''Colletotrichum cereale'' is a plant disease (

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 from th ...

) that has been found to cause crown rot

anthracnose A plant canker is a small area of dead tissue, which grows slowly, often over years. Some cankers are of only minor consequence, but others are ultimately lethal and therefore can have major economic implications for agriculture and horticultur ...

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 ...

most commonly occurring on

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". Th ...

s (NC State 2012). Anthracnose can occur as both a foliar blight and basal rot (Penn State 2010). This disease attacks the

crowns 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 plants, which is different than other anthracnose diseases. Anthracnose of turfgrass can be a foliar disease or in this case a basal rot of the lower portion of the plant. It attacks different species of turfgrass throughout the world most commonly

annual bluegrass ''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 ...

and

creeping bentgrass ''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 ...

(Crouch, Clarke 2012).

Hosts and symptoms

Symptoms

''Colletotrichum cereale'' affects at least thirteen warm and cool season turfgrass species that are susceptible hosts. The two most common species that are affected are annual bluegrass and creeping bentgrass when they are grown in a managed setting such as a golf course. Anthracnose happens when the fungus infects the leaf sheaths (NC State 2012). Symptoms can include tissue color appearing brown or black; leaf blades appear orange or yellow (no lesions), and patchy appearance to turf on lawns and golf courses. Patches of the disease can range from different sizes either small irregular patches or giant large-scale areas (Settle, Martinez-Espinosa, Burpee 2006).

Signs

Signs of ''Colletotrichum'' include spore-bearing structures called

acervuli An acervulus (pl. acervuli) is a small asexual fruiting body that erupts through the epidermis of host plants parasitised by mitosporic fungi of the form order Melanconiales ( Deuteromycota, Coelomycetes). It has the form of a small cushion at th ...

in the center of leaf spots or brown/dead leaves being covered in acervuli. The acervuli are fruiting structures that will eventually produce asexual spores called

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 the ...

. The most common sign that can be attributed to this disease is tufts of black

setae In biology, setae (singular seta ; from the Latin word for "bristle") are any of a number of different bristle- or hair-like structures on living organisms. Animal setae Protostomes Annelid setae are stiff bristles present on the body. Th ...

on the plant tissue, most commonly on dead tissue (Settle, Martinez-Espinosa, Burpee 2006). The disease is known to affect the host the most severely when the turf is thin or if there is very little of a certain species, when the turf is cut at low mowing heights, and when fertility is low (Crouch, Clarke 2012). It is able to single out and target turf species that are small in number compared to the dominant species. This can cause the patchy appearance in mixed turf settings. Other severe outbreaks have been known to selectively kill bluegrass when it is invading on a creeping bentgrass putting green (Settle, Martinez-Espinosa, Burpee 2006).

Environment

''Colletotrichum'' can occur all over the world infecting annual bluegrass. It is most commonly found on bentgrass in the eastern and southeastern United States (Michigan State 2016). This disease thrives in high moisture and can be found appearing after periods of heavy rainfall or excessive irrigation. The disease can occur in both cool and warm temperatures, which makes it a problem with it having no preferred temperature range. However, it has been found that the most common temperatures that the disease can exist in are warm, moist areas with temperatures around 78 degrees Fahrenheit or higher (Trugreen 2016). Moisture is the main factor that affects the disease. Other factors that contribute to the disease include root zone compaction,

thatch Thatching is the craft of building a roof with dry vegetation such as straw, water reed, sedge (''Cladium mariscus''), rushes, heather, or palm branches, layering the vegetation so as to shed water away from the inner roof. Since the bulk of ...

accumulation, low fertility, low mowing height, and insect

infestation Infestation is the state of being invaded or overrun by pests or parasites. It can also refer to the actual organisms living on or within a host. Terminology In general, the term "infestation" refers to parasitic diseases caused by animals su ...

Disease management practices

Cultural control

Cultural practices that can reduce or control the spread of the disease include core aerification, dethatching, topdressing, light weight equipment to prevent compaction such as mowers, higher mowing heights, increased nitrogen, avoiding nighttime irrigation, and monitored irrigation to prevent long periods of leaf wetness (Settle, Martinez-Espinosa, Burpee 2006). These practices should be put in place before symptoms develop because some of them cause wounds that can increase the spread of the disease (Trugreen 2016).

Chemical control

Chemical management practices include the uses of

fungicide 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, ...

s. There are different types of fungicides including contact, penetrant, and systemic. Each of these is able to provide preventative and curative activity, however preventative is usually more effective at controlling the disease (Penn State 2010). Preventative is before infection and curative is after the infection is observed. ''Colletotrichum cereale'' has been found to have developed resistance to some kinds of fungicides in certain areas of the US (Settle, Martinez-Espinosa, Burpee 2006). Selecting the right fungicide and choosing when to apply it is very important in order for it to be effective against the disease.

Biological control

Biological control has a few options although studies are still being done to find an effective approach. Surface hydrophobicity has been found to induce spore germination, so the approach is to select annual bluegrass and creeping bentgrass with a non-waxy cuticle to try and interfere with germination of the conidia (Settle, Martinez-Espinosa, Burpee 2006). There are no known resistant cultivars of creeping bentgrass or annual bluegrass (Michigan State 2016).

References

* College of Agricultural Sciences. "Managing Turfgrass Diseases." ''Penn State Extension''. Penn State University, 2010. Web. 6 Dec. 2016. http://extension.psu.edu/publications/agrs-101 * Crouch, Jo Anne, and Bruce B. Clarke. "Biology and Pathology of Turfgrass Anthracnose." ''USGA Turfgrass and Environmental Research''. USGA, 1 May 2012. Web. 6 Dec. 2016. http://usgatero.msu.edu/v11/n05.pdf * Michigan State University. "Crown Rot Anthracnose — Colletotrichum Cereale." ''MSU Turf Diseases''. Michigan State University, 2016. Web. 06 Dec. 2016. http://www.msuturfdiseases.net/details/_/crown_rot_anthracnose_3/ * North Carolina State University. "Turf Disease Detail For Anthracnose (Colletotrichum Cereale)." ''Turf Disease Detail For Anthracnose (Colletotrichum Cereale)''. North Carolina State University, 2012. Web. 06 Dec. 2016. http://turfdiseaseid.ncsu.edu/diseasedetail.aspx?disease=COLGR * Settle, Derek M., Alfredo D. Martinez-Espinosa, and Lee L. Burpee. "Anthracnose of Turfgrass." ''American Phytopathological Society''. The American Phytopathological Society, 2006. Web. 06 Dec. 2016. https://web.archive.org/web/20161122040225/https://www.apsnet.org/edcenter/intropp/lessons/fungi/ascomycetes/Pages/Anthracnoseofturfgrass.aspx * Trugreen. "Lawn Disease: Anthracnose." ''Scotts Lawn Service''. Trugreen, 2016. Web. 06 Dec. 2016. https://web.archive.org/web/20161221005720/https://www.scottslawnservice.com/sls/templates/index.jsp?pageUrl=slsanthracnose {{Taxonbar, from=Q5147069 cereale Fungal plant pathogens and diseases Cereal diseases