By Kyle LoJacono
An incurable disease has spread to 33 of Florida’s citrus-producing counties and threatens the long-term health of the industry in the Sunshine State.
It is called the huanglongbing (HLB), but is also known as yellow dragon disease or citrus greening. The disease was first recorded in the Tampa Bay area in 2007. There have been more than 1,900 confirmed cases of HLB in Florida as of the end of 2009, with at least 36 in Pasco and Hillsborough counties combined. The only citrus-producing counties not affected are in north Florida.
“It is the most serious citrus disease out there,” said Florida Citrus Mutual spokesman Andrew Meadows.
While all citrus plants are vulnerable to HLB, sweet and mandarin oranges are the most affected. Sour oranges, grapefruits and lemons are only moderately susceptible, as are plants related to citrus such as the limeberry.
George Neukom III, of Zephyrhills, runs one commercial grove in Pasco and is on the board of directors for the mutual.
“We’re just starting to see the shirking of the fruit and the other symptoms of the greening,” Neukom said. “We expect to see more next year…I’m very fearful of it. I’ve seen groves down south that have had the disease longer and it can get very bad.”
Neukom has had to remove 10 to 15 trees this year because of HLB. The disease plus the extreme cold from last winter could have destroyed the next crop, but his grove has been able to dodge both bullets to this point.
“We would have lost some of the smaller trees if we hadn’t used the water to protect them,” Neukom said. “We were really lucky because it was cold enough to do a lot of damage…Our next crop will be ready in November and I expect it to be a good one as long as we don’t see problems with the disease.”
HLB causes leaves to develop yellow blotches, poor flowering and stunted tree growth according to Florida Citrus Mutual. Fruit from infected trees are usually misshapen or shrunken, remain green when ripe and taste either bitter or very sour.
Trees may not exhibit symptoms for six to 18 months and by that time much of the grove is usually infected. Citrus plants generally die within two years of contracting HLB.
The disease was first detected in the United States in September 2005 in Dade and Broward counties. HLB is spread by two species of psyllid, a flying insect. Only the Asian variety has been seen in this country.
Psyllids carry the bacterium that causes the greening and pass it to the trees while feeding on the sap. HLB is not spread by wind, rain or contact with contaminated tools.
While HLB poses no threat to people, animals or plants that are not related to citrus, the disease is a risk to the $9.3 billion citrus industry. There are no projections of how much HLB will hurt the industry this year.
The best way to prevent the spread today is to remove infected trees from a grove as soon as it starts to display symptoms. Generally trees near the infected ones are also removed in case they have caught the greening.
In addition, the Florida Department of Citrus is researching more effective pesticides to reduce the number of psyllids and developing strains of citrus that are resistant to HLB.
A smaller grove in Zephyrhills is the one owned by Charlie Proctor. He has grown all naval oranges on the land for seven or eight years.
“I haven’t had problems with that yet,” Proctor said of HLB. “I have a guy who takes care of the grove for me and he hasn’t said anything about it getting to the trees.
“Last year was the first time I lost money on the grove, but that was because we didn’t get enough water until too late in the season so we only got a few oranges,” Proctor continued. “It wasn’t because of the greening.”
The Florida Department of Agriculture is encouraging anyone who has a tree infected with HLB to remove it as soon as possible to prevent the spread of the disease. For more information on HLB, visit the mutual’s Web site, www.flcitrusmutual.com.