A disease called Texas Phoenix palm decline continues to move north and is now in Hillsborough County.
The University of Florida Hillsborough County Extension recently presented a seminar on this disease, well attended by professional tree service personnel, forestry employees and nursery owners. If these busy professionals are attending a seminar, you know it is important to their industry.
Most of the information in this article came from information provided by University of Florida researchers or the experts who attended the seminar.
It's important to homeowners because landscape palms will die if not treated for this phytoplasma disease.
Phytoplasma is any of a group of extremely small bacteria that have a cell membrane instead of cell walls and can assume a variety of shapes, but are parasitic solely in plants. They invade cells of the food-carrying tissue known as phloem and are usually spread by plant-sucking insects, such as the leafhopper, which draws its food from phloem.
This invasion of the phloem eventually leads to the death of the plant, in this case the palm.
The four main symptoms appear exactly the same as those associated with lethal yellowing disease of Phoenix species. The first and most obvious for a mature palm is the sudden drop of most of the fruit. Second, there's browning and death of newly opening flower spikes.
Third you will notice a discoloration of the foliage, beginning with the oldest fronds. The fronds normally do not turn yellow, and if so it is only briefly. The discoloration begins at leaf tips. You'll notice a higher than usual number of lower fronds dying. At times it may be difficult to recognize this symptom if the dead and dying fronds are removed often.
Once about one-third of the fronds have died, the spear leaf dies. This indicates that the bud, or "heart," of the palm has died. Once this happens, there will be no new leaves, and the existing leaves will continue to die.
Mature roots at or near the surface become soft and are easily broken. The palm may actually rock back and forth in the soil if you give it a shove.
The University of Florida researchers recommend that palms be treated as soon as possible after infection. The treatment, which can also be used as a preventive one, consists of inoculating palms with oxytetracycline hydrochloride. Tree Saver is the exclusive provider of OTC in Florida.
Rob Northrop, extension forester with the University of Florida's Institute of Food and Agricultural Sciences, recommended that aside from beginning an inoculation program, tree owners should replant less susceptible palms and diversify their landscape with a mixture of hardwoods and palms. The use of insecticides is not recommended and has not shown to be of any help.
A local company, Save Our Palms, has begun inoculating palms through trunk injections, said owner Gene Layton. Palms most commonly treated in this area are the cabbage palm, Canary Island date palm, Medjool date palm and Washingtonia.
Costs can run from $7 to $10 per tree per quarter for trees that can cost thousands to replace.