“SOS doesn’t affect the fruit itself or taste but it does affect the marketability of the fruit,” said Tess Williams, trade specialist with APHIS-PPQ in Phoenix.

Australia has banned the importation of Arizona citrus due to SOS, says Williams. APHIS is working to reopen the market for the 2011-2012 Arizona citrus shipping season.

About 80 percent of Arizona citrus is grown in Yuma County (mostly lemons), says Glenn Wright, University of Arizona citrus specialist. The balance is grown in Maricopa and Pinal counties. Statewide, citrus acreage totals about 17,300 acres. About one-third of the crop is exported; mostly to Japan, Canada, South Korea, and Hong Kong.

SOS was first confirmed in the United States in July 2010 in Springs, Texas near Houston on residential lemon and tangerine trees. APHIS enacted a federal quarantine in Texas and Louisiana after additional finds. Arizona and Florida are next in line.

“The only state left that hasn’t detected SOS in the continental U.S. is California,” Levitt said. “They are out looking for it.”

SOS is expected to be a smaller threat in Arizona compared to the ACP insect first found in Arizona in late 2009. The ACP is the primary carrier of HLB which has devastated Florida’s citrus industry. Every tree infected with HLB eventually dies. The fruit becomes sour and unmarketable. The pest-disease combo has impacted global citrus production.

SOS requires high levels of humidity and rain to thrive.

“The Arizona environment is not very conducive to a rampant spread of SOS,” said John Caravetta, ADA associate director and head of the plant services division. “That’s why it appears to be well managed through cultural practices.”

Suggested cultural practices include clean orchard floors and approved fungicides for SOS and citrus scab.

“Keeping the orchard floor clean is part of the process to keep from generating inoculum from infected fruit that will sporulate with the fungus,” Caravetta explained.

Citrus from quarantined Arizona will be allowed to move interstate to all states with a certificate if washed, brushed, and the fruit surface is disinfected with one of three APHIS-approved chemical treatments.

Brothers Mark and Bill Spencer are fourth generation citrus growers; each with 30 years experience in production and packing. Mark says existing company packinghouse procedures already meet most of the APHIS requirements. Tweaking at the wash line will include increased chlorine use to 200 parts per million and fungicide use during the entire packing season.

The company exports 25 percent of the fruit. Exports account for about 35 percent of the FOB sales. Japan is Associated Citrus Packers’ largest export destination followed by Australia. It takes about 21 days to ship lemons from Yuma to Australia.