Crop Knowledge Master Fungi

Fusarium Primer

General Information Summary
Pathogens & Hosts Taxonomy Characteristics Disease Types Management Graphics References

Authors

Andrew K. Gonsalves, Educational Specialist

Stephen A. Ferreira, Extension Plant Pathologist

Department of Plant Pathology, College of Tropical and Agriculture and Human Resources

University of Hawaii at Manoa

PATHOGENS & HOSTS

Over twenty-four Fusarium species have been reported to occur in Hawaii (Raabe, et al., 1981). The following is a list of the reported pathogens from this genus (Fusarium) and the hosts they infect. The list is organized by the scientific name of the pathogen species (CAPITAL LETTERS), followed by the various susceptible plant hosts. Words in blue indicate what symptom or disease a given pathogen causes on the listed hosts.

FUSARIUM AFFINE

Root Rot:

pineapple (Ananas comosus)

FUSARIUM CULMORUM

Dry Rot:

potato (Solanum tuberosum)

FUSARIUM DIMERUM

klu, kolu, etc (Acacia farnesiana)

FUSARIUM GRAMINEARUM

Head Blight:

cultivated oats (Avena sativa)

FUSARIUM MONILIFORME

Blight:

sorghum (Sorghum bicolor)

Leafspot:

Dracaena marginata

Root Rot:

sugarcane (Saccharum officinarum)

Seed Rot:

corn, maize (Zea mays)

Other:

Syagrus fulvitarsis

FUSARIUM MONILIFORME var. SUBGLUTINANS

Fruitlet Core Rot:

pineapple (Ananas comosus)

Heart Rot:

banana (Musa acuminata, AAA)

FUSARIUM OXYSPORUM

Root Rot:

prickly pear (Opuntia megacantha)

Stem Decay:

baby's breath (Gypsophila paniculata)

Wilt:

Assam rattlebox (Crotalaria assamica)

garden bean (Phaseolus vulgaris)

potato (Solanum tuberosum)

cowpea (Vigna sinensis)

pansy (Viola tricolor)

cultivated zinnia (Zinnia elegans)

Other:

Musa sp.

sugarcane (Saccharum officinarum)

FUSARIUM OXYSPORUM f.sp. ASPARAGI

Yellows:

cultivated asparagus (Asparagus officinalis var. altilis)

FUSARIUM OXYSPORUM f.sp. CALLISTEPHI

Wilt:

China aster (Callistephus chinensis)

FUSARIUM OXYSPORUM f.sp. CUBENSE

Panama Disease (wilt):

banana (Musa acuminata, AAA)

FUSARIUM OXYSPORUM f.sp. DIANTHI

Wilt:

carnation (Dianthus caryophyllus)

FUSARIUM OXYSPORUM f.sp. KOAE

koa (Acacia koa var. koa)

FUSARIUM OXYSPORUM f.sp. LYCOPERSICI

Wilt:

tomato (Lycopersicon esculentum)

FUSARIUM OXYSPORUM f.sp. MELONIS

Wilt:

muskmelon (Cucumis melo var. melo)

FUSARIUM OXYSPORUM f.sp. NIVEUM

Wilt:

watermelon (Citrullus vulgaris)

FUSARIUM OXYSPORUM f.sp. PISI

edible-podded pea (Pisum sativum var. macrocarpon)

FUSARIUM OXYSPORUM f.sp. TRACHEIPHILUM

Wilt:

soybean (Glycine max)

FUSARIUM OXYSPORUM f.sp. ZINGIBERI

Fusarium Yellows:

ginger (Zingiber officinale)

FUSARIUM RADICICOLA

Root Rot:

Persea sp.

Other:

Hibiscus sp.

potato (Solanum tuberosum)

FUSARIUM ROSEUM

Corm Rot:

taro (Colocasia esculenta)

Root Rot:

carnation (Dianthus caryophyllus)

FUSARIUM SOLANI

Corm Rot:

taro (Colocasia esculenta)

Dry Rot:

potato (Solanum tuberosum)

Root Rot:

papaya (Carica papaya)

sweet potato (Ipomoea batatas)

Persea sp.

Other:

ginger (Zingiber officinale)

FUSARIUM SOLANI f.sp. RADICICOLA

roselle (Hibiscus sabdariffa)

potato (Solanum tuberosum)

FUSARIUM SP.

Fruit Dry Rot:

papaya (Carica papaya)

Rhizomes Rot:

ginger (Zingiber officinale)

Root Rot:

Oncidium sp.

Stem and Root Rot:

sweet pea (Lathyrus odoratus)

Wilt:

China aster (Callistephus chinensis)

Other:

pineapple (Ananas comosus)

cultivated asparagus (Asparagus officinalis)

jack bean (Canavalia ensiformis)

sweet pepper (Capsicum frutescens = C. annum)

Cattleya sp.

dasheen (Colocasia esculenta var. globulifera)

nut grass (Cyperus rotundus)

Dendrobium sp.

carnation (Dianthus caryophyllus)

star jasmine (Jasminum multiflorum, syn. = J. pubescens)

blue lupine (Lupinus hirsutus)

Lupinus sp.

tomato (Lycopersicon esculentum)

alfalfa (Medicago sativa)

Phalaenopsis sp.

pea (Pisum sativum)

sugarcane (Saccharum officinarum)

eggplant (Solanum melongena)

bird-of-paradise (Strelitzia reginae)

Vanda sp.

FUSARIUM VASINFECTUM

Crotalaria spectabilis

TAXONOMY

KINGDOM: Mycetae (fungi)

DIVISION: Eumycota

SUBDIVISION: Deuteromycotina (The imperfect fungi)

CLASS: Hyphomycetes

ORDER: Hyphales (Moniliales)

GENERAL CHARACTERISTICS

Fusarium spp. are higher fungi whose sexual stage is unknown (Agrios, 1988). Due to the great variabilty within this genus, it is one of the most difficult of all fungal groups to distinguish taxonomically (Alexopoulus and Mims, 1979). Conida are hyaline and can be divided into three groups: macroconidia, microconida, and chlamydospores. Macroconidia are several-celled, crescent or canoe-shaped spores. Their ends vary in that some species produce sharply pointed macroconidia, while others produce spores with rounder ends. The shape of these spores are used to differentiate between the different species (Toussoun and Nelson, 1968). The majority of Fusarium species isolated produce their macroconidia on sporodochia. However, macroconidia can also be found throughout the aerial mycelium. Microconidia are one or two-celled, ovoid or oblong, and borne singly or in chains. These spores are found scattered throughout the aerial mycelium. Since the microconidia are either one- or two-celled, they are usually smaller than the macroconidia. Both macroconida and microconidia are produced from phialides. Chlamydospores are round, one- or two-celled, thick-walled spores produced terminally or intercalary on older mycelium (Agrios, 1988). Most species of Fusarium produce sporodochia from which the conidia are formed. Because of the great amount of variability within this genus, refer to the more specific Fusarium summaries (i.e., Fusarium oxysporum) for more detailed information.

Colony morphology and pigmentation are variable in culture and are, thus, not useful in differentiating between species.

Fusarium is also one of the fungal genera that produce mycotoxins. As of 1984, at least 20 toxins had been described from about 30 species of Fusarium (Moss and Smith, 1984). Fusarium produces its toxins primarily on corn and other grains infected in the field or after corn is in storage (Agrios, 1988). Some toxins produced by Fusarium sp. on corn induce vomiting in swine.

TYPES OF DISEASES

Fusarium or vascular wilt is the major disease caused by this pathogen on several different hosts. Fusarium spp. also cause root, stem, and corm rots under field or greenhouse conditions; and pink or yellow molds of fruits during postharvest storage. The postharvest diseases occur on vegetables and ornamentals, and especially on root crops, tubers, and bulbs.

DISEASE CYCLE

The Fusarium spp. that cause vascular wilts can be spread in soil, dust, and irrigation water (Smith et al., 1988). Wind, rain, farm equipment, and decaying plant tissue can also help to spread the fungus.

Fusarium is a soil inhabitant which overwinters between crops in infected plant debris as mycelium and in its three spore forms. It can remain in the soil for long periods of time, including fallow periods. Healthy plants can become infected through their root tips; either directly, through wounds, or at the point of formation of lateral roots (Agrios, 1988). The fungus grows as mycelium through the root cortex intercellularly, ultimately advancing to the vascular tissue. As the mycelium continues to grow - usually upward toward the stem and crown - it branches and produces microconida. The proliferation of fungal growth in the plant's vascular tissue eventually causes the plant to wilt and die. The fungus can continue to grow on the decaying tissue where it can sporulate profusely. At this point, the spores can be spread to other plants or areas by wind, water, or through the movement of soil (Agrios, 1988). On occasion, the fungus can reach the fruit and contaminate the seed. This occurs when the soil moisture is high and the temperature is relatively low (Agrios, 1988).

In addition the vascular wilting, the fungus can infect other parts of the plant close to the soil to induce root, stem, and corm rots. When seedlings are infected with Fusarium, damping-off may occur. If harvested fruits are contaminated with the fungus, postharvest diseases such as "pink or yellow molds" on vegetables and ornamentals can develop. This is especailly important on root crops (tubers and bulbs), as well as on low-lying crops like cucurbits and tomatoes (Agrios, 1988).

MANAGEMENT

Since it is difficult to get rid of Fusarium once it contaminates the soil, proper sanitation measures should be followed to prevent the spread of this pathogen to Fusarium-free soil.

For specific information concerning management of Fusarium diseases, the individual summaries for the Fusarium sp. should be consulted. However, the following is a summary of control measures for Fusarium Wilt of Tomato that may be useful to get an overview of the measures involved with managing Fusarium diseases (Nelson et al., 1981).

1. Use resistant cultivars where available.

2. Use soil fumigants if available and if economically feasible.

3. Manipulate soil fertility in such a way to decrease the growth, sporulation, and virulence of the pathogen.

A. Add lime amendments to obtain soil pH of at least 7.0.

B. Avoid excessive use of phosphorus and magnesium soil amendments.

C. Avoid excessive use of phosphorus and magnesium soil amendments.

D. Use nitrate rather than ammonium-nitrogen.

E. Apply fertilizers as bands close to tomato roots, do not broadcast apply.

F. Permit soil to be fallow prior to planting.

4. Avoid the use of diseased transplants or infested seed.

5. Prevent dissemination of the pathogen by eliminating movement of infested soil into disease-free areas (Nelson et al., 1981).

GRAPHICS

Below is a list of graphics that are available for this Genus:

Fusarium rot of corn

Wilt (stem damage) of watermelon

This may be caused by Fusarium oxysporum f.sp. niveum.

REFERENCES

Agrios, G.N. 1988. Plant Pathology, 3rd edition. Academic Press, Inc: San Diego. 803 pp.

Farr, , D.F., G.F. Bills, G.P. Chamuris, and A.Y. Rossman. 1989. Fungi on Plants and Plant Products in the United States. APS PRESS: St. Paul, Minnesota. 1252 pp.

Moss, M.O. and J.E. Smith. 1984. The Applied Mycology of Fusarium: Symposium of the British Mycological Society held at Queen Mary College, London, September 1982. Cambridge University Press: Cambridge. 264 pp.

Nelson, P.E., T.A. Toussoun, and R.J. Cook, eds. 1981. Fusarium: Diseases, Biology, and Taxonomy. The Pennsylvania State University Press: University Park, Pennsylvania. 457 pp.

Raabe, Robert D., Ibra L. Conners, and Albert P. Martinez. 1981. Checklist of Plant Diseases in Hawaii. Hawaii Institute of Agriculture and Human Resources, College of Tropical Agriculture and Human Resources, University of Hawaii (Information Text Series 022).

Streets, R.B. 1982. The Diagnosis of Plant Diseases: a field and laboratory manual emphasizing the most practical methods for rapid identification. The University of Arizona Press: Tucson, Arizona.

Toussoun, T.A. and P.E. Nelson. 1968. A Pictorial Guide to the Identification of Fusarium species according to the taxonomic system of Snyder and Hansen. The Pennsylvania State Universtiy Press: University Park, Pennsylvania. 51 pp.

 

 

JUNE 1994

 

1-FUSARI

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