Growing String Beans or Sitaw with Cost Analysis

Variety Description  (Fresh)

a. Sandigan  (UPLPS-1)

  • yield: 13.3 tons/hectare (t/ha) wet season (WS); 24.2 t/ha dry season (DS)
  • harvest maturity: 50 days (WS); 49 days (DS)

b. Ana (UPLPS-2 or CSL19)

  • yield: 7.1 tons/ha (WS); 12.6 tons/ha (DS)
  • harvest maturity: 43 days (WS); 37 days (DS)

Both varieties:

  • pods are light green, crisp, good-textured, non-fibrous
  • pod length: 56.2 cm, pod width: 0.7 cm
  • moderately resistant to black bean aphids and beanfly
  • NSIC-released variety

Environmental Requirements

  • Grows well under lowland tropics with temperature ranging from 20°C to 35°C
  • Thrives well in both low and high areas
  • Can be grown in many kinds of soil and is more tolerant to acid soils than mungbean and soybean
  • Susceptible to waterlogging and drought which reduce yield considerably
  • Seed production is best during dry season to avoid rotting of pods and germination of seeds while in the pod
  • Choose an area which has not been planted to other varieties of pole sitaw for two seasons to avoid contamination of seeds from the previous crop

Cultural Management

a. Land Preparation

  • Prepare land thoroughly by mechanical means or with the use of animal drawn implements.
  • Make sure to breakdown big clods.
  • Space the furrows 75 cm apart.

b. Planting

  • Pole sitaw is usually direct seeded but can be transplanted. It requires 10-12 kg seed per hectare.
  • In the field with 0.75 m furrow rows, plant the first two rows leaving the third row vacant and again on the next two rows, leaving the next row unplanted. This is to provide space to perform other field operations more efficiently within the trellis. If furrows are 1 m wide, plant every row.
  • Plant 2-3 seeds per hill spaced 30 cm apart and cover lightly with soil.
  • 2-3 weeks after planting, thin out weak and diseased seedlings leaving behind one healthy plant per hill.

c. Fertilization

  • The rate of fertilization depends on soil analysis, but in its absence, apply 10 gm or 1 tbsp complete fertilizer (14-14-14) per hill before planting and cover with soil. Add a handful or two of well decomposed manure
  • At early vegetative stage or a month after sowing, sidedress about 15 g of a mixture of 2 parts Urea (46-0-0) and 1 part Muriate of Potash (0-0-60).
  • Use rhizobium inoculants to reduce fertilizer rate. The inoculant is mixed with the seed prior to planting.

d. Irrigation

  • Irrigate immediately after planting to ensure uniform seed germination.
  • During the dry months, furrow irrigate every 10 days. Irrigate only when necessary during wet season. Construct drainage canals at the end of rows to avoid flooding.

e. Weeding

  • Hand-weed thoroughly the planted rows.
  • Underbrush or rotavate the large spacing in between rows.

f. Trellising

  • Lay-out 2.5 m long and 2-2.5 m diameter poles. 4-5 m apart along the planted rows.
  • Connect the poles at the top along the rows with wire (#16) and tie the top wire to a posted stake at the end of the row to make the poles stable.
  • Connect the poles along the rows in the middle and lower portion of the poles with wire.
  • Cut abaca twine or synthetic twisted twine and tie them vertically from the top to the bottom wires in every hill. Intertwine the vine in a counterclockwise manner to the vertical strings.

g. Insect Pest Management

  • Beanfly (Ophiomyia phaseoli Tyron). – adult is a minute jet black fly that lays its eggs on the cotyledonary leaves, manifested by whitish dots. When the eggs are hatched, the reddish-to-yellow maggots feed as miners working down the petiole into the stem. Severe infestation results in wilting and drying up of stems and leaves. Control: spray systemic pesticides
  • Bean pyralid or beanfly borer (Maruca testulalis Geyer) – the adult moth has dark fuscus brown anterior wings with large regularly bordered hyaline across the middle of the two small sub-basal hyaline spots. The eggs are laid singly or in groups, scattered on petals and sepals. The larvae are voracious feeders of inflorescence resulting in pod deformities or underdeveloped pods. Control: spray systemic pesticides
  • Blackcutworm (Agrostis ipsilon) – eggs are laid on stems of grasses and weeds or behind the leaf sheath of the host plant; others are laid on low spots in the field; or land that has been subjected to overflow. The larvae remain buried 1-2 inches below the surface of the ground. The degree of damage is high within the first week after germination. Control: apply chemical granules on soil at seedling emergence.
  • Leafhopper (Empoasca spp.) – the adult leafhopper is yellowish green and has a prominent small black spot on each forewing. It usually hides under leaf surface causing leaf curling. Control: spray appropriate insecticides When spraying, apply on the underside of the leaves
  • Aphids (Aphis craccivora Kock) – these are minute, black insects, mostly wingless, sucking plant juices on pod and young shoots resulting in yellowing, stunting, and deformations on the plant. They harm the crop by sucking the sap and transmit virus to the plant. They usually attack at seedling to early vegetative stages. Control: spray appropriate insecticides
  • Leafminer (Stomopteryx subsecivella Zeller) – eggs are laid on the leaves and hatch into reddish caterpillars (Microlepidoptera). The caterpillars mine their way inside the leaves by feeding on parenchyma cells. As a result of feeding, only the silvery membrane of the leaves remain, making the larvae visible externally. Heavy infestation cause premature defoliation. Control: spray appropriate insecticides

h. Disease Management

  • Cowpea rest or brown rust (Uromyces appendiculatus) – the
    disease starts as whitish raised pustules turning brown with powdery uridiniospores. The entire leaf can be covered with pustureles and dry up. Older leaves are more susceptible than the young ones. Prevention: sanitation, crop rotation, and use of resistant varieties. Control: spray fungicides.
  • Bean mosaic – infected leaves are usually irregularly shaped with light green areas of various sizes. The disease is caused by virus, with aphids or plant lice as carriers. Prevention: remove infected plants to prevent contamination and use uninfected seeds.
  • Anthracnose caused by Colletotricum lindemuthianum and Powdery mildew caused by Oidium sp. Control by spraying fungicides at weekly intervals. Plant only seeds from disease-free plants.

i. Pollination/Isolation

  • Highly self-pollinated although cross-pollination occurs
  • Observe an isolation distance or planting one variety away from another variety at a distance of 20 m for certified seed and 30-50 m for breeder seeds.
  • Flowers open early in the morning and never close. Anthers dehisce the night before flower opens.

j. Roguing

  • Remove off-types, diseased, and virus-infected plants
  • Conduct field inspection at early vegetative stage, flowering stage, and fruiting stage.
  • At vegetative stage, check the shape and color of the leaves, and foliage cover. Also, check the color and size of stem, and internode length.
  • At flowering stage, observe for the date of flowering, height of first flower, and color of the flower
  • At fruiting stage, observe for the color and length of pod, and the length of pod stalk.

k. Harvesting

  • Harvest pods when physiologically mature or when pods have turned leathery brown.
  • Harvest three times a week at peak harvest.

Postharvest Handling
a. Seed Processing

  • Dry pods under the sun 2-3 days or until brittle
  • Put dried pods in net bag and beat manually with stick, or by rubbing and splitting by hand in the absence of threshing machine.
  • Remove trash by winnowing or by passing through an air screen cleaner.
  • Sort out small and wrinkled seeds and seeds with holes.
  • Dry under the sun for 4-5 days or until moisture content is 11% or less.

b. Packaging/Storage

  • For home use, pack seeds in a thick plastic or paper envelopes, and place in large aluminum cans or large-mouth jars lined with charcoal, lime, or silica gel at the bottom.
  • Seal well.  Place in a cool, dry place.
  • For large volume seeds, pack seeds in thick plastics or aluminum foil and seal well.
  • Keep in a cool and dry place or storage area. The drier the stored seeds and cooler the storage area, the longer the life of the seeds.

Cost and Return Analysis (2008 data)

For more information, contact:

Crop Science Cluster-Institute of Plant Breeding
College of Agriculture, UP Los Banos College, Laguna
Tel. Nos.: (049) 536-5287; 576-0090

PCARRD, Los Banos, Laguna
Tel. Nos.:   (049) 536-0014 to 20; 536-5907
E-mail:      [email protected]
Website:    www.

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