Buckwheat

Description

Buckwheat, Fagopyrum esculentum, is an herbaceous annual plant in the family Polygonaceae grown for its seeds which can be utilized in a manner similar to wheat or oats. The buckwheat plant is a fast growing, spindly, broad leaf plant with small heart-shaped leaves and hollow stems. The plant produces many small white or pink flowers which, when pollinated, quickly produce seeds. The seeds are triangular in shape and change from light green in color, to red-brown. The seed consists of a true seed (groat) which is surrounded by a thick hull. Buckwheat plants can grow between 40 and 120 cm (15.7-47.2 in) in height and survive for just one growing season. Buckwheat may also be referred to as qiaomei or ogal and was likely first domesticated from a wild ancestor in China.


Uses

Buckwheat can be used in the production of many foods in place of wheat e.g., pancakes, cakes and biscuits. It is also commonly used in breakfast cereals or it may also be blended into flour. The grain may also be used as fodder for animals. Buckwheat is an excellent cover crop, taking only 4–5 weeks from seed to flower and can protect against soil erosion and invasion by weeds.


Propagation


Basic requirements
Buckwheat grows optimally in temperate or sub-tropical climates where the temperatures are between 15–25°C but it may also be grown successfully in more tropical climates at higher elevation. Buckwheat will be killed by frost. In addition, the plants require a period of dry weather for harvest. Buckwheat can be grown in poor soils but will produce optimally in well-draining loamy soil. The plants will tolerate a wide pH range from 4.5 down to 7.0. It is a short-season crop and therefore does well when planted in the fall, stimulated by shorter day length.

Sowing
Buckwheat is grown by direct seeding and the seedbed should be properly prepared in advance of sowing. The soil should be fine but firm and dug to a depth of approximately 5 cm (2.0 cm) to aid in seedling emergence. Commercial fields are sown by mechanical drilling in rows spaced approximately 30 cm (12 in) apart but can simply be sown simply by broadcasting in the home garden. Seed should be scattered at a rate of about one pound of seed per 500 square feet of soil.

General care and maintenance
Buckwheat can be grown in nutrient poor soils and it does not require the addition of fertilizer.
If growing buckwheat as a cover crop it should be mowed down within 2 weeks of flowering to prevent the plants setting seed. The plant debris can be turned under the soil to decompose as green manure. Allow a few weeks between mowing and planting any new crops to allow the plant matter to decompose.


References

Björkman, T. (2010). Buckwheat Production: Planting. Cornell University Cooperative Extension. Agronomy Fact Sheet Series. Fact Sheet 50. Available at: http://nmsp.cals.cornell.edu/publicat.... [Accessed 07 November 14]. Paid subscription required.

CABI Crop Protection Compendium. (2013). Fagopyrum esculentum datasheet. Available at: http://www.cabi.org/cpc/datasheet/23844. [Accessed 07 November 14]. Paid subscription required.

Valenzuela, H. & Smith, J. (2002). Buckwheat. Sustainable Agriculture. Green Manure Crops. College of Tropical Agriculture and Human Resources, Univerisity of Hawai'i at Manoa. Avaialble at: http://www.ctahr.hawaii.edu/oc/freepu.... [Accessed 07 November 14]. Free to access.


Common Pests and Diseases

Damping-off (Root rot)
Rhizoctonia spp.

Symptoms
Failure of seedling to emerge; light brown, seedlings with light brown to redwater-soaked roots and stems; collapse of plants; plant dry up and die
Cause
Fungus
Comments
Occurs more often in cold temperatures when growth of seedlings is slow and in moist soil
Management
Treat seeds with fungicide prior to planting

Stem rot
Sclerotinia sclerotiorum

Symptoms
Small brown spots on stems; stems turn pale in color and become dehydrated; seeds fall off easily; stems eventually collapse
Cause
Fungus
Comments
Management
The collapsed plants are hard to spot in a field and the disease may not be discovered

Powdery mildew
Erysiphe polygoni

Symptoms
Light blotches on leaves; small necrotic areas on foliage near seed fill stage
Cause
Fungus
Comments
Disease favors warm, wet conditions
Management
No treatment possible; infections do not worsen and has no effect on yield

Aphids
Various

Symptoms
Small soft bodied insects on underside of leaves and/or stems of plant; usually green or yellow in color, but may be pink, brown, red or black depending on species and host plant; if aphid infestation is heavy it may cause leaves to yellow and/or distorted, necrotic spots on leaves and/or stunted shoots; aphids secrete a sticky, sugary substance called honeydew which encourages the growth of sooty mold on the plants
Cause
Insects
Comments
Distinguishing features include the presence of cornicles (tubular structures) which project backwards from the body of the aphid; will generally not move very quickly when disturbed
Management
If aphid population is limited to just a few leaves or shoots then the infestation can be pruned out to provide control; check transplants for aphids before planting; use tolerant varieties if available; reflective mulches such as silver colored plastic can deter aphids from feeding on plants; sturdy plants can be sprayed with a strong jet of water to knock aphids from leaves; insecticides are generally only required to treat aphids if the infestation is very high - plants generally tolerate low and medium level infestation; insecticidal soaps or oils such as neem or canola oil are usually the best method of control; always check the labels of the products for specific usage guidelines prior to use

Cutworms
Agrotis spp.
Peridroma saucia
Nephelodes minians
and others

Symptoms
Stems of seedlings may be severed at soil line; larvae causing the damage are usually active at night and hide during the day in the soil at the base of the plants or in plant debris of toppled plant; larvae are 2.5–5.0 cm (1–2 in) in length; larvae may exhibit a variety of patterns and coloration but will usually curl up into a C-shape when disturbed
Cause
Insects
Comments
Cutworms have a wide host range and attack vegetables including asparagus, bean, cabbage and other crucifers, carrot, celery, corn, lettuce, pea, pepper, potato and tomato
Management
Remove all plant residue from soil after harvest or at least two weeks before planting, this is especially important if the previous crop was another host such as alfalfa, beans or a leguminous cover crop; plastic or foil collars fitted around plant stems to cover the bottom 3 inches above the soil line and extending a couple of inches into the soil can prevent larvae severing plants; hand-pick larvae after dark; spread diatomaceous earth around the base of the plants (this creates a sharp barrier that will cut the insects if they try and crawl over it); apply appropriate insecticides to infested areas of garden or field if not growing organically

Aster yellows
Aster yellows mycoplasma

Symptoms
Flowers small, green, sterile; only a few plants are usually affected in a field
Cause
Mycoplasma
Comments
Spread by aster leafhoppers
Management
No preventative treatment; does not affect buckwheat yields