A new disease (Fusarium decline) has recently been spotted in Broward County, which is killing the ubiquitous Queen palms (Syagrus romanzoffiana) as well as Mexican fan palms (Washingtonia robusta). I have gotten unconfirmed, but reliable, reports of this disease from both Cooper City and Davie. 

 A description of the disease symptoms may be found in the excerpt below:

Queen palm

Symptoms on queen palms (a featherleaf palm) are as follows. The lowest (oldest) 2-3 leaves turn brown (leaflets and petiole) but do not break or hang down (Figure 1). The next 2-3 youngest leaves in the canopy will turn varying shades of yellow. This pattern continues up through the canopy (Figure 2) until the entire canopy is brown. It looks as if the canopy has been freeze-dried in place (Figures 3 and 4). The time between initial symptoms and palm death is only a few months. The symptoms are different from early senescence of leaves with potassium deficiency, a common nutrient deficiency of queen palms. With severe potassium deficiency, the leaflets will be brown but the petiole will be green. With the new disease, both the leaflets and the petiole are brown.

Mexican fan palm

Symptoms on Mexican fan palms will also have more brown (necrotic) lower leaves than normal and subsequently younger leaves with leaf blades that are partly green and partly yellow or brown (Figure 8). The petioles of these leaves will have a brown to reddish-brown stripe running from the blade back to the trunk (Figure 9). Again, it appears to be a relatively short time (a few months) between initial symptom development and palm death. Cross-sections through the striped petiole reveals an associated internal discoloration. The individual leaf symptoms (brown stripe with uneven leaf blade coloration) will look the same as another disease that can be observed on Mexican fan palms, petiole blight. Petiole blight is not normally a fatal disease, whereas Fusarium decline is fatal.

More Information on this disease can be found in the full IFAS article here:  Fusarium decline. PDF.