Plantation Crops (2+1)

Physiological disorders arecanut

1.Band or hidimundige disease
• Band = barren (in marathi).
• This disease is a major problem in Konkan Coast of Maharastra. Diseased palms ceases to produce fruits.
• It is known as hidimundige disease in Karnataka
  

  In Sri Lanka = Pencil point disease and
  In Austrelia = Rosette disease

Symptoms
• Production of smaller leaves and ultimately crown forms a rosette shape
• Reduction in internodal length and tapering of stem towards apex
• Mostly unproductive :nuts if at all produced are small and malformed.

Etiology
• Poor drainage and low fertility of soil
• Sub soil pan / hard clayey pan

Control
• Better soil management and improvement in drainage.
• Removal of hard pan on the sub soil and foliar application of micronutrients,
• Correction of soil acidity and incorporation of mixture of copper sulphate and lime.

2.Nut splitting in arecanut
• A physiological disorder of universal occurrence in almost all gardens. It is purely physiological.
• The growth of pericarp does not keep pace with the development of kernel inside and thus causing the splitting up of the pericarp and distal end. The split nuts drop. Infection of bacteria and fungus of the exposed kernel after splitting renders the nuts useless.

Symptoms
• Premature yellowing of nuts when they are ½ to ¾ matured. It is seen in patches in individual plantations and common on young palms.

Cause/ Reasons
• Excessive flow of cell sap into the inflorescence in very healthy palms.
  

  o Excessive flow of sap in to the inflorescence
  o Excessive nutrient supply
  o Prolonged drought followed by sudden irrigation
1. Application of borax @ 2 g per liter of water (0.20 % spray) on bunches during early stages of disease. and K2O at the base is found to check nut splitting to a certain extent.
2. Improvement of drainage and provide regular irrigation during drought

3.Sunscorch and stem breaking

Symptoms
• Stem: Golden yellow spots which later turn brown. In advanced stages fissures develop at these points. Further, saprophytic micro organisms and insects harbour in these portions leading to breaking of stem at later stages.

Cause
• Due to adverse effect of solar radiation., i.e., palms exposed to the south western sun are affected.