East African Seed Co. Ltd. Africa’s Best Grower’s Guide www.easeed.com
Green peas. www.agriculture.kzntl.gov.za
Hagedon, D.J. (Ed) (1984). Compendium of Pea Diseases. American Phytopathological Society Publication. ISBN-13: 978-089054602.
Horticultural Crops Development Authority (HCDA). Export Crop Bulletin: No 1. June 1996. Snowpeas (Pisun sativum). Leguminosaceae.
Mark Gaskell. Edible-pod pea production in California. Vegetable and Information Center. Vegetable Production Series. ISBN: 978-1-60107-024-1. www.anrcatalog.ucdavis.edu
Ministry of Agriculture (2006). Economic Review of Agriculture. Republic of Kenya.
Muehlbauer, F.J.,Tullu, A. (1997). New crop fact sheet. Pisum Sativum L. www.hort.purdue.edu
Myers, J.R., Colt, W.M., Swanson, M.A. (1994). Beans and Peas. A Pacific Northwest Extension Publication, Idaho, Oregon, Washington. www.cals.uidaho.edu
NSF Center for Integrated Pest Managment. Crop profile for peas (green) in Idaho
Nutrition Data www.nutritiondata.com.
Ohio State University. Ohio State University Extension Fact Sheet Horticulture and Crop Science: www.ohioline.osu.edu
PIP. Technical Itinerary Pea. With technical collaboration of Louis Labuschagne of Real IPM. PIP-COLEACP, Brussels, Belgium. www.coleacp.org
Purdue University. Center for New Crops & Plant Products. www.hort.purdue.edu
Sherf, A.F., MacNab, A.A. (1986). Vegetable Diseases and Their Control. A Wiley-Interscience Publication. ISBN: 0 471 05860 2.
Groundnut hopper Hilda patruelis. Size is about 5 mm in length (c) ICRISAT
It is about 5mm in length, brown or green in colour with white marks and strips on the wings. The nymphs resemble the adults but without fully developed wings.
These insects live in clusters or colonies, and are attended by ants that feed the honeydew excreted by the hoppers. These sucking insects attack the plants at the base of the stem, usually below ground level.
The toxic saliva injected while feeding causes the plant to wither, turn yellow and die.
The extent of damage can be important when the insect occurs in large numbers. The first sign of infestation is the presence of black ants.
What to do:
Use
tolerant or resistant varieties. The groundnut variety “Nyanda” is
reported to be tolerant to aphids and to the groundnut hopper (IAN,
2003).
Millipedes are brown to blackish in colour and curl-up when disturbed. (c) Courtesy EcoPort (http://www.ecoport.org) : Agricultural Research Council of South Africa
Millipedes are among the economically important soil pest of groundnuts. They are brown to blackish in colour and curl when disturbed.
They attack groundnut seedlings, between planting and approximately 20 days after planting, feeding on the emerging cotyledons and moving to the root system at the collar region.
The cortex is often damaged serving as an entry point for secondary infection by microorganisms. The development of plants surviving the attack is often retarded.
Millipedes also attack maturing groundnut during pod formation, i.e. when the pods are still soft.
Immature pods from severed pegs are often perforated and thus suffer secondary infection or invasion by rot-causing organisms such as Aspergillus flavus.
Millipedes may also damage flowers. Birds are main predators of millipedes.
What to do:
Practise good sanitation.
Prepare land properly.
Select sites away from forest (breeding sites for millipedes).
Peas are susceptible to a large number of aphid- transmitted viruses, which can produce diseases individually or in combination. The main viruses infecting pea are pea enation mosaic, pea streak and bean yellow mosaic.
Pea enation mosaic virus (PEMV)
Symptoms of pea enation mosaic virus-1 or also called pea virus 1 (c) Courtesy of: The Food and Environment Research Agency (Fera) , Crown Copyright
In addition to pea, PEMV also infects broad bean, sweet pea, and alfalfa. It probably overseasons in many common perennial legumes. The virus is spread in nature most efficiently by the pea aphid (Acyrthosiphon pisum) and to a lesser extent by the green peach aphid (Myzus persicae). The virus is transmitted in a persistent (circulative) manner. Infected pea plants develop mosaic and chlorotic vein flecking (appears as translucent windows) and veinal enations (blisterlike outgrowths), which are very characteristic for pea enation mosaic virus. Plants are stunted, and proliferation of basal branches is common. Pods are distorted, split open, and may show prominent enations.
Termites(Coptotermes formosanus) (c) A. M. Varela, icipe
Termites are serious groundnut pests throughout the southern African region and West Africa.
Species of Microtermes and Odontotermes are the most damaging, while Macrotermes cause occasional damage.
The small-sized Microtermes spp., in particular, attack and invade growing groundnut plants through the roots and stem near ground level, hollowing them out and causing the plants to wilt and die with a consequent reduction in crop stand.
Roots damaged by other soil pests, such as white grubs, are also prone to attack by termites. Some termite species (Macrotermes spp., Hodotermes mossambicus) cut off stem bases, and may cause 25-100% of plant losses.
As the crop ripens the outer layers of the pods are scarified (removal of soft corky tissue between the veins of the pod) by termites allowing contamination of the seed with soil fungi,such as Aspergillus flavus, which produce lethal “aflatoxins”.
Scarification of pods is by far the most common type of termite damage at plant maturity, a factor often aggravated by late harvest.
Scarification as high as 30% has been reported. Infested plants are not obviously diseased and are frequently harvested and contaminate the rest of the crop.
Species such as Microtermes spp. also penetrate the pod to feed off the soft inner lining, filling the pod with soil. This form of attack leads to additional loss through premature germination of kernels.
Stacks of plants left drying in the fields are also frequently attacked by species such as Odontotermes spp. with farmers losing between 30-40% of their crop at this stage.
Termite damage is generally most serious towards the end of the growing season just prior to harvesting, and it is particularly serious during periods of drought (ARC/LRN. 2007).
What to do:
Remove
residues of previous cereal crops (sorghum, millet and maize). Plant
residues left in the field serve as food for termites, which may infest
the new crop. Termite infestation of 100% has been observed in groundnut
crops with high plant residues.
Planting should be carried out
early enough to avoid drought periods. Moisture deficiency may stress a
crop and lead to attack by termites due to low vigour.
Harvest
promptly. Research has shown that termite damage increases with delay in
harvest. Furthermore, most groundnut-producing areas in sub-Saharan
Africa experience drought and high temperatures during the later part of
the growing season, conditions that favour termite infestation as well
as fungus (A. flavus) infection of pods leading to aflatoxin formation in seeds.
The complete destruction of mounds and removal of queen termites are effective control measures against mound-building species (Macrotermes
spp.). Partial destruction of mounds is unlikely to solve the problem,
since replacement reproduction may develop from the remaining termites.
It
has been reported that close spacing in groundnut helps to deter
termite infestation, although the reason for this was not given.
However, high density sowing, followed by thinning of surviving plants
where necessary to reduce competition, offsets anticipated losses due to
termites.
Chafer grub( Schyzonycha spp.) (c) A. M. Varela, icipe
Whitegrubs are the larvae of scarab “chafer” beetles. They are white, C-shaped with a brown head and three pairs of legs.
Many species of white grubs are associated with groundnut damage in parts of sub-Saharan Africa. The most important are Schyzonycha species.
White grubs attack plants at all stages of growth. They eat roots and damage pods of groundnuts.
White grubs feed mainly on the taproots and/or peripheral roots leading to stunting or death.
They inflict cuts in the crown region of taproots; these lesions are often invaded by rot-causing fungi.
White grubs also cut out pods from the base of groundnut pegs and destroy larger, soft pods.
Plants are often attacked in a row. White grubs seem to prefer soils with sandy or loamy sand textures and are seldom observed in clay soils.
What to do:
Allow enough time between manure application and planting of groundnut. The excessive use of organic manure in groundnut farms has been observed to increase the incidence of white grubs, especially when manure is applied during the cropping season.
Deep ploughing or hand hoe tillage exposes soil pests to desiccation and to predators, thus helping to reduce their numbers and damage.
Other pests: Broomrape, Sedges, Snails (Giant East African Snail)
Geographical Distribution in Africa
Geographical Distribution of Groundnut in Africa. Updated on 8th July 2019. Source FAOSTAT
General Information and Agronomic Aspects
Groundnuts originated in South America from southern Bolivia to north-western Argentina. The Portuguese apparently took them from Brazil to West Africa and then to south-western India in the 16th century.
Africa is now regarded as a secondary centre of diversity. Groundnuts are now grown in most tropical, subtropical and temperate countries between 40degN and 40degS latitude, especially in Africa, Asia, North and South America.
Groundnuts are a small erect or trailing herbaceous legume, about 15 to 60 cm high. The fruit is a pod with one to five seeds that develops underground within a needle-like structure called a peg.
The seeds are rich in oil (38-50%), protein, calcium, potassium, phosphorus, magnesium and vitamins. Groundnuts have also considerable medicinal value.
They are reported to be useful in the treatment of disease such as haemophilia, stomatitis, and diarrhoea.
Most of the world production of groundnuts is crushed for oil that is used mainly for cooking.
The press cake from oil extraction is a feed rich in protein but is also used to produce groundnut flour, which is used in many human foods.
The seeds or kernels are eaten raw, boiled or roasted, made into confectionery and snack foods, and are used in soups or made into sauces to use on meat and rice dishes.
The vegetative residues from the crop are excellent forage. In sub-Saharan Africa, groundnuts are a basic staple crop, cultivated mainly by small-scale farmers both as subsistence and as a cash crop.
It is an important source of protein and other nutrients for poor rural communities.
In Africa, groundnut yields are traditionally low, due to unreliable rains, little technology available to small-scale farmers, pest and disease occurrence, poor seed variety, and increased cultivation on marginal land (ICRISAT).
Climatic conditions, soil and water management
Groundnuts are grown in the warm tropics and subtropics below 1500 m above sea level, and in temperate humid regions with sufficiently long warm summers. Optimum mean daily temperature to grow is 30degC and growth ceases at 15degC.
Cool temperatures delay flowering. Groundnuts cannot stand frost. Between 500 and 600 mm of water reasonably well distributed through the growing season allows a good production.
Nevertheless, groundnuts are a drought-tolerant species and can withstand severe lack of water, but yield is generally reduced.
If harvesting conditions are wet, aflatoxins (severe poison produced by some fungi such as Aspergillus spp. may develop on the nuts. Aflatoxin contamination is a major hazard to human and animal health.
When thee groundnuts are poorly dried and stored, they pick mold and dirt, which attracts a fungi,
that releases aflotoxin chemicals that are dangerous to human health especially the liver.
Because pods develop underground and must be recovered at harvest, crumbly, well-drained soils are preferred, but plants grow and develop adequately on heavier clay soils.
For optimum growth, soil pH should be in the range 5.5 to 6.5, though Bunch types tolerate more acid conditions (pH 4.5) and some cultivars grow well in alkaline soils up to pH 8.5.
Propagation and planting
Ideally the seedbed should be deep and friable with an even particle size. Take care that the seedbed is weed-free.
Cloddy and uneven seed beds can result in uneven emergence and heavy losses of plants.
Recommended plant densities are near 200,000 to 250,000 plants/ha for the typically short-season Bunch cultivars. In most countries, cultivation is in rows with plant spacing ranging from 40 x 20 cm to 30 x 20 cm.
After ploughing and harrowing to a fairly good tilth, ridges, which are 80 cm apart with flattish tops, should be made so that two rows of nuts can be planted on each ridge.
Seeds for planting should be well selected: they should be clean, well filled and without any blemishes. Seeds for planting should be kept in their pods and shelled a few days before planting.
Planting depth is like maize about 5 to 8 cm. Seed rate is 40 to 50 kg/ha depending on the size of the seeds.
There are 2 types of groundnuts:
Bunch type
Runner type
Bunch varieties such as Red Valencia mature within 90 to 100 days, while runner types such as “Homa Bay” mature in 120 to 150 days (require a longer growing season).
Table: Groundnut varieties and mean kernel yield
Variety
Mean kernel yield Kg/ha
“Red Valencia”
1500
“Severe 116” (white)
1250
“Texas Peanut”
1360
“Bukene”
1530
“Manipintar”
2450
“Makulu Red”
2720
“Altika”
900
“Homa Bay”
770
“Asirya Mwitunde”
1300
With good husbandry current farmers’ yields of between 450-700 kg/ha could be doubled.
Intercropping
Groundnuts are grown as a sole crop and also intercropped with maize, soybean and cassava. It is also a good intercrop for upland rice, sorghum, okra, sugarcane, and sunflower.
To get a good yield however, proper planting distance should be observed along with the other recommended cultural practices.
In some areas, they are grown under perennial tree crops such as coconut, oil palm or rubber.
Groundnuts when used as intercrop for upland maize and planted along the contour reduce soil runoff. The plant also reduces population of African bollworm because it serves as a hiding place for beneficial insects.
(OISAT) There is an increase in the yield of groundnuts when intercropped with early maturing pigeon pea.
Husbandry
To achieve maximum economic yields, weeds must be eliminated. Groundnuts are very poor competitors with weeds during early stages of growth.
Weeding should be done early while at the same time earthing up the ridges to encourage “pegging” i.e. young nuts penetration through the soil.
Once pegging has started, only hand weeding should be undertaken to avoid disturbing the young nuts or damaging the flowers. Clean weeding should be done up to 6 weeks after which hand weeding should take over.
The only peculiar nutrient requirement is for calcium (Ca) in the podding zone. Calcium is absorbed directly by the pods, if soil moisture is adequate. A shortage of Ca in that zone will result in empty pods (especially in Runner cultivars).
The crop’s needs for nitrogen should be satisfied with symbiotic fixation by strains of Rhizobium of the cowpea group, so nitrogen fertilisers are not generally required. In some areas of acid soils, lime is applied to raise the pH and supply Ca.
Moisture stress during flowering or pod filling reduces yield so that irrigation during those periods to minimise or eliminate the stress increases production and seed quality.
Where yields are unsatisfactory (heavily eroded soils) an application of 200 kg/ha of rock phosphate is recommended.
Harvesting
Bunch cultivars are harvested 85-100 days after sowing and Runner cultivars 110-130 days after sowing in the warm tropics. Dig a few plants up to see if the nuts are ready.
The nuts should be brown on the outside, firm and dry. Usually at maturity the inside of the pods is grey and some rattling occurs when pods are shaken.
Severe disease of foliage sometimes results in harvesting before seeds are fully mature.
Plants should be carefully dug out to avoid nuts breaking off and remaining in the ground.
Dry for 2-3 days, then rip the pods from the bushes and place them on mats to dry for another 7-10 days to about 10% moisture.
Shelling should be done by hand. Broken, dirty or damaged nuts should be discarded as these will lower the quality and hence the selling price.
When thee groundnuts are poorly dried and stored, they pick mold and dirt, which attracts a fungi that releases aflotoxin chemicals that are dangerous to human health especially the liver.
Nuts to be used as seed the following year should not be shelled.
Ascochyta pisi, A. pinodella/Mycosphaerella pinodes
Credits-Biovision-Infonet
Ascochyta spots on snowpea pea pods (c) A.A. Seif, icipe
Ascochyta spots (here on snowpea leaves) (c) A.M. Varela, icipe
Ascochyta blight attacks all parts of the plant. The infected leaves have small to large, round to irregular, dark brown to purple spots. Some of the spots may have ashy grey centres. The spots usually have purple margins and may have rings. Spots may join up to form brownish purple blotches. Severely diseased leaves shrivel and dry, starting at the base of the plant and progressing upwards. Spots on pods are sunken but have no rings. Stem symptoms consist of brownish to purple streaks. Infection from infected seeds can cause a brown to black stem and foot rot just above the soil line. Such plants may die and result in a poor stand in the field. Blossoms may be infected and drop off during extended wet weather.
The disease is favoured by cool wet weather, heavy dews in the morning and relative humidity above 89%.
What to do:
Use certified disease-free seeds.
Use resistant varieties.
Plough deeply pea stubble after harvest.
Remove crop residues from the field after harvest.
(Sericothrips spp, Frankliniella occidentalis, and Thrips tabaci)
Credits:Biovision-Infonet
Pigeon peas infested by thrips (c) A.A. Seif
Thrips damage on snowpea (c) A.M. Varela, icipe
Thrips suck plant tissues causing withering of the plant. Infested parts show silvery white discolouration. Thrips feeding on pods cause tinny scars and blemishes. The damaged pods may not be noticed at harvest, but scars become more visible during post harvest transport to market. Thrips damage lowers the market value of snow peas and sugar snaps (which are eaten as pods) and may lead to rejection. Their feeding punctures may also be a point of entry for disease-causing fungi such as Ascochyta. Thrips are difficult to control since they often migrate into peas from surrounding vegetable crops and weeds.
What to do:
Conserve natural enemies. Anthocorid bugs and predatory mites are important natural enemies of thrips. Avoid use of of broad-spectrum pesticides that kill natural enemies
Black, L.L.,Green, S.K., Hartman, G.L., and Poulos, J.M. (1991). Pepper Diseases: A Field Guide. Asian Vegetable Research and Development Center, Taipei. ISBN: 92-9058-048-8.
East African Seed Co. Ltd. Africa’s Best Grower’s Guide www.easeed.com
HCDA (1996). Chillies . Horticultural Crops Development Authority. Export Crop Bulletin: No 10, June 1996. Excerpted from the KEDS-Supported HCDA Export Crop Manual.
Hill, D. S. (1983). Agricultural Insect pests of the tropics and their control. Second Edition. Cambridge University Press. pp 76. ISBN: 0 521 24638 5.
Nutrition Data www.nutritiondata.com.
Pepper organic cultivation guide, Naturland 2001. Available also online www.naturland.de/en
Sherf, A.F., Macnab, A.A.(1986). Vegetable Diseases and Their Control. 2nd. Edition. John Wiley & Sons Inc. USA. ISBN: 0-471-05860-2
