GINGER (Step 9)

Pest and Disease Management

SHOOT BORER:

SYMPTOMS:

  • The most damaging insect pest to ginger is the shoot borer (Conogethes punctiferalis).
  • The larvae bore into the pseudostems and fed on the internal tissues, causing the leaves of infested pseudostems to turn yellow and dry.
  • A bore-hole on the pseudostem through which frass extruded, as well as a withered and yellow central shoot, are both signs of pest infestation.

CONTROL:

  • During the months of July to October, apply malathion (1ml/lit) at 21-day intervals to control the shoot borer.
  • When the first signs of pest attack appear on the topmost leaf in the form of feeding scars on the pseudostem's edges, spraying should begin.
  • An integrated strategy combining pruning and killing newly affected pseudostems at fortnight intervals during July-August and spraying malathion (1ml/lit) at monthly intervals during September-October is also effective against the pest.

RHIZOME SCALES:

SYMPTOMS:

  • Rhizomes in the field (at later stages) and in storage are infested by the rhizome scale (Aspidiella hartii).
  • They feed on sap, and when the rhizomes are heavily affected, they become shrivelled and dried, inhibiting germination.

CONTROL:

  • The rhizome scale can be controlled by harvesting the seed rhizomes on time, eliminating severely contaminated rhizomes, and treating the seed rhizomes with Quinalphos @0.75ml/lit for 20-30 minutes before storage and sowing if the infestation persists.
  • After seed treatment, the seed rhizome can be stored in a mixture of sawdust and dried Strychnos nuxvomica leaves.

LEAF ROLLER:

SYMPTOMS:

  • Leaf roller larvae (Udaspes folus) cut and fold leaves while feeding from within.
  • They are most commonly seen during the monsoon season.

CONTROL:

  • The control measures taken against the shoot borer malathion @1ml/lit spraying are sufficient for the pest's management.

DISEASES OF GINGER:

RHIZOME ROT /SOFT ROT:

SYMPTOMS:

  • The infection begins at the pseudostem's collar and spreads upwards and downwards. The damaged pseudostem's collar gets waterlogged, and the rotting spreads to the rhizome, resulting in soft rot with a distinct odour.
  • Root infection is identified later in the process. Light yellowing of the lower leaf edges appears first, then spreads to the leaf lamina.
  • The middle half of the leaves remains green while the edges turn yellow in the early stages of the disease.
  • Drooping, withering, and drying of pseudostems occur as the yellowing extends to all of the plant's leaves from the lower to upper regions.

CONTROL:

  • Seed rhizomes were treated for 30 minutes with mancozeb 3g/lit or Metalaxyl Mancozeb 1.25g/lit before being stored.
  • The use of Trichoderma harzianum in combination with neem cake (1 kg/bed) helps to reduce the disease's occurrence.
  • Once the disease has been identified in the field, it is controlled by removing affected clumps and soaking the affected and adjacent beds with Mancozeb 3g/lit, Metalaxyl Mancozeb 1.25g/lit, or Copper oxychloride 2g/lit.

BACTERIAL WILT:

SYMPTOMS:

  • Ralstonia solanacearum Biovar-3 causes bacterial wilt, which is a soil and seedborne disease that occurs during the south west monsoon.
  • Water-soaked patches emerge near the pseudostem's collar and move upwards and downwards.
  • Mild drooping and curling of lower leaf edges that spread upwards is the first noticeable symptom.
  • The plants show severe yellowing and withering symptoms at the advanced stage. Dark streaks can be seen in the vascular tissues of the affected pseudostems.
  • When gently pressed, the affected pseudostem and rhizome extrudes milky ooze from the vascular strands. Rhizomes eventually decay and emit a bad odour.

CONTROL:

  • When the disease is discovered in the field, the infected clumps should be carefully removed without losing soil, and the affected area and nearby areas should be drenched with copper oxychloride @2g/lit
  • It is recommended that the removed plants be disposed of far away from the agricultural area or burned.

LEAF SPOT:

SYMPTOMS:

  • Phyllosticta zingiberi causes leaf spot.
  • The disease begins as a wet spot and develops to a white area with dark brown edges and a yellow halo.
  • The lesions grow larger, and neighbouring lesions join together to form necrotic patches. During sporadic rains, the disease is spread via rain splashes.

CONTROL:

  • With the appearance of disease symptoms, spraying of Bordeaux mixture @ 10g/lit, mancozeb@ 2g/lit, or carbendazim @2g/lit can be used to control the disease.
  • It is important to ensure that the spray solution reaches the lower surface of the leaves as well.
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