Citrus Tristeza

TristezaChlorotic leaf flecking, vein clearing, leaf cupping, corking of leaf veins, and stem pitting.

Serrano, D., Serrano, E., Dewdney, M., and Southwick, C. (2010). Citrus Diseases. USDA/APHIS/PPQ Center for Plant Health Science and Technology. [09-14]

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Sweet Orange Scab

Sweet-orange-scabSweet orange scab does not usually form lesions on leaves or twigs in contrast to the more common Citrus scab.

Fruit- the rinds of young fruit display relatively large flat or warty outgrowths (windscar) which vary in color from a light pink to a grayish-brown with age. Sweet orange scablesions are flatter than those produced by E. fawcettii (Citrus scab).

Serrano, D., Serrano, E., Dewdney, M., and Southwick, C. (2010). Citrus Diseases. USDA/APHIS/PPQ Center for Plant Health Science and Technology. [09-14]

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Citrus Psorosis

PsorosisFoliar symptoms have a wide range and are best seen on young leaves nearing full expansion. Symptoms include chlorotic flecks that are irregularly distributed, leaf mottling, and round chlorotic spots. Symptoms may fade as leaves mature.

Serrano, D., Serrano, E., Dewdney, M., and Southwick, C. (2010). Citrus Diseases. USDA/APHIS/PPQ Center for Plant Health Science and Technology. [09-14]

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Citrus Pseudocercospora

PseudocercosporaThe fungus produces circular, mostly solitary spots up to 10 mm in diameter, which often coalesce. Lesions have light brown or grayish centers when dormant and are non-sporulating during the dry season, but becoming black with sporulation after the onset of the rainy season. The lesions are usually surrounded by a dark brown margin and a prominent yellow halo; occasionally the centre of the lesions falls out, creating a shot-hole effect. At first glance the young lesions appear similar to those of canker (caused by Xanthomonas citri spp.-pv citri) but differ in being flat or shrunken. Leaf spots, especially on younger leaves, often coalesce and cause generalized chlorosis, followed by premature abscission and defoliation of the affected tree. Yound leaves and fruit appear to be more susceptible than older mature leaves, but whether the leaves or fruit are more affected varies with the hose species, variety, and location.

Serrano, D., Serrano, E., Dewdney, M., and Southwick, C. (2010). Citrus Diseases. USDA/APHIS/PPQ Center for Plant Health Science and Technology. [09-14]

Read more ...