Pacific Pests, Pathogens & Weeds - Mini Fact Sheet Edition

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Citrus scab (048)

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Photo 1. Light brown raised spots on twisted torn leaves of rough lemon, caused the citrus scab fungus, Elsinoë fawcettii. Note stems are also infected.

Photo 2. Small corky scabs on the fruit of rough (or bush) lemon, caused by citrus scab, Elsinoë fawcettii.

Summary

• Worldwide distribution. On lemon, rough lemon and mandarin. Other species of citrus - grapefruit, orange and pomelo - are also susceptible, but less so. An important disease.
• The fungus distorts the leaves and makes the fruit unsightly. It stunts common rootstocks in the nursery, so they are difficult to bud.
• Similar to citrus canker (see Fact Sheet no. 091), except leaves are stunted, wrinkled with torn margins.
• Spread is by wind and rain, by insects, on nursery plants, and fruits.
• Cultural control: make nurseries at distance from production areas; prune to keep open canopy, and improve air circulation.
• Chemical: in the nursery, use copper or chlorothalonil at the beginning of leaf flushes.

Common Name

Common citrus scab

Scientific Name

Elsinoë fawcettii. The fungus has an asexual stage, Sphaceloma fawcettii; this is the stage that occurs throughout the Pacific. There are strains of Sphaceloma fawcettii present elsewhere.

This mini fact sheet is a part of the app Pacific Pests, Pathogens & Weeds

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