Alternaria Brown Spot of Citrus Plants:

Caused by fungi Alternaria Citr.

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Symptoms:

• Symptoms on leaves are in the form of abnormal discolored rots and sometimes these appear on the fruit in the form of small and circular spots.
• With severe affliction, the rots expands to the veins on the leaves.
• Disease symptoms on the fruit appear immediately after the affection of the leaves and the initiating symptoms appear in the form of small black spots. Fruit affection appears as soon as flower petals drop.
• Symptoms on larger fruits take the form of external peel canker and such fruits do not fall.

Disease Cycle:

• Infection of new twigs has rarely bad effect on the growth of trees but the infection of early twigs assist in the increase of enough fungi pollen to infect the fruits.
• Fungal infection occurs largely on new affected twigs as compared to affected fruits.

Prevention:

• Moderation in the use of nitrogen fertilization and irrigation water quantity.
• Using copper compounds to combat this disease such as Superplus.