Florida's lucrative avocado industry could face a serious blow from a duo of deadly new invaders. Together, the invasive fungus called "laurel wilt disease" and the redbay ambrosia beetle, which carries laurel wilt, represent a significant economic threat to the industry. According to a report published in HortTechnology, direct losses from the invasion could range from $183 million to a remarkable high of $356 million. "The impact on the local economy would be catastrophic", noted Dr. Edward A. Evans of the University of Florida's Tropical Research and Education Center, one of the authors of the study.
Avocados are Florida's second-largest fruit industry (after citrus). The industry brings in substantial revenue to the state, resulting in an overall economic impact of about $54 million a year. More than 98% of 7,400 acres of commercial avocado orchards are located in southwestern Miami-Dade County. Most growers depend on proceeds from the sale of avocado to supplement their income, while many packing houses depend almost exclusively on the crop to sustain their operations. Avocado orchards also offer a variety of nonfood benefits, including the retention of open space, landscaping, well-field recharge, and wildlife habitats.
In 2002, the redbay ambrosia beetle, along with its fungal symbiont, the laurel wilt pathogen, was introduced in Georgia on contaminated wood packing material. In 2005, humans spread the pest into northern Florida, and by 2007, laurel wilt had invaded central Florida, where the first avocado tree known to succumb to the pest was identified in Jacksonville. There are currently no registered fungicides that control laurel wilt in avocado. While chemical and/or biological control of the disease might be a possibility, little research currently exists that indicates methods for implementing disease prevention.
The scientists investigating the regional impacts of laurel wilt emphasized the critical need for quick action to address this rapidly moving disease. "The results of our investigation indicate that the direct loss to the industry in terms of lost sales, property damage, and increased management costs could range from $356 million in a do-nothing situation to about $183 million if damage control measure were 50% effective", stated Dr. Jonathan Crane, who headed the research effort. Crane added that this estimate could be considered conservative, since the study did not include the economic impact on noncommercial production, residential infestations, avocado or forest trees, scenic beauty, wildlife, or the loss of canopy cover.
The report concluded with recommendations to implement policies and ramp up research efforts aimed at decelerating the spread of the disease and developing effective treatments to preserve the important Florida avocado industry.
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More information: The complete study and abstract are available on the ASHS HortTechnology electronic journal web site: horttech.ashspublications.org/cgi/content/abstract/20/1/234
