Alternaria Brown Spot of Citrus

Symptoms

Brown-to-black necrotic spots with yellow halos on young leaves, twigs, and fruit, sometimes causing dieback of affected shoots.

Favorable conditions

• •Wet, mild spring weather during new growth flushes
• •Highly susceptible tangerine and tangerine-hybrid cultivars

Management

1. 1Time copper or strobilurin fungicide sprays to new growth flushes
2. 2Plant less-susceptible varieties where possible
3. 3Avoid excess nitrogen that promotes vulnerable new flush growth