Pestalotiopsis (Pestalotia) Diseases of Palm - Hillsborough County

PP-217 

Pestalotiopsis (Pestalotia) Diseases of Palm 1 

Monica L. Elliott 2 

Summary 

• Pestalotiopsis is a fungus that causes diseases 

of both the palm leaf petiole and leaf blade, often 

at the same time. Palm leaf diseases caused by 

Pestalotia are the same as those caused by 

Pestalotiopsis. 

• Many palms are hosts to these fungi. However, 

the disease is often observed in Florida on 

Phoenix roebelenii (pygmy date palm), where it 

can cause a fatal bud rot. 

• Leaf spots will begin as very small, yellow, 

brown or black spots that enlarge in size. The 

spot usually turns gray with a black outline. 

Lesions on the petiole and rachis are similar. 

• Symptoms may occur on multiple leaves at 

once, especially on juvenile palms. 

• Sanitation and water management are critical 

for disease management, especially in a nursery 

(both container and field). Injury prevention and 

good palm nutrition are part of the overall 

management strategy. 

• Fungicides may be useful as part of an 

integrated management program, but they should 

never be the sole component of a program. 

Introduction 

The fungus Pestalotiopsis causes leaf spots, 

petiole/rachis blights and sometimes a bud rot of 

palms. In other words, unlike the other leaf spot and 

petiole blight pathogens, which attack either the leaf 

blade or the leaf petiole, Pestalotiopsis attacks all 

parts of the leaf from base to tip. It is also one of the 

more ubiquitous fungi in the palm canopy, and is 

easily isolated from healthy palm tissue. 

For information on other leaf spots and 

petiole/rachis blights, refer to the following 

documents: Leaf Spots and Leaf Blights of Palm at 

htttp://edis.ifas.ufl.edu/pp142; and Petiole/Rachis 

Blight of Palm at http://edis.ifas.ufl.edu/pp145. 

Pathogen and Hosts 

Pestalotiopsis palmara is the primary, but not the 

only, Pestalotiopsis species associated with palms. 

References in the literature to Pestalotia are probably 

the same disease, as it is difficult to distinguish 

between these two genera of fungi. 

As indicated previously, Pestalotiopsis can be 

readily isolated from healthy palm tissue. The fungus 

is not host specific, and has been isolated from a wide 

variety of palms. 

1. This document is Fact Sheet PP-217, one of a series of the Plant Pathology Department, Florida Cooperative Extension Service, Institute of Food and 

Agricultural Sciences, University of Florida. Original publication date January 2006. Visit the EDIS Web Site at http://edis.ifas.ufl.edu. 

2. M. L. Elliott, professor, Plant Pathology Department, Fort Lauderdale Research and Education Center--Ft. Lauderdale, FL; Florida Cooperative Extension 

Service, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL. 

The Institute of Food and Agricultural Sciences (IFAS) is an Equal Opportunity Institution authorized to provide research, educational information and 

other services only to individuals and institutions that function with non-discrimination with respect to race, creed, color, religion, age, disability, sex, 

sexual orientation, marital status, national origin, political opinions or affiliations. U.S. Department of Agriculture, Cooperative Extension Service, 

University of Florida, IFAS, Florida A. & M. University Cooperative Extension Program, and Boards of County Commissioners Cooperating. Larry 

Arrington, Dean


It has been demonstrated that the fungus usually 

requires wounds for the plant penetration (infection) 

necessary for disease development. It is not 

uncommon to isolate Pestalotiopsis and another 

pathogen from the same diseased tissue. In most 

cases, it is likely the other pathogen was the primary 

pathogen (the fungus that invaded the healthy plant 

tissue first), and Pestalotiopsis invaded via the wound 

created by the primary pathogen. In Elaeis guineensis 

(African oil palm), it is well-documented that insect 

damage is necessary for disease development. 

Symptoms 

Disease development by Pestalotiopsis can be 

restricted to only the leaf blade (leaflets or leaf 

segments) or only the petiole and rachis; or, it can 

develop on both tissues at the same time (Figure 1). 

Spots will begin as very small yellow, brown or black 

spots. If the disease is restricted, the spots may never 

be more than 1/4 inch in size. Under optimum 

environmental conditions, the spots may expand and 

increase in number until they merge (coalesce) to 

form a leaf blight or rachis blight (larger area of 

affected tissue) (Figure 2). Often, the spots turn a 

grayish color that are outlined in black. The same 

type of lesions occurs on the petiole or rachis of the 

palm. One may even see lesions occur on leaf spines. 

Figure 2. Petiole lesion on Phoenix roebelenii due to 

Pestalotiopsis. Credits: T.K. Broschat 

If the pathogen is causing a rachis or petiole 

blight, the disease is a more serious problem for two 

reasons. First, as the pathogen destroys tissue in the 

rachis or petiole, it will affect the vascular tissue 

which in turn affects tissue in the leaflets or leaf 

segments. Second, the pathogen may spread down 

the rachis or petiole to the apical meristem (bud) 

region and affect the growing point of the palm. 

While all palms are probably susceptible to 

diseases caused by this fungus, pgymy date palm 

(Phoenix roebelenii) appears to be affected quite 

often in Florida, especially during the winter months. 

With these palms, a bud rot has been observed that 

can kill the palm (Figure 3). This has been observed 

on juvenile and mature palms. 

Figure 1. Expanding spots on both leaflets and rachis of 

Pseudophoenix sargentii caused by Pestalotiopsis. 

Credits: T.K. Broschat 

If the pathogen is restricted to only causing leaf 

spots, the disease may not be very damaging to the 

palm, especially a mature palm in the landscape. 

However, with juvenile palms that have no trunk and 

only a few leaves, the palm could be severely affected 

by the leaf spots. 

Figure 3. Note dark lesions caused by Pestalotiopsis on 

petioles of this Phoenix roebelenii, especially at base of 

young leaves emerging from bud. Credits: T.K. Broschat


Diagnosis 

The exact diagnosis of Pestalotiopsis diseases is 

based on identification of the fungal pathogen. The 

pathogen is identified by examining the fungal spores. 

These may be examined directly on the plant tissue if 

spores are being produced, or by placing the diseased 

tissue in a moist chamber to induce sporulation. 

Isolation of the pathogen can be made on artificial 

media, and this growth then induced to sporulate. 

It is not uncommon to observe or isolate more 

than one potential pathogen from the same diseased 

tissue. In some cases, it is apparent which fungus was 

the first pathogen to invade the healthy tissue, while 

the second fungus moved into the resulting necrotic 

(dead) tissue as a saprobe. 

The Florida Extension Plant Disease Clinic 

(FEPDC) network is available for pathogen 

identification. Contact your local county Extension 

office or FEPDC for details on sample submission and 

cost of a laboratory diagnosis. 

Disease Management 

Pestalotiopsis produces abundant spores that can 

be easily dispersed by wind and water movement 

(splashing from rain or irrigation), so sanitation and 

water management are critical. Wounds or plant 

damage often seems to be a prerequisite for disease 

development, either naturally or from insects, other 

pathogens, nutrient deficiencies or human activity. 

Water management requires limiting the length 

of time when the leaves are wet or exposed to high 

humidity levels. This includes elimination of 

overhead irrigation or irrigating in the early morning 

hours when dew is already present. Leaf wetness can 

also be decreased by increasing air circulation and 

increasing plant spacing. 

In a nursery situation, severely diseased leaves 

should be pruned and destroyed to reduce spores 

available to infect healthy tissue. If the palm is small 

with only a few leaves, eliminate the palm completely. 

In the landscape or field nursery where nutrient 

deficiencies are often problematic, pruning diseased 

leaves may make the deficiency worse. Thus, one 

needs to decide which is or will debilitate the palm 

most – the disease or the nutrient deficiency. In 

many situations, the nutrient deficiency causes 

chlorosis (yellow) and necrosis (death) of the leaf 

tissue, creating the wound necessary for 

Pestalotiopsis infection. By eliminating the 

deficiency symptoms, one prevents disease 

development also. Thus, proper nutrient management 

is critical for disease prevention and management. 

While fungicides may be useful to prevent 

further spread of the disease, they are merely a 

supplement to water management, sanitation, injury 

prevention and good palm nutrition. Fungicides alone 

will not solve the problem. It is critical to understand 

that fungicides do not cure the leaf spot or petiole 

blight already present. Once a leaf spot or petiole 

lesion occurs, it will remain for the duration of the 

life of that leaf. Fungicides are used to prevent 

further spread of the disease by protecting leaf tissue 

that has not been infected by the fungal pathogen. 

In the nursery situation, prune severely diseased 

leaves prior to fungicide application. These leaves 

need to be removed anyway, and this will reduce the 

amount of fungicide used in the process. In the 

landscape situation, unless the leaf spot disease is 

severe, leaf pruning is not recommended unless the 

palm is free of nutrient deficiencies. In general, 

nutrient deficiencies are far more debilitating to the 

landscape palm than leaf spot diseases. 

Fungicide trials to examine efficacy of these 

products on palms have not been extensive. Foliar 

application of broad-spectrum fungicides would be 

suggested. Examples include, but are not limited to, 

products with the active ingredients mancozeb or 

chlorothalonil. 

Selected References 

Uchida, J. Y. 2004. Pestalotiopsis diseases. Pages 

27-28 in: Diseases and Disorders of Ornamental 

Palms. M. L. Elliott, T. K. Broschat, J. Y. Uchida, 

and G. W. Simone, eds. American Phytopathological 

Society, St. Paul, MN.

Pestalotiopsis (Pestalotia) Diseases of Palm - Hillsborough County

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