Dry bean production


Dr A J Liebenberg

Dry beans is at present regarded as one of the most important field crops in South Africa on account of its high protein content and dietary benefits.

Of all the annual leguminous food crops that are harvested for dry seeds, the ordinary bean is by far the most important. Dry beans (Phaseolus spp.) originated in Central and South America. Within the genus Phaseolus there are three species which are agronomically important in South Africa.

• Phaseolus vulgaris

Many different types and colours, the most important of which are: small white, red speckled or sugar beans, carioca and green beans

• Phaseolus acutifolius

Tepary beans

• Phaseolus coccineus

Large white kidney beans

Within each species there are many seed types which differ in size, shape and colour. Within each type there are different cultivars and the seeds of these cultivars differ very little from
one another. However, considerable differences may occur in adaptability, growth habit, disease resistance and many other characteristics. In this publication, only P. vulgaris is discussed, except where mentioned otherwise.


The dry bean is an annual crop which thrives in a warm climate. It grows optimally at temperatures of 18 to 24 °C. The maximum temperature during flowering should not exceed 30 °C for P. vulgaris and 26 °C for P. coccineus. High temperatures during the flowering stage lead to abscission of flowers and a low pod set, resulting in yield loss. Day temperatures below 20 °C will delay maturity and cause empty mature pods to develop. Cultivated under rainfed conditions the crop requires a minimum
of 400 to 500 mm of rain during the growing season, but an annual total of
600 to 650 mm is considered ideal.


Beans have to be planted in warm soils (minimum temperatures preferably above 13 °C) after all danger of frost has passed.

They grow well in soils with a depth of at least 90 cm, that have no deficiencies, and are well drained. Sandy loam, sandy clay loam or clay loam with a clay content of between 15 and 35 % is suitable. With sandy soils, problems of low fertility or nematode damage may occur.

Beans prefer an optimum soil pH (H2O) of 5,8 to 6,5, and are very sensitive to acidic (pH (H2O) < 5,2) soils (acid saturation above 10 %). They will also not grow well in soils that are compacted, too alkaline or poorly drained.


The National Dry Bean Cultivar Trials are conducted by the ARC_GCI annually and the information is published by the DPO in SA Dry Beans. Dry beans are classified into types according to:

Colour and seed size

• Small white beans (15-25 g/100 seeds), used mainly for canning purposes; 10 to 20 % of local production

• Red speckled or speckled sugar beans (red speckles on a beige background) (40-55 g/100 seeds); 65 to 75 % of local production

• Large white kidney beans (80-100 g/100 seeds); 5 to 10 % of local

• Carioca beans (khaki stripes on a beige background) 20 to 25 g/100 seeds);
3 to 5 % of local production

• Alubia beans (large white) (45-55 g/100 seeds); 1 to 5 % of local

Growth habit

• type 1: determinate or bush type

• type 2: indeterminate compact upright

• type 3: indeterminate runner type (short runners)

Growing season

Temperatures, especially during the night, determine the length of the growing season of a cultivar:

• short (85_94 days)

• medium (95_104 days)

• long (105_115 days).

A cultivar can have any combination of these characteristics. Further information on cultivars can be obtained from the ARC-GCI. Seed is produced by Dry Bean Seed (Pty Ltd) tel. (012) 325 1850 and PANNAR tel. (033) 413 1131.


For successful production, it is important that high-quality (certified) seed with a high germination percentage (80 % or higher) be used. This production cost factor is slight when compared to
probable yield losses due to disease or poor stand. Low-quality seed can cause a poor and an uneven stand, resulting in uneven maturity, harvesting problems and yield losses. Using disease-free seed will reduce the incidence of seed-borne diseases such as bean common mosaic virus (BCMV), bacterial diseases (common blight, halo blight and bacterial brown spot) and the fungal disease, anthracnose.

Other benefits of disease-free seed are that it is:

• labelled to indicate germination percentage

• guaranteed true to type and ensures homogeneity

• guaranteed free of weed seeds and foreign matter.


Seedbed preparation for the planting of dry beans follows the same pattern as that for any row crop planted in the spring. The seedbed must be deep, level and firm because this ensures better surface contact between the seed and the soil, increasing the absorption of moisture. A level seedbed also facilitates planting to a uniform depth.


It is recommended that beans be planted on soils which have been previously well fertilised. General fertility is more advantageous than direct fertilisation, because beans are sensitive to high concentrations of mineral salts.


The total withdrawal figure per 1 ton of dry bean seed produced is about 36 kg N, 8 kg P and 18 kg K.

Nitrogen (N)

Inoculation of dry bean seed is regarded as ineffective. Consequently, dry beans should be considered as incapable of satisfying all of their nitrogen requirements through N-fixation. The application of all the nitrogen at planting time is recommended, particularly where undecomposed material has been ploughed in before planting.

Deficiency symptoms

Lower leaves become light green and then yellow and eventually die. Young leaves may be lighter green than normal.

Guidelines for nitrogen application

Yield potential (t/ha) 




N fertilisation (kg/ha)




Phosphorus (P)

Under commercial production the yield responses to phosphorus fertilisation are not dramatic in dry beans and P is not normally a yield-restrictive factor. Under subsistence production, where small quantities of fertiliser are applied P can be a yield-limiting factor. Where the P content of the soil is lower than 20 ppm (Bray 1) it is recommended that superphosphate be broadcasted and ploughed into the soil to a depth of 15 to 20 cm before planting.

Phosphorus fertiliser must still be bandplaced at the time of planting. In low pH soils, phosphorus can be utilised efficiently by bandplacing 3,5 cm to the side and 5 cm below the seed.

Deficiency symptoms

Young leaves are small and dark green, older leaves senesce prematurely. Plants have short internodes and reduced branching.

Guidelines for phosphorus fertilisation

Soil analysis

P application for potential (t/ha)






P (mg/kg)

P fertilisation (kg/ha)



























Potassium (K)

When dry beans are grown on soils with a high clay content, potassium is not normally a limiting factor. Deficiencies are most likely to occur on sandy soils with an analysis of less than 50 ppm K. The optimum leaf content is 2 % potassium.

Deficiency symptoms

Bright yellow chlorosis of older leaves, appearing from the margins and then extending rapidly to the centre of leaflets.

Guidelines for potassium fertilisation

Soil analysis

K fertilisation for potential (t/ha)






K (mg/kg)

K fertilisation (kg/ha)



























Molybdenum (Mo)

If the soil has a pH (H2O) of less than 6, a seed treatment of 100 g sodium molybdate per 50 kg seed and/or a foliar spray of 100 g sodium molybdate per hectare should be given. If the pH (H2O) is below 5,3 and there are no Rhizobia in the soil, no results will be achieved by applying molybdenum.

Deficiency symptoms are similar to those of nitrogen because it is important for N metabolism.

Zinc (Zn)

The critical level of zinc in bean tissue is 15 to 20 ppm. Levels higher than 120 ppm can decrease yields. The availability of zinc is highest in slightly acid soils (pH 6,0-6,8) and lowest at pH(H2O) above 7,4.

Deficiency symptoms

Pale, yellow leaves, especially between veins and near the tips. The plants become deformed and dwarfed and may die. Pod formation is hampered and the plants are slow to mature.

Manganese (Mn)

Deficiencies only occur on soils with a high pH value. Symptoms include small leaves with a mosaic yellowing in the interveinal areas while the veins remain prominently green. Deficiencies can be corrected by applying manganese sulphate (MnSO4) at 15 to 20 kg/ha.

Boron (B)

Boron toxicity is a more frequent problem than deficiency and symptoms include chlorosis and dwarfing. With time, the chlorosis increases and resembles burn, with the leaf margins curling in. Beans should not follow a sunflower crop which has received boron fertiliser.

Iron (Fe)

Deficiency occurs on calcareous or saline soils where pH (H2O) values are above 7,4. Symptoms are characterised by bright yellow leaves and green veins. Deficiencies can be rectified by a 1 % FeSO4 solution or chelate applied as a foliar spray.


The optimum soil pH levels for dry beans are:

• pH (H2O): 5,8_6,5

• pH (KCl): 4,8_5,5.

The percentage of acid saturation has to be lower than 10 % for the cultivation of dry beans. The soluble aluminium content has to be less than 25 to 30 %.

The pH can be raised (acid saturation reduced) by applications of agricultural lime. These applications to acid (low pH) soils can make certain micronutrients, such as molybdenum, more available to the plant. The availability of phosphorus is influenced by the pH. It is readily available at a pH (H2O) of 6 to 7.

Calcium and magnesium deficiencies can be alleviated with agricultural lime. High pH soils are often associated with an excess of sodium salts which reduce nutrient uptake. Beans will tolerate a sodium saturation percentage of up to 8 or 10 and an electrical conductivity of up to 1 mmho/cm.


The most suitable planting date is determined by the following factors:

• Correct soil temperature

• Probability of heavy rain which may lead to soil crusting and restrict seedling emergence

• Possibility of high temperatures later in the season which may cause blossom drop

• Length of the growing season (high temperatures during flowering, rain during harvest and frost damage should be avoided)

• Crop rotation programmes (position of the bean crop in the total crop setup, i.e. planted after another crop, such as maize).

Planting dates are mainly restricted by the possible occurrence of frost (planting too late), and rain at harvesting, resulting in poor quality (planting too early). Planting dates in South Africa range from November to mid-January in areas where frost occurs. In frost-free areas, March and April are the best months for planting beans. The large white kidney bean (P. coccineus) is an exception and is planted from mid-November to mid-December and is not adapted to winter production.


The between-row spacing for all types of beans under commercial production is 900 mm because dry beans are usually cultivated in rotation with maize. For early maturing cultivars, especially those with a determinate growth habit, a row spacing of 750 mm is recommended if mechanisation is practical (see table).

Spacing and plant population


within rows

between rows

Plant population

Early maturing,



177 000

Medium and late



150 000

Large white



115 000

Planting depth is determined by the soil texture and its moisture content. Generally the seeds are placed 2,5 to 5,0 cm below the soil surface.


Irrigation offers the potential for increasing yields and enabling production in otherwise unsuitable soils. Sprinkler irrigation is the most frequent means of irrigation for dry beans. The system used is determined by the size and shape of the lands, as well as available labour and capital. In areas where water is unrestricted (not merely supplementary irrigation), the soil should be wet to field capacity to the depth of the 1 m root zone before planting. As soon as the soil is sufficiently dry, the seedbed should be prepared and planted and thereafter the field should not be irrigated until the seedlings have emerged.

Irrigation scheduling is essential for optimum yield per unit of water. The critical, moisture-sensitive growth stages are flowering and early pod set which occur at 40 to 50 % and 50 to 60 % of the growing season. It is important that irrigation cycles be correctly scheduled, because excess moisture can create conditions conducive to root rot and Sclerotinia. Moisture stress can also aggravate some root rots such as Fusarium oxysporum. Irrigation should cease when a quarter of the bean pods have turned yellow. For the correct irrigation scheduling, expert advice must be obtained.


Dry beans have a moisture content of about 50 % at physiological maturity.

The beans, however, are only ready for harvesting when the moisture content drops to 16 %, the ideal being 15 %. Seeds may split during threshing when the moisture content is less than 12 % and such seeds are rejected by canners and seed companies. It is difficult to clean without further seed split or broken seed coats. Dry beans should be harvested when all the pods have turned yellow, but before they have become so dry that the pods begin to shatter.

Dry beans can be harvested as follows:

• Handpulling and threshing by driving a tractor over them on a threshing floor. Smaller volumes can be threshed by hand by beating with a stick covered in a hessian sack. The wind can be used to separate the seed from the chaff

• Partially mechanised systems, where the plants are pulled up by hand, placed in windrows and threshed with a harvester or stacked, whereafter they are threshed with a stationary threshing machine

• Fully automated system with mechanical pulling. The beans are raked into windrows and threshed by means of an automated combine.


• Pulling of beans should start when the moisture content of the pods is temporarily high (to prevent shattering), i.e. early in the morning before the dew has evaporated.

• Mechanised harvesting must be done when there is no danger of crop damage by rain.

• To prevent cracking and splitting beans should be threshed at slow cylinder speeds with a machine equipped with an axial flow threshing mechanism.


Effective weed control is a prerequisite for high dry-bean yields. Dry beans, being low-growing plants, struggle to compete with or overshadow weeds. Early control is extremely important, because the root system of the plant develops at this stage and some weeds secrete chemical inhibitors which limit plant growth. At a later stage weeds hamper the harvesting and threshing processes, adversely
affecting the quality of the crop.

Mechanical weed control

Mechanical weed control should begin during seedbed preparation (remove all weeds) and be repeated with a tiller between the rows when necessary up to the flowering stage. Care should be taken that implements do not damage the crop by using row spacings which permit easy access and taking care that roots are not damaged. Cultivation between the rows is also advantageous because it loosens the soil and improves aeration and water penetration. Weeds in the row have to be handpulled.

Chemical weed control

Chemical weed control can be implemented before planting or before and/or after emergence. A sufficient number of herbicides have been registered to control all weeds throughout the entire growing period of dry beans. Information in this regard is obtainable from the different agrochemical companies.


Diseases and pests may have been partially responsible for the unstable production that has been experienced in the past. Incidence and severity vary between seasons because of environmental and management practices. Integrated disease and pest management, using all suitable control measures, is recommended.

Causal organism, symptoms, ideal conditions, prevention and treatment of important dry-bean diseases

Disease Causal organism  Symptoms Ideal conditions Prevention/treatment

Angular leaf spot


Dark grey to brown angular lesions on leaves. Small spore-carrying organs resembling beard stubble on underside of lesions. Severe infection leads to leaf yellowing and defoliation. Large, round, flat, reddish lesions on pods and elongated dark brown lesions on stems

Moderate to hot, prolonged periods of high humidity

Plant resistant cultivars; especially small seeded; work bean debris into the soil after harvesting



Brick-red to purplish darkening of veins on lower leaf surface. Brown lesions, becoming sunken with a reddish-brown border, on pods. Dark lesions (various sizes) on seeds

Cool and humid

Plant disease-free seed; work bean debris into the soil after harvesting; restrict movement in field; apply suitable fungicides; crop rotation with non-hosts (beans every 3-4 years)


Phoma exigua

Dark brown to black concentric lesions on leaves and pods. Can cause ragged leaves and defoliation

Cool to moderate and humid

Work bean debris into the soil after harvesting; apply suitable fungicides

brown spot

Pseudomonas syringae pv. syringae

Leaf symptoms are small, irregular brown spots which are sometimes surrounded by a light-green zone. Older leaves have a tattered appearance. Pod symptoms are small, dark-brown sunken lesions. Infection of pods at an early stage, inhibits growth at the point of infection, which results in malformation and twisting of pods. Beans without visible symptoms can harbour substantial populations of the pathogen

Moderate temperatures, humid

Plant disease-free work bean debris into the soil after harvesting: apply copper-based bactericides as a preventive measure; control weeds and volunteer beans


Bean common mosaic (necrotic) virus

Both diseases cause dark-green vein banding, downward curl of the leaves and leaf malformation. Leaves have an arched, puckered and blistered appearance and look thinner. BCMNV causes systemic necrosis (black root) in plants containing the I-gene

Presence of infected sources, aphids and susceptible cultivar

Plant resistant cultivars/disease-free seed; plant early to avoid large aphid populations; control aphids with suitable pesticide

Charcoal root rot (Ashy stem blight)

Macrophomina phaseolina

Small, sunken black lesions on stems at soil level, spreading upward to blacken lower stems. Foliage may yellow, wilt and die off. Minute black dots (pycnidia) barely visible on blackened stems. More conspicuous on mature plants

Hot and dry

Seed treatment with suitable fungicides (only effective at an early stage); flooding or very wet conditions for a few weeks before planting; good irrigation; work in bean debris after harvesting. Crop rotation has limited value because maize, sorghum and small-grain crops are also hosts



Leaf symptoms appear as large, brown necrotic lesions surrounded by a narrow, bright yellow margin. Pod symptoms are circular, slightly sunken, dark reddish-brown lesions. Seeds directly connected with pod lesions may be discoloured

Hot and humid

Plant disease-free seed; work bean debris into the soil after harvesting; apply copper-based bactericides as a preventive measure; control weeds and volunteer beans

root rot (dry root) rot)

Fusarium solani
f. sp phaseoli

Elongated reddish discoloration of the taproot, (root may rot completely), Plants may become stunted, show premature defoliation and evenually die. Secondary roots near the soil surface. Infection most severe when the root system is under stress

Stress conditions, especially drought. Pathogen occurs in most soils and may be spread in soil dust (wind)
or on seeds)

Crop rotation with maize or other grain crop; deep ploughing; avoid stress, poor nutrition and damage to stems (by for example bean fly, hoeing, machinery); use tillage which minimises soil compaction

Fusarium yellows
(F. wilt)


f. sp. phaseoli

Visible in field as groups of yellowing plants. Leaves become yellow and die off. Internal discoloration of lower stem (vascular tissue). Younger plants stunted, may wilt and die

Hot and dry, stress conditions

Crop rotation with grain crops (maize, wheat, etc); deep ploughing; avoid stress and damage to stems (by for example bean fly, hoeing, machinery)

Halo blight

Pseudomonas savastanoi pv phaseolicola

Leaf symptoms initially appear as small, water-soaked lesions on the underside. Lesions turn reddish brown and become necrotic with age. The most characteristic symptom is a light-green zone (halo) surrounding the necrotic spot. Pod symptoms are greasy, water-soaked spots of various sizes. Lesion margins may turn brown as they mature. Lesions normally stay green on dry pods. Plants with infected vascular systems (systemic infection) appear stunted, generally showing a lime-green colour and a reddish discoloration at the nodes

Cool and humid

Plant disease-free seed; work bean debris into the soil after harvesting; apply copper-based bactericides as a preventive measure; control weeds and volunteer beans

Powdery mildew

Erysiphe polygoni

Originally faint blackened superficial starlike blotches, becoming white, coalescing to cover aerial parts in a dry powdery film.
Plants may dry out and become defoliated

Hot and moderately humid

Resistant cultivars, suitable fungicides


Pythium spp

Poor emergence, wilting and dying off of young seedlings. Water-soaked, then grey to brown lesions near soil surface, spreading to stems and roots and leading to soft rot. Areas in rows with dead plants bordered by stunted plants. In severe cases, large areas may be affected

Cool and wet conditions

Seed treatment with suitable fungicides; good drainage; crop rotation

*Rhizoctonia root rot

Rhizoctonia solani

Reddish-brown lesions on lower stems, becoming sunken and spreading to cause wilting and dying off of plant. Often more severe at seedling stage but may cause stunting and uneven maturation in older plants

Moderate to high soil moisture and temperatures

Seed treatment with suitable fungicides; good drainage; deep ploughing; shallow planting; crop rotation


Uromyces appendiculatus

Small, white spots develop on leaves, (sometimes only on underside), lesions enlarge and burst open to form raised, rust-coloured pustules releasing a reddish-brown dust (spores) when rubbed. Spores may become black at end of season. Pustules sometimes surrounded by yellow halo or necrotic (dead) tissue. Leaves may yellow and die off. Pustules on pods elongated.

Moderate temperatures, alternate wet and dry periods, windy

Resistant cultivars; suitable fungicides; work in plant debris after harvesting; re-move volunteer beans


Elsinoë phaseoli

New leaves and shoots curl upwards. On older leaves, grey to light-brown circular scab-like lesions, usually concentrated near the veins. Similar lesions, darkening with age, on the pods

Hot and humid

Plant disease-free seed; plant resistant cultivars; apply suitable fungicides

Sclerotinia (white mould)

Sclerotinia sclerotiorum

Early symptoms small, water-soaked spots on leaves and stem, followed by white masses of mycelium. Sclerotia form on this mass and turn black after 7-10 days. Dried out infected tissue have a characteristic bleached appearance

Humid, dense leaf canopy

Crop rotation with maize; use disease-free seed; schedule irrigation cycles so that plants do not remain wet for long periods; avoid overirrigation; apply suitable fungicides

*Sclerotium root rot (southern blight)

Sclerotium rolfsii

Grey water-soaked lesions, becoming brown, near the soil surface, spreading to the taproot and leading to wilting and death of the plant. Lower leaves may also be affected. Characteristic small round light-yellow to brown sclerotia and white fungus growth
visible on established lesions.

Dry weather followed by hot and humid

Good drainage; crop rotation; work in bean stubble after harvesting; deep ploughing

* Diseases of the roots and stem, known as "root rot", often occur in a complex and can include any of the following: fusarium, pythium, rhizoctonia, charcoal rot and sclerotium root rot (Southern blight), the first three being the most frequent. The latter four can also cause rotting of seed and damping off. To some extent root rot can be prevented, but not treated. Fungicides can only be applied to seed as a preventive measure against Pythium and Rhizoctonia root rot



Scientific name 



Black bean aphid

  Aphis fabae  

Vectors of various viruses 

Apply suitable insecticide

Groundnut aphid 

Aphis craccivora 

Vectors of various viruses 

Apply suitable insecticide

Tobacco whitefly 

Bemisia tabaci  

Potential vector of bean 

No insecticide currently
golden mosaic virus registered

Tobacco leafhopper

Jacobiella fascialis  

Suck sap from leaves 

No treatment necessary

Bean seed maggot 

Delia platura  

Maggots attack cotyledons, 

Control with a seed dressing mine into stems below soil insecticide level and pupate

Bean stem maggot 

Ophiomyia spencerella Ophiomyia phaseoli  

Maggots mine into stems and pupate 

No insecticide currently  registered

Spotted maize beetle 

Astylus atromaculatus  

Feed on pollen, destroy 

No insecticide currently flowers registered

CMR beetle 

Mylabris oculata  

Destroy flowers 

Apply suitable insecticide

Black maize beetle 

Heteronycus arator  

Damage stems on or beneath 

Apply suitable insecticide soil surface

Chafer beetle 

Adoretus cribrosus Adoretus tessulatus

Feed on young leaves, petals and pollen

Apply suitable insecticide

Bean bug 

Clavigralla tomentosicollis  

Suck sap from leaves, stems and pods—cause wilting of developing pods

No insecticide currently registered

Tip wilter 

Anoplocnemis curvipes  

Suck sap from stems—cause wilting and dying of tips of shoots

No insecticide currently registered

Green vegetable bug 

Nezara viridula  

Suck sap from pods—cause browing of seeds inside 

No insecticide currently registered

Common cutworm 

Agrotis segetum  

Damage stems on or beneath soil surface

Apply suitable insecticide

African bollwurm 

Helicoverpa armigera  

Feed into pods and damage 

Apply suitable insecticide seeds

Cabbage semi- looper 

Trichoplusia orichalcea

Feed into pods and damage seeds

Apply suitable insecticide

American leafminer

Liriomyza trifolii  

Larvae tunnel into leaves 

Apply suitable insecticide

South American leafminer/Potato leafminer

Liriomyza huidobrensis  

Larvae tunnel into leaves 

No insecticide currently registered

Bean flower thrips


Feed in flowers, causing a roughened, silvery texture on pods

Apply suitable insecticide

Bean thrips 

Sericothrips occipitalis

Feed in flowers, causing a roughened, silvery texture on pods

Apply suitable insecticide

Bean weevil 


Larvae enter seed and hollow it out by feeding

Apply suitable insecticide

Bean gall weevil 

Alcidodes erythropterus  

Larvae enter stems, pupate in the galls formed

Apply suitable insecticide



For further information on bean production contact:

• ARC-Grain Crops Institute (ARC-GCI) Private Bag X1251
Tel. (018) 299 6100

• Dry Bean Producers' Organisation (DPO)
P.O. Box 26269
Tel. (012) 325 1850

and subscribe to SA Dry Beans,
a quarterly magazine.

The Dry Bean Production Manual can also be ordered from the same address.


M J du Plessis
D Fourie
A J Liebenberg
M M Liebenberg
C J van Zyl


Information provided by
ARC-Grain Crops Institute (ARC-GCI)
Private Bag X1251, Potchefstroom 2520
Tel. (018) 299 6100

Compiled by Directorate Agricultural Information Services, Department of Agriculture
in cooperation with
ARC-Grain Crops Institute

Printed and published by Department of Agriculture
and obtainable from Resource Centre, Directorate Agricultural Information Service,
Private Bag X144, Pretoria 0001 South Africa