DISEASES & PESTS

DISEASES & PESTS

Damping off: (Pythium spp. and Rhizoctonia solani)
  • Affected seedlings collapse at the ground level and die.
  • Affected roots are usually discoloured and often become reddish brown.
  • Excessive moisture is favourable for damping off disease.
Control measures:
  • Provide good drainage, treat the seed with ceresan (2g/kg seed), avoid overcrowding of the seedlings, thin out seedlings which are large enough to handle and remove all affected seedlings and destroy them.
Sclerotium root rot: (Sclerotium rolfsii)
  • Affected leaves become yellow and wilt.
  • The roots start to decay.
  • Presence of strands of fungal mycelium and brown sclerotia on the decaying roots is often seen.
Control measures:
  • Collect the crop residue and destroy it.
  • Uproot the affected plants and destroy them.
  • Drench the plants with carbendazim (0.1%) around the roots.
Downy mildew: (Peronospora schachtii)
  • It may occur at any stage of growth.
  • All above grounds parts may be affected.
  • On the leaves, spots of different sizes up to 4 cm in diameter appear.
  • The affected portions become light green on the upper surface, while on the under surface the mildew (fungal growth) is noticed.
  • The infected leaves may become small and thicker than normal, and are often curled downward at the edges.
Control measures:
  • Control measures include field sanitation, crop rotation, use of resistant cultivars and seed treatment with fungicides.
  • Spray with 0.3 percent Zineb thrice at an interval of 15 days is also an effective control measures.
BACTERIAL DISEASES
Bacterial blight: (Pseudomonas syringae pv. aptata)
  • Leaves show circular to irregular leaf spots, which have a tan center with a dark margin.
  • Disease also shows symptoms on leaf edges.
  • These spots later coalesce causing the leaves to have a ragged appearance.
Control measures:
  • Follow proper sanitation and crop rotation.
VIRAL DISEASES
Beet yellowing virus:
  • It is sometimes serious.
  • It is a viral disease and transmitted by aphids.
  • Conspicuous mottling with chlorotic zonate ring spots are common symptoms.
  • These may become necrotic with age.
  • Virus infected plants remain stunted and may loose some leaves.
Control measures:
  • Follow proper crop rotation and sanitation practices.
  • Isolate the healthy plants which may act as secondary hosts.
  • Control the insects and destruction of infected plants also prevent the spread of the disease.
PESTS
Beet leaf miner: (Pegomyia sp.)
  • It makes tunnels inside the leaves.
  • The larva feeds on the tissues between the upper and the lower layer of leaf, thus causing serious injury to the leaves making it unfit for manufacture of food, consequently the plant growth is checked.
Control measures:
  • Destroy all fallen leaves and other plants refuse after harvesting of roots.
  • Spray systemic insecticides like oxy-demeton methyl (0.025%) on underside of leaves.
Beet web worm: (Hymenia sp., Loxostege sp.)
  • The caterpillar sometimes causes very serious damage.
  • The adults lay eggs on the leaves and the larvae attack the foliage, either by spinning small webs among the tender leaves or feeding on the underside, protected by small webs.
Control measures:
  • Manage the insect by spraying malathion (0.05%).
Physiological Disorders:
Heart rot or Crown rot
  • The disorder is caused by boron deficiency.
  • The leaves die in the crown which is covered with small deformed leaves.
  • The older leaves wilt and become necrotic.
  • The entire crown becomes necrotic and starts to decay.
  • The inner portion of affected roots turns black and become unfit for consumption.
Correction:
  • Soil application of borax (10-15 kg/ha) or foliar spray of boric acid (0.2%), 2-3 times at vegetative stage can check it.
  • Avoid the sowing of beet in acidic soils.
  • Avoid drought conditions by supplying reduced irrigation.
Speckled yellows
  • It is due to the deficiency of manganese.
  • The leaves of the affected plants show yellowish-green chloratic mottled areas which become necrotic resulting into breaking of lamina.
  • The leaf margins roll upward and turn into an arrow-shaped outline which remains upright.
Correction:
  • Apply manganese sulphate @ 5-10 kg/ha or foliar spray of manganese sulphate (0.2%) 2 to 3 times
  • Avoid planting on very sandy and alkaline soils.
SEED PRODUCTION
Methods of Seed Production
  • Both seed to seed and root to seed methods can be employed for raising seeds of beet root.
  • However, the usual method of production of beet seed is by root to seed method.
Root to seed method
First season
  • Raising of roots- as discussed for table crop
Time of Sowing
  • Unlike other crops, garden beet does not have any tropical type. Hence their seeds can only be produced in the hills of India.
  • Like carrot, beet requires exposure to low temperature of 4.4 -7.7oC for 6-8 weeks for initiation of flower stalks.
  • In hills, the best time is from mid July to the end of July.
  • Late varieties can be sown from last week of June to mid July.
Roguing
  • Before uprooting, the standing crop is examined for foliage according to varietal characteristics in the field.
  • All plants showing differences in leaf colours are discarded.
  • In variety ‘Crimson Globe’, the leaf character is marked by maroon shade over dark green background.
  • The plants having light background of light green foliage exhibit corresponding light colour of skin as well as of flesh with distinct zoning in certain cases.
  • In variety “Detroit Dark Red” the leaves are dark purple coloured.
Harvesting of Roots for Transplanting
  • After harvesting, each steckling is critically examined for foliage and root characteristics namely size, shape, colour, texture, sponginess etc.
  • For examining the interior, cut their 1/4th foliage and 1/3rd root portion.
  • Steckling having off type foliage or roots not conforming to varietal characteristics must be rejected.
  • The diseased, malformed, forked or any other undesirable types are also rejected.
Second Season
Preparation of selected roots for transplanting
  • After selection of tap root, the tops of the roots are trimmed taking care not to injure the crown and replanted in a well prepared field.
  • Planting of whole roots is advantageous.
Method of Transplanting
  • The trimmed roots as described earlier are reset in the field at a distance of 60 x 60 cm or 60 x 45 cm.
  • The soil is then firmed and tapped around the roots.
  • Soon after replanting, the field is irrigated.
Manures and Fertilizers
  • Apply 100-150quintals/ha of well rotten FYM at time of preparation of land.
  • At the time of final levelling, mix in the soil 50kg each of nitrogen and phosphorus and 100kg Potash per hectare as basal application and 50kg Nitrogen per hectare as top dressing during hoeing and earthing up stages.
Irrigation
  • First irrigation is given just after replanting. Irrigate the crop at 8-10 days intervals depending on the weather conditions.
Roguing
  • Seed stalk elongation in beet starts early in April, the first flower opens in May only.
  • The crop is in full bloom from mid May to mid June.
  • One roguing during this period should be done to remove early bolters, off type plants and diseased plants.
Flowering
  • The inflorescence, which normally develops in second year, is botanically a large spike.
  • The flowers are almost sessile; these arise in clusters of 3-4 in axils of bracts of the inflorescence axis and its secondary branches.
  • The flowers are small inconspicuous without corolla, but with green calyx which become thicker towards base as the fruit ripens.
  • Fruits are aggregate formed by the cohesion of two or more fruits and held together by swollen perianth (calyx) base and thus forming an irregular dry cork-like body, known as seed ball or so called seed, if there is a single flower, a single germ seed will develop.
Pollination
  • Beet root is highly cross pollinated crop.
  • Flower produce abundant small and light pollen grains which are carried by wind leading to wind pollination.
  • The whole face of flower bud development takes 35 days to become in bloom, there are 6 development stages through which bud passes before it opens into a flowers.
  • Anthesis takes place between 7 am to 5 pm with peak period between 11am to 1pm. The flower opens mostly during mid-day.
  • In the individual flowers, anthesis is completed within two hours and hastened by high temperature and low humidity.
  • Another dehiscence takes place between 8.30 am to 6.30 pm with peak period between 12.30 pm to 2.30 pm depending upon the temperature and humidity.
Isolation
  • Seed fields must be isolated from fields of other varieties and fields of same variety not confirming to varietal purity requirement of seed certification by five meters at mother root production stage and by 3000 meters for foundation seed production and 1000 meters for certified seed production.
Inspections
i) Mother root production stage
  • A minimum of two inspection shall be made as follows:
  • The first inspection should be done after 20-30days of sowing in order to determine isolation, off types and other relevant factors.
  • The second inspection should be done after the roots have been lifted to verify the true characteristics of roots
ii) Seed production stage
  • A minimum of two inspection shall be made as follows:
  • The first inspection should be done at pre-uprooting stage.
  • Other two inspections should be done one at uprooting and replanting stage and the final at pre-flowering stage in order to determine isolation and other relevant factors.
Seed Yield
  • Seed yield is 800-1000 kg/ha.
Last modified: Tuesday, 19 June 2012, 6:13 PM