Texas root rot
Encyclopedia
Texas root rot is a
pathogen
fairly common in Mexico
and the southwestern
United States
that causes sudden wilt
and death
of
affected plant
s, usually during the warmer months. It is a
soil-borne fungus
of the species
Phymatotrichopsis omnivora that attacks the root
s of
susceptible plants. Because the damaged roots are unable to
take up enough water
to maintain the plant in warm weather,
the leaves wilt and the plant dies. The
dead leaves usually remain attached to the plant.
A multitude of dicotyledon
ous tree, shrub and herbaceous plants are susceptible to
Texas root rot, including fig
s, pomegranate
s, elm
s, grape
s,
cotton
, alfalfa
, oleander
, and rose
s. The largest compilation of hosts, more than 1,700, was made by J. Taubenhaus
and W. Ezekiel. It is
one of the most destructive fungal plant diseases. Some
monocot plants are tolerant and others are immune.
Eradication or control of Texas root rot is difficult, at best.
The fungus is known to thrive in moist and alkaline
soil
s. It can survive for long periods in the soil,
sometimes lying dormant for decades, and can penetrate to
depths of up to twelve feet. Increasing the organic
content of the soil with compost
and green manure
may
help to reduce growth of the fungus.
A monograph of this disease, which includes a historical review, was written by Streets and Bloss in 1973.
pathogen
Pathogen
A pathogen gignomai "I give birth to") or infectious agent — colloquially, a germ — is a microbe or microorganism such as a virus, bacterium, prion, or fungus that causes disease in its animal or plant host...
fairly common in Mexico
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
and the southwestern
United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
that causes sudden wilt
Wilting
Wilting refers to the loss of rigidity of non-woody parts of plants. This occurs when the turgor pressure in non-lignified plant cells falls towards zero, as a result of diminished water in the cells...
and death
Death
Death is the permanent termination of the biological functions that sustain a living organism. Phenomena which commonly bring about death include old age, predation, malnutrition, disease, and accidents or trauma resulting in terminal injury....
of
affected plant
Plant
Plants are living organisms belonging to the kingdom Plantae. Precise definitions of the kingdom vary, but as the term is used here, plants include familiar organisms such as trees, flowers, herbs, bushes, grasses, vines, ferns, mosses, and green algae. The group is also called green plants or...
s, usually during the warmer months. It is a
soil-borne fungus
Fungus
A fungus is a member of a large group of eukaryotic organisms that includes microorganisms such as yeasts and molds , as well as the more familiar mushrooms. These organisms are classified as a kingdom, Fungi, which is separate from plants, animals, and bacteria...
of the species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
Phymatotrichopsis omnivora that attacks the root
Root
In vascular plants, the root is the organ of a plant that typically lies below the surface of the soil. This is not always the case, however, since a root can also be aerial or aerating . Furthermore, a stem normally occurring below ground is not exceptional either...
s of
susceptible plants. Because the damaged roots are unable to
take up enough water
Water
Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...
to maintain the plant in warm weather,
the leaves wilt and the plant dies. The
dead leaves usually remain attached to the plant.
A multitude of dicotyledon
Dicotyledon
The dicotyledons, also known as dicots, are a group of flowering plants whose seed typically has two embryonic leaves or cotyledons. There are around 199,350 species within this group...
ous tree, shrub and herbaceous plants are susceptible to
Texas root rot, including fig
Ficus
Ficus is a genus of about 850 species of woody trees, shrubs, vines, epiphytes, and hemiepiphyte in the family Moraceae. Collectively known as fig trees or figs, they are native throughout the tropics with a few species extending into the semi-warm temperate zone. The Common Fig Ficus is a genus of...
s, pomegranate
Pomegranate
The pomegranate , Punica granatum, is a fruit-bearing deciduous shrub or small tree growing between five and eight meters tall.Native to the area of modern day Iran, the pomegranate has been cultivated in the Caucasus since ancient times. From there it spread to Asian areas such as the Caucasus as...
s, elm
Elm
Elms are deciduous and semi-deciduous trees comprising the genus Ulmus in the plant family Ulmaceae. The dozens of species are found in temperate and tropical-montane regions of North America and Eurasia, ranging southward into Indonesia. Elms are components of many kinds of natural forests...
s, grape
Grape
A grape is a non-climacteric fruit, specifically a berry, that grows on the perennial and deciduous woody vines of the genus Vitis. Grapes can be eaten raw or they can be used for making jam, juice, jelly, vinegar, wine, grape seed extracts, raisins, molasses and grape seed oil. Grapes are also...
s,
cotton
Cotton
Cotton is a soft, fluffy staple fiber that grows in a boll, or protective capsule, around the seeds of cotton plants of the genus Gossypium. The fiber is almost pure cellulose. The botanical purpose of cotton fiber is to aid in seed dispersal....
, alfalfa
Alfalfa
Alfalfa is a flowering plant in the pea family Fabaceae cultivated as an important forage crop in the US, Canada, Argentina, France, Australia, the Middle East, South Africa, and many other countries. It is known as lucerne in the UK, France, Australia, South Africa and New Zealand, and known as...
, oleander
Oleander
Nerium oleander is an evergreen shrub or small tree in the dogbane family Apocynaceae, toxic in all its parts. It is the only species currently classified in the genus Nerium. It is most commonly known as oleander, from its superficial resemblance to the unrelated olive Olea, but has many other...
, and rose
Rose
A rose is a woody perennial of the genus Rosa, within the family Rosaceae. There are over 100 species. They form a group of erect shrubs, and climbing or trailing plants, with stems that are often armed with sharp prickles. Flowers are large and showy, in colours ranging from white through yellows...
s. The largest compilation of hosts, more than 1,700, was made by J. Taubenhaus
Jacob Joseph Taubenhaus
Dr. Jacob Joseph Taubenhaus, born in Safed, Palestine on October 20, 1884, was Chief of the Division of Plant Pathology and Physiology of the Texas Agricultural Experiment Station at the Agricultural and Mechanical College of Texas from 1916 until his death on December 13, 1937...
and W. Ezekiel. It is
one of the most destructive fungal plant diseases. Some
monocot plants are tolerant and others are immune.
Eradication or control of Texas root rot is difficult, at best.
The fungus is known to thrive in moist and alkaline
soil
Soil
Soil is a natural body consisting of layers of mineral constituents of variable thicknesses, which differ from the parent materials in their morphological, physical, chemical, and mineralogical characteristics...
s. It can survive for long periods in the soil,
sometimes lying dormant for decades, and can penetrate to
depths of up to twelve feet. Increasing the organic
Organic compound
An organic compound is any member of a large class of gaseous, liquid, or solid chemical compounds whose molecules contain carbon. For historical reasons discussed below, a few types of carbon-containing compounds such as carbides, carbonates, simple oxides of carbon, and cyanides, as well as the...
content of the soil with compost
Compost
Compost is organic matter that has been decomposed and recycled as a fertilizer and soil amendment. Compost is a key ingredient in organic farming. At its most essential, the process of composting requires simply piling up waste outdoors and waiting for the materials to break down from anywhere...
and green manure
Green manure
In agriculture, a green manure is a type of cover crop grown primarily to add nutrients and organic matter to the soil. Typically, a green manure crop is grown for a specific period of time , and then plowed under and incorporated into the soil while green or shortly after flowering...
may
help to reduce growth of the fungus.
A monograph of this disease, which includes a historical review, was written by Streets and Bloss in 1973.