Broad bean, Vicia faba, is a leguminous plant in the family Fabaceae primarily grown for its edible beans. Broad bean is a an annual vetch reaching between 0.5–1.8 m (1.6–6 ft) tall. There are often multiple stems originating from the base of the plant and the compound leaves are often broad, oval shaped, and come groups of 6 leaflets to a stem. The flowers are white with purple markings. Between 1 and 4 pods develop from each flower cluster. The beans can be greenish black, brown or black in color. Vicia faba may also be referred to as bell-bean, fava bean or horsebean and originates from the Mediterranean or in South-West Asia.
Broad bean is cultivated for both animal and human consumption, soil development, and medicinal uses .
It can be served fresh, dried, canned, or as a substitute for meat and skim-milk. Broad bean is often used as either forage (leaves, plant material) or silage (fermented, high-moisture fodder) for animals.
Using broad bean as a spring cover crop allows for protection against erosion, and can be tilled back into the soil as green manure. The taproot also has the added benefit of being able to break-up hard compacted soil.
Broad bean is a cool-season crop and should be grown in early Spring or late summer to avoid high summer temperatures. Broad beans will grow best at soil temperatures between 15.5 and 18.3°C (60–65°F) and will not grow well at temperature below below 4.4°C (40°F) or above 23.8°C (75°F). Broad bean is particularly susceptible to high temperatures during the summer which make the plants unproductive. Broad beans will grow best in a fertile, well-draining soil with a pH between 6.0 and 6.75 positioned in full sunlight.
Broad beans should be direct seeded in the garden in Spring as soon as the soil is workable and temperature is above 4.4°C (40°F) with the optimum temperature for germination being between 10 and 21°C (50–70°F). A second planting can be made in early Fall in areas with moderate winters. Seeds should be planted 2.5–5.0 (1–2 in) deep allowing 7.5–15 cm (3–6 in between plants and approximately 0.6 m ( 2 ft) between rows.
General care and maintenance
Broad bean plants are bush-like but can grow quite tall and will benefit from staking to provide some support and keep them from flopping over due to the weight of the pods. Keep soil moist during flowering to ensure optimum pod development and soak ground thoroughly if plants come into flower during a dry spell. As they are legumes, broad beans generally do not require additional fertilization as long as they have sufficient root nodules. Nodulation can be promoted by inoculating seeds with additional Rhizobacteria prior to planting.
Broad beans are ready to harvest when the pods are fat and full and beginning to droop from the plant due to the weight of the seeds inside. Seeds can be dried either by leaving pods on the plant until they begin to shrivel or by picking and hanging up to dry out.
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 plant
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; transmit viruses
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
Small, dark brown necrotic spots on leaves which may be surrounded by a zone of yellow tissue; water soaked spots on pods which turn brown and necrotic; pods may twist and distort in area of infection
Bacterium overwinters in crop residue; disease more severe when foliage is wet for extended periods
Plant only certified seed; rotate crops regularly; remove crop debris from field after harvest
Small, powdery dark spots on leaves and stems; dark brown spores on undersides of leaves; severe infestation can cause leaves to collapse and die
Emergence of the disease is favored by warm, humid cobditions; fungus overwinters on crop debris on the ground
Remove all crop debris after harvest; remove any infected leaves from the plant; apply an appropriate foliar fungicide to control the disease; avoid overhead irrigation; make use of trellises to open up the plat canopy and promote good air circulation around foliage; avoid excessive nitrogen fertilization
Symptoms of disease can be aggressive or non-aggressive; symptoms on non-aggressive chocolate spot are small red-brown lesions on leaves of the plant which may also be present on stems and pods; under high humidity the disease moves to the aggressive stage and lesions coalesce and become covered in fluffy mycelium; large patches of tissuy can become necrotic and die
Long periods of high humidity promote the switch from the non-aggressive phase to the aggressive phase; aggressive phase of the disease favors low levels of potassium and phosphorus in the soil and overcrowded plants
Control should be aimed at preventing the aggressive stage of the disease which can be achieved by lowering humidity; use appropriate plant spacings to encourage air circulation around plants; foliar fungicide applications throughout the season will protect the crop from chocolate spot
Yellow-brown blotches on upper surface of leaves; angular patches of fluffy white-gray fungus on lower side of leaves; plant growth may be stunted or distorted and whole plant may die before flowering; plant may produce
Fungus overwinters in soil and on crop debris; fungus can survive in soil for 10-15 years
Rotate crops for at least 5 years; till crop debris deeply; avoid sowing in late Autumn at greater soil depths as this can promote severe infections
Stunted plant growth; yellowing, necrotic basal leaves; brown-red or black streaks on roots that coalesce as they mature; lesions may spread above the soil line
Damage caused by the emergence of the disease is worsened by warm, compacted soils, limited soil moisture and poor soil fertility
Control relies on cultural practices e.g. do not plant broad in same area more than once in any 5 year span; treat seeds with an appropriate fungicide prior to planting
Water-soaked spots on leaves which enlarge and become necrotic; spots may be surrounded by a zone of yellow discoloration; lesions coalesce and give plant a burned appearance; leaves that die remain attached to plant; circular, sunken, red-brown lesion may be present on pods; pod lesions may ooze during humid conditions
Disease can be introduced by contaminates seed; bacteria overwinters in crop debris; disease emergence favored by warm temperatures; spread is greatest during humid, wet weather conditions
Plant only certifies seed; plant resistant varieties; treat seeds with an appropriate antibiotic prior to planting to kill off bacteria; spray plants with an appropriate protective copper based fungicide before appearance of symptoms
Thin, white, winding trails on leaves; heavy mining can result in white blotches on leaves and leaves dropping from the plant prematurely; early infestation can cause yield to be reduced; adult leafminer is a small black and yellow fly which lays its eggs in the leaf; larvae hatch and feed on leaf interior
Mature larvae drop from leaves into soil to pupate; entire lifecycle can take as little as 2 weeks in warm weather; insect may go through 7 to 10 generations per year
Check transplants for signs of leafminer damage prior to planting; remove plants from soil immediately after harvest; only use insecticides when leafminer damage has been identified as unnecessary spraying will also reduce populations of their natural enemies
Irregular patches of feeding damage on underside of leaves which causes the top surface of the leaf to dry out, giving the leaves a lacy appearance; insect will also damage flowers and small pods; pods may be damaged so badly that they drop from the plant; adult insect is an orange-brown beetle with black spots; larvae are fat-bodied grubs which taper at the end and are in rows of conspicuous spines
Beetles can decimate bean crops; beetles overwinter as adults and undergo 2-3 generations per year
Some bean varieties may be less attractive hosts for the beetle, e.g. snapbeans are preferred hosts over lima beans; early varieties may escape damage form beetles beetle populations can be reduced by remove overwintering sites such as brush and leaves on the ground; handpick larvae and adults; brush eggs from leaves and destroy; apply insecticidal soap to leaf undersides if infestation is heavy
Yellow spots on upper surface of leaves; powdery gray-white areas which coalesce to cover entire plant; if plant is heavily infected it may appear light blue or gray in color
Fungus overwinters on plant debris or alternate host; disease emergence is favored by warm, dry weather with cool nights that result in dew formation
Plant resistant varieties, particularly if sowing late; use overhead irrigation (washes fungus from leaves and reduces viability); plant crop as early as possible; frequent applications of sulfur may be required to control heavy infestations
Galls on roots which can be up to 3.3 cm (1 in) in diameter but are usually smaller; reduction in plant vigor; yellowing plants which wilt in hot weather
Galls can appear as quickly as a month prior to planting; nematodes prefer sandy soils and damage in areas of field or garden with this type of soil is most likely
Plant resistant varieties if nematodes are known to be present in the soil ;check roots of plants mid-season or sooner if symptoms indicate nematodes; solarizing soil can reduce nematode populations in the soil and levels of inoculum of many other pathogens
Leaves stippled with yellow; leaves may appear bronzed; webbing covering leaves; mites may be visible as tiny moving dots on the webs or underside of leaves, best viewed using a hand lens; usually not spotted until there are visible symptoms on the plant; leaves turn yellow and may drop from plant
Spider mites thrive in dusty conditions; water-stressed plants are more susceptible to attack
In the home garden, spraying plants with a strong jet of water can help reduce buildup of spider mite populations; if mites become problematic apply insecticidal soap to plants; certain chemical insecticides may actually increase mite populations by killing off natural enemies and promoting mite reproduction
If population is high leaves may be distorted; leaves are covered in coarse stippling and may appear silvery; leaves speckled with black feces; insect is small (1.5 mm) and slender and best viewed using a hand lens; adult thrips are pale yellow to light brown and the nymphs are smaller and lighter in color
Transmit viruses such as Tomato spotted wilt virus; once acquired, the insect retains the ability to transmit the virus for the remainder of its life
Avoid planting next to onions, garlic or cereals where very large numbers of thrips can build up; use reflective mulches early in growing season to deter thrips; apply appropriate insecticide if thrips become problematic
CABI Crop Protection Compendium. (2013). Vicia faba datasheet. Available at: http://www.cabi.org/cpc/datasheet/56364. [Accessed 07 November 14]. Paid subscription required.
Duke, J. A. (1983). Vicia faba L.. Purdue University Center for New Crops and Plant Products. Available at: http://www.hort.purdue.edu/newcrop/de.... [Accessed 07 November 14]. Free to access.
Schwartz, H. F., Steadman, J. R., Hall, R. & Forster, R. L. (2005) Compendium of Bean Diseases. Available at: http://www.apsnet.org/apsstore/shopap.... Available for purchase from APS Press.
Sattell, R., Dick, R. & McGrath, D. (1998). Fava Bean (Vicia faba L.). Oregon State University. Available at: http://ir.library.oregonstate.edu/xml.... [Accessed 07 November 14]. Free to access.