Insect Pests of Fruit, Plantation, Medicinal & Aromatic Crops (2+1)

4. Eriophyid mite

4. Eriophyid mite - Aceria gurreronis Keifer. (Eriophyidae: Acarina)

Damage

• The mite infests and develops on the meristematic tissues of the growing nuts under the perianth by desapping the soft tissues of the buttons.
  
• In the damaged buttons / nuts, an initial symptom will be exhibited in the form of triangular pale white or yellow patches close to each perianth.
  
• Different stages of mite live in white, tender portion covered by the inner tracts of the perianth and suck the sap continuously when the feeding activity is enhanced due to the increased population build up it results in physical damage to newly formed tissues which become necrotic.
  
• Intensive damage leads to the formation of brown coloured patches later on.
  
• In addition as the nut grows in size, longitudinal fissures and splits occur on the outer surface of the husk.
  
• Occasionally brownish gummy exudates are seen oozing out from the affected surface.
  
• Severe infestation results in poor growth reduced size and copra content and malformed nuts with cracks and hardened husk.



Bionomics

• It is found under the tracts of fertilized female flowers.
  
• It is very minute in size measuring 200-250 micron in length and 36-52 micron in width with two pairs of legs.
  
• It is pale in colour with elongate body and worm like in appearance.
  
• The life cycle of this mite consist of egg, two larval instars and one adult stage is completed in 10-12 days.



Management

• Apply urea 1.3 kg, super phosphate 2.0 and muriate of potash 3.5 kg/palm/year (Increased quantity of potash is recommended to increase the plan! resistant to the mite).
• Apply neem cake @ 5 kg and organic manure @ 50 kg / palm / year.
• Apply borax 50 g + gypsum 1.0 kg + manganese sulphate 0.5 kg / palm.