Tropical and subtropical fruits (2+1)

Physiological Disorders

Fruit drop

• Mandarins also drops the flowers and fruits at different stages adjusting to its resources.
• But preharvest fruit drop reduces the yield.
• It can be controlled by proper cultural management and treating with 2, 4-D (10ppm) or NAA (5ppm) or 2, 4, 5-T (5ppm) and Aureofungin 20 ppm to check any fungal diseases.
Granulation

• A physiological disorder causing drying up, becoming hard with grayish color and enlargement of the juice vesicles with increase in pectin, lignin, etc. resulting in reduction of the juice content.
• This occurs more in young vigorous trees than old trees.
• It can be reduced by spraying lime, reducing irrigations and application of 2, 4-D (12ppm) or Znso4 + Cuso4 mixture (0.5 %).
Decline: Decline occurs in mandarin also.