Canker

Canker:- 

Pathogen:- Xanthomonas campestris pv citri

Symptoms:-

i. Acid lime, lemon and grapefruit are affected. Rare on sweet oranges and mandarins.

ii. Affects leaf, twig and fruits. In canker, leaves are not distorted.

iii. Lesions are typically circular with yellow halo; appear on both sides of leaf, severe in acid lime (difference from scab) When lesions are produced on twigs, they are girdled and die.

iv. On fruits, canker lesions reduce market value.

Management:-

i. Streptomycin sulphate 500-1000 ppm; or Phytomycin 2500 ppm or Copper oxychloride 0.2% at fortnight intervals.

i. Control leaf miner when young flush is produced.

iii. Prune badly infected twigs before the onset of monsoon