Fusarium patch is a disease in

turf grass A lawn is an area of soil-covered land planted with grasses and other durable plants such as clover which are maintained at a short height with a lawnmower (or sometimes grazing animals) and used for aesthetic and recreational purposes. L ...

settings also called pink snow mold or Microdochium patch. In many cool season grass species in North America, it is caused by the

fungus A fungus ( : fungi or funguses) is any member of the 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, separately fr ...

''Microdochium nivale'' . The white-pink

mycelium Mycelium (plural mycelia) is a root-like structure of a fungus consisting of a mass of branching, thread-like hyphae. Fungal colonies composed of mycelium are found in and on soil and many other substrates. A typical single spore germinates ...

on infected leaf blades is a distinguishing characteristic of the ''Microdochium nivale'' pathogen. Fusarium patch is considered economically important in the turf grass industry because of its tendency to cause significant injury to golf greens, thereby decreasing putting surface quality. Dissimilar from other snow molds, such as gray snow mold, ''Microdochium nivale'' does not need snow cover to cause widespread

infection An infection is the invasion of tissues by pathogens, their multiplication, and the reaction of host tissues to the infectious agent and the toxins they produce. An infectious disease, also known as a transmissible disease or communicable di ...

Hosts and symptoms

''M. nivale'' can infect all cool-season turf

grass Poaceae () or Gramineae () is a large and nearly ubiquitous family of monocotyledonous flowering plants commonly known as grasses. It includes the cereal grasses, bamboos and the grasses of natural grassland and species cultivated in lawns a ...

species. Annual bluegrass (''

Poa annua ''Poa annua'', or annual meadow grass (known in America more commonly as annual bluegrass or simply poa), is a widespread low-growing turfgrass in temperate climates. Notwithstanding the reference to annual plant in its name, perennial bio-types ...

''), perennial ryegrass (''

Lolium perenne ''Lolium perenne'', common name perennial ryegrass, English ryegrass, winter ryegrass, or ray grass, is a grass from the family Poaceae. It is native to Europe, Asia and northern Africa, but is widely cultivated and naturalised around the world. ...

'') and creeping bentgrass (''

Agrostis stolonifera ''Agrostis stolonifera'' (creeping bentgrass, creeping bent, fiorin, spreading bent or carpet bentgrass) is a perennial grass species in the family Poaceae. Description ''Agrostis stolonifera'' is stoloniferous and may form mats or tufts. The p ...

'') are more susceptible. In the fall, ''M.nivale'' infection begins as small, orange to red-brown spots, circular and only a few centimeters in diameter. During the winter and into the spring seasons, well-defined, clustered, circular patches 10-20 cm in diameter, of

necrotic Necrosis () is a form of cell injury which results in the premature death of cells in living tissue by autolysis. Necrosis is caused by factors external to the cell or tissue, such as infection, or trauma which result in the unregulated dige ...

leaf tissues form on mown turf. ''Microdochium nivale'' is mostly seen on grasses mown at heights of three inches or greater. On taller grass, patches often lack a circular pattern that is seen in shorter mown grass. Pink snow mold patches usually follow

drainage Drainage is the natural or artificial removal of a surface's water and sub-surface water from an area with excess of water. The internal drainage of most agricultural soils is good enough to prevent severe waterlogging (anaerobic condition ...

patterns since

conidia A conidium ( ; ), sometimes termed an asexual chlamydospore or chlamydoconidium (), is an asexual, non- motile spore of a fungus. The word ''conidium'' comes from the Ancient Greek word for dust, ('). They are also called mitospores due to t ...

spore In biology, a spore is a unit of sexual or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores form part of the life cycles of many plants, algae, ...

s are readily dislodged and transported by

rain Rain is water droplets that have condensed from atmospheric water vapor and then fall under gravity. Rain is a major component of the water cycle and is responsible for depositing most of the fresh water on the Earth. It provides water f ...

fall and water flowage. Under prolonged cool and wet conditions, white-pink

can be observed along the circumference of diseased patches.

Disease cycle

''M. nivale'' begins by oversummering (surviving the summer) in thatch or soil as

haploid Ploidy () is the number of complete sets of chromosomes in a cell, and hence the number of possible alleles for autosomal and pseudoautosomal genes. Sets of chromosomes refer to the number of maternal and paternal chromosome copies, respective ...

mycelium or

spores In biology, a spore is a unit of sexual or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores form part of the life cycles of many plants, algae, ...

. When cool, wet weather arrives in the fall or winter the

grows from thatch or soil and infects leaves. These environmental conditions also favor the development of asexual spores called

on conidiophores. These conidia infect leaf sheaths and blades near the soil. Wind and surface water will help aid in the spread of this disease as it will allow for the spores to contact near by healthy plant. The disease becomes very severe if allowed to spread from the leaf blades to the

crown A crown is a traditional form of head adornment, or hat, worn by monarchs as a symbol of their power and dignity. A crown is often, by extension, a symbol of the monarch's government or items endorsed by it. The word itself is used, partic ...

of the plant. This usually only happens under extreme circumstances, particularly if

snow Snow comprises individual ice crystals that grow while suspended in the atmosphere—usually within clouds—and then fall, accumulating on the ground where they undergo further changes. It consists of frozen crystalline water throughou ...

fall covers unfrozen ground.

Environment

''Microdochium nivale'' becomes problematic when turf experiences lengthy periods of cool, wet weather typical of fall or spring and into early summer in the

Northern Hemisphere The Northern Hemisphere is the half of Earth that is north of the Equator. For other planets in the Solar System, north is defined as being in the same celestial hemisphere relative to the invariable plane of the solar system as Earth's Nort ...

. The name is somewhat confusing because the presence of snow is not necessary for this pathogen to develop. The disease can thrive under snow cover, however, if it falls on unfrozen soil with thriving turf. In general this disease tends to develop proficiently when grass is growing at a slower than normal rate. Limiting fall

nitrogen Nitrogen is the chemical element with the symbol N and atomic number 7. Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. It is a common element in the universe, estimated at se ...

applications in an attempt to decrease the growth of grass and promote

dormancy Dormancy is a period in an organism's life cycle when growth, development, and (in animals) physical activity are temporarily stopped. This minimizes metabolic activity and therefore helps an organism to conserve energy. Dormancy tends to be c ...

can help decrease the incidence of Pink Snow Mold. In regions of high humidity and temperatures ranging between 32 and 46 degrees Fahrenheit or 0 to 8 degrees Celsius, pink snow mold will develop rapidly.

Management

There are a number of different ways to manage diseases including cultural, chemical, and biological controls. Some of these controls are more effective than others, however, the best approach to a managing any disease, including Microdochium Patch, is an integrated approach called

Integrated Pest Management Integrated pest management (IPM), also known as integrated pest control (IPC) is a broad-based approach that integrates both chemical and non-chemical practices for economic control of pests. IPM aims to suppress pest populations below the eco ...

or IPM. IPM uses a combination of chemical, cultural and biological controls to reduce spending on pesticides and to decrease

pesticide resistance Pesticide resistance describes the decreased susceptibility of a pest population to a pesticide that was previously effective at controlling the pest. Pest species evolve pesticide resistance via natural selection: the most resistant specimens su ...

. The following are some of the most important cultural controls used in managing Microdochium Patch.

Cultural controls

Raising the mowing height is an easy way to reduce stress on a turfgrass plant and make the plant less susceptible to attack by disease, but there is a fine line. Turf mowed, less than and above makes the plant more susceptible to disease. Managing the moisture available to the plant is another way to help reduce the incidence of disease. The pathogen that causes Microdochium Patch requires and thrives in moist, cool conditions, therefore making sure that you aren't overwatering the turf when conditions are right for infection is very important. Giving the plant only enough water for normal plant function is the best way to ensure disease pressure is reduced as much as possible. Also, starving the turf of moisture can be damaging as this increases susceptibility to infection. Managing the amount of

available to the plant is another key to decreasing incidence of this disease. Avoiding excess fall nitrogen application will greatly reduce disease pressure of ''Microdochium nivale''. On top of that excess nitrogen available to plant produces rapid growth of above ground tissue. This tissue often has thin

cell wall A cell wall is a structural layer surrounding some types of cells, just outside the cell membrane. It can be tough, flexible, and sometimes rigid. It provides the cell with both structural support and protection, and also acts as a filtering mec ...

s and is prone to attack by disease. Managing thatch and

soil drainage Drainage is the natural or artificial removal of a surface's water and sub-surface water from an area with excess of water. The internal drainage of most agricultural soils is good enough to prevent severe waterlogging (anaerobic condition ...

are two other important ways of controlling this disease as both of these affect the amount of moisture that is available to create a favorable environment to the disease, giving the plant only enough water for normal plant function is the best way to ensure disease pressure is reduced as much as possible. Despite the fact that the above cultural controls cannot completely control Microdochium Patch, when they are all used to reduce disease pressure, they can have a noticeable impact and will help to reduce the amount of chemical control that is required.

Chemical controls

Chemical controls (i.e. the use of fungicides) to specifically control turf grass diseases have been around since 1891. Over the years better controls have been developed, all of which tend to be less toxic to animals and the environment when used properly. There is a wide variety of chemical groups that are labeled for control of Microdochium Patch. They include, but are not limited to the methyl

benzimidazole Benzimidazole is a heterocyclic aromatic organic compound. This bicyclic compound may be viewed as fused rings of the aromatic compounds benzene and imidazole. It is a colorless solid. Preparation Benzimidazole is produced by condensation of o ...

carbamates In organic chemistry, a carbamate is a category of organic compounds with the general formula and structure , which are formally derived from carbamic acid (). The term includes organic compounds (e.g., the ester ethyl carbamate), formally o ...

(MBCs) such as thiophanate methyl, the dicarboximides such as

iprodione Iprodione is a hydantoin fungicide and nematicide. Application Iprodione is used on crops affected by Botrytis bunch rot, Brown rot, Sclerotinia and other fungal diseases in plants. It is currently applied in a variety of crops: fruit, vegetable ...

and

vinclozolin Vinclozolin (trade names Ronilan, Curalan, Vorlan, Touche) is a common Dicarboximide fungicides, dicarboximide fungicide used to control diseases, such as blights, rots and molds in vineyards, and on fruits and vegetables such as raspberries, let ...

, the DMIs such as

fenarimol Fenarimol, sold under the tradenames Bloc, Rimidin and Rubigan, is a fungicide which acts against rusts, blackspot and mildew fungi. It is used on ornamental plants, trees, lawns, tomatoes, peppers, eggplants, cucumbers and melons. It is mainly ...

and

propiconazole Propiconazole is a triazole fungicide, also known as a DMI, or demethylation inhibiting fungicide due to its binding with and inhibiting the 14-alpha demethylase enzyme from demethylating a precursor to ergosterol. Without this demethylation ste ...

, the QoIs such as

azoxystrobin Azoxystrobin is the ISO common name for an organic compound that is used as a fungicide. It is a broad spectrum systemic active ingredient widely used in agriculture to protect crops from fungal diseases. It was first marketed in 1996 using the ...

pyraclostrobin Pyraclostrobin is a quinone outside inhibitor ( QI)-type fungicide used in agriculture. Among the QIs, it lies within the strobilurin chemical class. Use Pyraclostrobin is used to protect ''Fragaria'', ''Rubus idaeus'', ''Vaccinium corymbosum'', ...

, and trifloxystrobin, the phenylpyrroles such as fludioxonil, certain

aromatic hydrocarbon Aromatic compounds, also known as "mono- and polycyclic aromatic hydrocarbons", are organic compounds containing one or more aromatic rings. The parent member of aromatic compounds is benzene. The word "aromatic" originates from the past groupin ...

s such as PCNB, and the cholronitriles such as

chlorothalonil Chlorothalonil (2,4,5,6-tetrachloroisophthalonitrile) is an organic compound mainly used as a broad spectrum, nonsystemic fungicide, with other uses as a wood protectant, pesticide, acaricide, and to control mold, mildew, bacteria, algae. Ch ...

. ick Christians.2007. Fundamentals of Turfgrass Management. Wiley and Sons.Hoboken, NJ/ref> These chemical classes should be rotated so that selection pressure on the disease in limited as to avoid resistant strains of this disease. The applicator should read and follow all label rates and directions. Breaking these directions and misuse of any labeled product is breaking the law. Remember that the label is the law. The best way to control Microdochium Patch especially going into winter is to use a three way spray right before the first snow fall. A combination of a dicarboximides such as

, a chloronitrile such as chlorothalonil, and a DMI such as

will give sufficient control over the span of an average winter.

Importance

Microdochium Patch is a significant problem in the turfgrass management industry. Sports fields,

sod Sod, also known as turf, is the upper layer of soil with the grass growing on it that is often harvested into rolls. In Australian and British English, sod is more commonly known as ''turf'', and the word "sod" is limited mainly to agricult ...

farms and home

lawn A lawn is an area of soil-covered land planted with grasses and other durable plants such as clover which are maintained at a short height with a lawnmower (or sometimes grazing animals) and used for aesthetic and recreational purposes. ...

s and

golf course A golf course is the grounds on which the sport of golf is played. It consists of a series of holes, each consisting of a tee box, a fairway, the rough and other hazards, and a green with a cylindrical hole in the ground, known as a "cup". ...

s can all be damaged by this the disease. The pathogen can be found in the Northern United States and all the way up into Canada, meaning that there is a large area where this pathogen can cause serious disease. The highest incidence of this disease in these areas occurs on golf courses due to the highly managed areas of susceptible turfgrass species such as Creeping Bentgrass (''

'') and Annual Bluegrass (''

''). It is of particular concern because turf on golf courses is considered a high value crop. Diseases such a Microdochium Patch lower the value of the crop by decreasing its aesthetic value, affecting the playability, and decreasing the overall health of the turf. Because golf course budgets are often quite tight, the reduction of fungicide applications required in a season for snow mold will result in more money elsewhere in the budget. Being that the fungicide budget can be 10% of the maintenance budget, reductions in the use of fungicides can cause a significant increase in the amount of money to do other things. On top of that, reducing fungicide inputs helps keep the environment safe and reduces the chances of

fungicide resistance Fungicides are biocidal chemical compounds or biological organisms used to kill parasitic fungi or their spores. A fungistatic inhibits their growth. Fungi can cause serious damage in agriculture, resulting in critical losses of yield, quality, ...

development.

References

External links

More Information on Lawn Care and Fusarium Patch

Additional Information on Microdochium Patch

Additional Information on Microdochium Patch

Additional Information on Management of Microdochium Patch

Additional Information on Microdochium Patch

Turfgrass disease profile
Index Fungorum

USDA ARS Fungal Database
{{DEFAULTSORT:Fusarium Patch Xylariales Fungal plant pathogens and diseases Turfgrass diseases *Fusarium patch fi:Lumihome