New citrus disease on the move

The USDA-Animal and Plant Health Inspection Service (APHIS) Molecular Diagnostics Laboratory has confirmed eight sets of Citrus spp. fruit collected in residential areas in Pearl River, Hancock, and Harrison Counties in Mississippi to be positive for the fungal pathogen, Elsinoë australis, causal agent of sweet orange scab (SOS). The lab received the samples in late October.

Sweet orange scab is a fungal pathogen of citrus that results in unsightly, scab-like lesions developing on fruit rinds and, less often, on leaves and twigs. The damage produced is superficial and does not affect internal fruit quality or taste. Infected fruit are more likely to drop prematurely, and the scabby lesions reduce the fruit’s fresh market value. In addition, the disease may stunt young citrus seedlings. The disease has been found in South America (Argentina, Bolivia, Brazil, Ecuador, Paraguay, and Uruguay) and in Oceania (Cook Islands, Fiji, Niue, and Samoa).

APHIS is coordinating with the Mississippi Department of Agriculture to determine the source and the extent of the infestation.

In late July, APHIS confirmed the identification of SOS on residential lemon and tangerine trees in Harris County, TX. This was the first confirmation of SOS in the U.S. Currently, 11 counties in Texas have been confirmed with the fungal disease. In late August, APHIS also confirmed the presence of SOS in Orleans Parish, LA. The detection was located on a single residential lime tree.

Subsequent detection survey activities have resulted in 14 additional parishes confirmed positive for the fungal pathogen.

Source: North American Plant Protection Organization’s Phytosanitary Alert System