Palm Diseases

Select one of the diseases below to learn more and see how they effect palms.

I#We are fortunate indeed that, relative to most landscape plants, a well-grown palm remains fairly free of damaging pests. Nevertheless, certain insects and diseases will occasionally attack landscape palms in sufficient force to warrant control measures. MORE...

 

 

Recommended Reading

 

 

Ganoderma Butt Rot (1.58M PDF)
Three phases of basidiocarp (conk) development of Ganoderma zonatum. The white "button" near the top of the picture is the beginning stage of the conk. The lower-right structure is a mature conk. The lower-left structure is also a mature conk, but it is an old one; the underside of this conk is no longer white. Select to view larger image. Cross-sections of lower trunk of Syagrus romanzoffiana infested with Ganoderma zonatum. Top-left section is bottom section (section 1) and remaining sections progress up the trunk. Note darkening of wood due to fungal degradation (rot). Select to view larger image. Comparison of pygmy date palm sections that are either healthy (right) or diseased (left) with Ganoderma zonatum. Select to view larger image. Basidiocarp (conk) of Ganoderma zonatum. Note glazed reddish-brown top surface and white undersurface. The "straight" side of the conk is directly attached to the trunk. There is no "stem" or "stalk" that attaches the conk to the trunk. Select to view larger image.
Photo Credits: M. L. Elliott, University of Florida

Fusarium Wilt (292K PDF)
One-sided death of leaflets is typical of Fusarium wilt. Select to view larger image.
 Reddish-brown stripe on leaf petiole is on same side that exhibited one-sided death of leaflets due to Fusarium wilt. Select to view larger image.
Progressive death of leaves up through the canopy due to Fusarium wilt. Note that the right side of the upright leaf at top of canopy is exhibiting the one-sided death of leaflets typical of Fusarium wilt. Select to view larger image.
Photo Credits: T.K. Broschat, N.A. Harrison, University of Florida

False Smut (Graphiola Leaf Spot) (626K PDF)
Close-up of sori of Graphiola phoenicis with filaments protruding. Select to view larger image. The small black bodies are sori (fruiting bodies) of Graphiola phoenicis that have erupted through the leaflet epidermis. Select to view larger image.
Heavy infestation of Graphiola leaf spot. Select to view larger image.
Potassium deficiency symptoms and Graphiola phoenicis sori on the same leaf. Select to view larger image.
Photo Credits: M.L. Elliott, G.W. Simone, D.L. Caldwell, T.K. Broschat, University of Florida

Pestalotiopsis Diseases (116K PDF)
Expanding spots on both leaflets and rachis of Pseudophoenix sargentii caused by Pestalotiopsis. Select to view larger image. Petiole lesion on Phoenix roebelenii due to Pestalotiopsis. Select to view larger image. Note dark lesions caused by Pestalotiopsis on petioles of this Phoenix roebelenii, especially at base of young leaves emerging from bud. Select to view larger image.
Photo Credits: T.K. Broschat, University of Florida

Leaf Spots & Leaf Blights (464K PDF)
Leaf spots on palm leaflets. These are brown with a chlorotic (yellow) halo. Note that as spots increase in number and size that there is a merging of dead tissue (blight). Select to view larger image. Leaf spots often change in color and size as the disease progresses. Select to view larger image. Leaf spots often change in color and size as the disease progresses. Select to view larger image. These leaf spots on Wodyetia bifurcata are necrotic tissue surrounded by a brown halo. They are often observed when iron deficiency is also a problem, as shown in this photo. Select to view larger image
Photo Credits: M.L. Elliott, T.K. Broschat, University of Florida

Thielaviopsis Trunk Rot (1.28M PDF)
Cocos nucifera trunk collapsed upon itself due to Thielaviopsis trunk rot. Select to view larger image.
 The canopy of this Phoenix canariensis fell off of the trunk due to Thielaviopsis trunk rot. Select to view larger image. Cross-section of Cocos nucifera trunk illustrating that the rot caused by Thielaviopsis paradoxa occurs on only one side of the trunk and moves from the outside to the inside of the trunk. Select to view larger image.
Stem bleeding on a Cocos nucifera due to infection from Thielaviopsis paradoxa. Select to view larger image.
Photo Credits: M.L. Elliott, H. Donselman, University of Florida

Bud Rots (772K PDF)
Spear leaf and next youngest leaf exhibiting typical symptoms of Phytopthora bud rot. Select to view larger image. Bud rot of Cocos nucifera: no new leaves are emerging and crown is open-topped, while older leaves in canopy look healthy at this time. Select to view larger image. This is the same palm as shown in Figure 2, but six months later. Still no new leaves being produced and older leaves are now declining. Select to view larger image. Multiple Washingonia robusta in this field nursery are being affected by Phytophthora bud rot. Those most affected were juvenile palms in a low-lying area. Select to view larger image.
Photo Credits: M.L. Elliott, T.K. Broschat, University of Florida

Petiole (Rachis) Blights (851K PDF)
Reddish-brown streak along petiole of Washingtonia robusta due to Petiole Blight. Select to view larger image.
 Close-up of discolored petiole streak. Select to view larger image. Reddish-brown lesion on petiole disrupts vascular tissue which kills leaflets within the leaf blade. Select to view larger image. Sporulating structures of Cocoicola on a Washingtonia robusta petiole. Select to view larger image.
Photo Credits: M.L. Elliott, A. Wilson, University of Florida

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Lethal Yellowing (2.84M PDF)
A colony of Aceria guerreronis Keifer, a cFoliar yellowing symptoms of Cocos nucifera due to Lethal Yellowing. Select to view larger image.
Foliar yellowing symptoms of Lethal Yellowing on Caryota mitis. Select to view larger image.
Foliar browning symptoms of Lethal Yellowing on Phoenix sylvestris. Select to view larger image.
Leaf kink along petiole due to Lethal Yellowing on Adonidia merrillii. Select to view larger image.
Photo Credits: T.K. Broschat, N.A. Harrison, University of Florida