Isles of Capri and Marco Island also continue to be active areas for this disease. Previous areas of activity in the county include:
Naples Park (102nd and 94th avenues)
Henderson Creek and County Road 951
Isles of Capri and Marco Island
Please report suspect lethal yellowing disease palms on Marco Island to the environmental specialist, Nancy Richie (389-5003). The county is currently inoculating 525 palms three times a year. Coconut, Christmas and Canary Island date palms are all susceptible to the disease.
This service is free to residents. Please report suspicious palms located outside the city limits palms that are among the susceptible species listed above to me. If palms are inside the city limits, call Joe Boscaglia, 213-7123.
Please don't call if it is a queen, royal or cabbage palm, as this is one disease these species and other native palms do not get. Washingtonia, areca, Alexandra, Carpentaria, Ptychosperma, foxtail and pygmy date palms have not been reported to succumb from this disease. However, the disease has been found on 38 other species of palms and screwpine. If the coconut palm still has fruit, I don't usually consider it a high probability of being infected.
As part of the suppression program, the county will remove a palm, at no expense, if it is caught early and still has some green fronds. If there is no green left in the fronds, the little planthopper won't feed on the palm nor be able to spread the disease.
The planthopper vectors this bacterial plant disease, much as mosquitoes vector human diseases. The palm bacteria plug up the plant's vascular system and it dies rapidly, within five to seven months. Symptoms vary with the coconut cultivar and palm species.
Usually two of these symptoms are a strong indication of this disease:
Coconut: Fruits drop and the stem-end is water-soaked or flower tips emerge chocolate brown, drooping instead of upright. Leaf symptoms vary with palm species, and coconut varieties.
Jamaican Tall: third or fourth new leaf turns yellow; oldest fronds drop parallel to trunk; no leaf wilt symptoms
Malayan: Wilt symptoms only, with individual leaflets wilted and folded up; no yellowing
Christmas: similar to Jamaican Tall but without yellowing; oldest leaves may bronze
Pritchardia: Spear leaf death is first symptom.
For pictures of lethal yellowing symptoms and inoculators that are using currently approved methods, see: collier.ifas.ufl.edu/Horticulture/palmyellowing.htm
Malayan Dwarf and Maypan varieties were previously thought to be resistant to this disease, but the University of Florida has reported losses of 70 percent and 83 percent respectively in their research plots. It is highly risky to purchase palms from central Florida and east coast nurseries.
There is less likelihood of palms being infected if they are west coast grown. Other areas have severe problems with this disease and importing palms from infected areas has caused large losses of palms in Collier County.
Doug Caldwell is the commercial landscape horticulture extension agent and landscape entomologist with the University of Florida Collier County Extension Service. E-mail: firstname.lastname@example.org. Call 353-4244, ext. 203. For updates on Southwest Florida Horticulture visit: collier.ifas.ufl.edu.