FEATURE | c i t r u s
PROTECT YOUR HORSES FROM RABIES
Advances Against Greening
Fungal Pathogen Effective Control for Insect Associated With Citrus Greening by ROBIN KOESTOYO, UF/IFAS correspondent
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THE ASIAN CITRUS PSYLLID transmits the bacterium associated with the most serious citrus disease worldwide — and now it has a formidable enemy in a fungal pathogen. The disease is citrus greening — the citrus industry at its zenith was spread across about 950,000 Florida acres. Citrus greening reduced it to today’s approximate 400,000 acres. The fungus is Cordyceps javanica, strain Apopka, discovered by research scientist Lance Osborne in the mid-1980s. The fungus was isolated from dead insects on plants in a greenhouse at the University of Florida Mid-Florida Research and Education Center in Apopka. Spores of Cordyceps javanica spores grow in beadlike strands across citrus leaves, attaching themselves to the psyllid body, germinating, and infecting the psyllids, effectively lowering pest numbers by up to 90%. The fungus sustains itself and its impact on the psyllids for two full weeks after its application. Scientists at two UF Institute of Food and Agricultural Science (UF/ IFAS) research centers published their findings in the Sept. 14 issue of Insects, a peer-reviewed science journal. “Growers must control the psyllid to produce fresh fruit,” says Pasco Avery, a UF/IFAS Indian River Research and Education Center (IRREC) scientist in Fort Pierce. “What the growers need is an integrated pest management program to mitigate the psyllid populations, minimize the input of non-selective insecticides, and preserve
PASCO AVERY
the lady beetles, lacewings, and parasitic wasps that are the psyllid’s natural enemies.” The adult Asian citrus psyllid is attracted to volatiles that the citrus trees release while they are in “flush” or when new leaves on branches emerge. Psyllids land on the new citrus flush, and while feeding, insert the citrus greeningassociated bacterium into the tree’s phloem. Avery said the psyllid develops resistance to synthetic broad-spectrum chemical insecticides, and therefore, an integrative pest management program is requisite. Scientists can employ a combination of tools such as the fungus C. javanica, along with the psyllid’s natural enemies to protect the trees. CONTINUED ON PAGE 30
FloridaAgNews.com
RABIES IS A DEADLY VIRUS spread through the bite of an infected mammal such as a bat or other wildlife. Rabies infections will lead to death within a few days of symptoms being detected in an animal and pose a serious risk to you and your family. Although rabies infection in horses is uncommon, it does happen and is a very serious concern. There is no treatment for rabies, so prevention is the only way to keep you and your horses protected. Rabies vaccinations have been used in horses for years and are a safe and effective way to fight this dangerous disease. With Polk County receiving rabies alerts from the Florida Department of Health in July and August, the time is more important now than ever to get educated about rabies and ensure your horses are up-to-date on their vaccination status. Consult with your veterinarian for specific guidance regarding vaccination timelines and boosters for your horses. CONTRACTING RABIES. Rabies has been mostly eliminated in domestic animals in the United States, but can be hard to control due to wild animal exposure. Horses that live outside 24 hours a day are at a greater risk for rabies, but the disease is still fairly uncommon. It affects between 30 and 60 horses per year and is contracted by passing the rabies virus into an open wound or mucous membrane. At the time of publication, the recent rabies alerts for Polk County indicate two foxes and 1 bat have tested positive for the disease. SYMPTOMS. This disease in horses is not necessarily easy to diagnose, as the symptoms can be confusing and nonspecific. Typical symptoms can include colic, obscure lameness, paralysis, tremors, fever, depression and aggression, but could also appear as a lack of eating or drinking and teeth grinding. TREATMENT. Once infected, it is possible for the horse to take up to six months to show symptoms. This is not usually the case, however, as most show symptoms within 2-6 weeks. Once clinical symptoms are present, however, the horse will typically die within three to five days. While vaccinations do not entirely prevent the disease, rabies is uniformly fatal in unvaccinated horses. Unvaccinated horses that have been exposed to the virus must be euthanized or be quarantined for six months. Vaccinated horses that have been bitten or exposed should immediately be given a rabies booster, followed by 45 days of observation. Now is the perfect time to check in with your veterinarian on your horses’ vaccination status. Take caution and protect against risks by DR. KATIE HENNESSY when you can. This column is sponsored by Polk Equine, and the opinions expressed herein may not reflect those of CFAN or of its advertisers. BIO: Dr. Katie Hennessy graduated from the University of Illinois College of Veterinary Medicine in 2008 with a degree in large animal health and equine medicine. She completed an advanced internship at The Equine Medical Center of Ocala and is currently the owner and practicing veterinarian at Polk Equine. Her expertise ranges from small and exotic creatures to large animals, specializing in equine medicine.
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