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March 30, 2018 - Sweet Orange Scab (SOS) (Elsinoё australis) was recently detected from citrus samples submitted to the Auburn Plant Diagnostic Lab for a citrus disease screen from Fairhope. This is a federally regulated pathogen. SOS was first detected in Alabama October 2017 from a residence in Lillian on a single citrus tree. The disease was found scattered throughout the planting in Fairhope. Lillian and Fairhope are on opposite sides of Baldwin Co. We suspect the pathogen was spread from Florida via hurricane movement in 2017. The pathogen may be widespread, but undetected at this time.

Foliage is not heavily damaged by SOS. The symptoms on leaves are very inconspicuous. However, symptoms on fruit are very distinctive. SOS can be a significant problem on fruit produced for fresh market and will have quarantine implications.

sos foliage 2.jpg

SOS fruit 2017.JPGFungicides can be used if timed correctly, but only to protect fruit from infection. Products containing the active ingredients azoxystrobin, trifloxystrobin, pyraclostrobin, ferbam, and copper fungicides can be used. These fungicides create a barrier on the fruit during its most susceptible growing period, reducing the amount of inoculum for infection. Two fungicide applications should be made: one at 2/3rd petal fall and a second spray 2-3 weeks later.

Kassie Conner, Extension Specialist

 Plant Diagnostic Lab


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