Asotin, and Walla Walla counties.