''Colletotrichum coccodes'' is a

plant pathogen Plant diseases are diseases in plants caused by pathogens (infectious organisms) and environmental conditions (physiological factors). Organisms that cause infectious disease include fungi, oomycetes, bacteria, viruses, viroids, virus-like orga ...

, which causes

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 ...

tomato The tomato (, ), ''Solanum lycopersicum'', is a plant whose fruit is an edible Berry (botany), berry that is eaten as a vegetable. The tomato is a member of the nightshade family that includes tobacco, potato, and chili peppers. It originate ...

and black dot disease of

potato The potato () is a starchy tuberous vegetable native to the Americas that is consumed as a staple food in many parts of the world. Potatoes are underground stem tubers of the plant ''Solanum tuberosum'', a perennial in the nightshade famil ...

. Fungi survive on crop debris and disease emergence is favored by warm temperatures and wet weather.

Hosts and symptoms

''C. coccodes'' is known for infecting

and

, and is primarily a

pathogen In biology, a pathogen (, "suffering", "passion" and , "producer of"), in the oldest and broadest sense, is any organism or agent that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a Germ theory of d ...

of Solanaceous plants more generally. Heilmann ''et al.'', 2006 characterizes genetic varieties and their associations with particular potato

host A host is a person responsible for guests at an event or for providing hospitality during it. Host may also refer to: Places * Host, Pennsylvania, a village in Berks County * Host Island, in the Wilhelm Archipelago, Antarctica People * ...

s. Buddie ''et al.'', 1999, finds

strawberry The garden strawberry (or simply strawberry; ''Fragaria × ananassa'') is a widely grown Hybrid (biology), hybrid plant cultivated worldwide for its fruit. The genus ''Fragaria'', the strawberries, is in the rose family, Rosaceae. The fruit ...

is also a host. ''C. coccodes'' has a large

host range In biology and medicine, a host is a larger organism that harbours a smaller organism; whether a parasite, parasitic, a mutualism (biology), mutualistic, or a commensalism, commensalist ''guest'' (symbiont). The guest is typically provided with ...

beyond those including some

Cucurbitaceae The Cucurbitaceae (), also called cucurbits or the gourd family, are a plant family (biology), family consisting of about 965 species in 101 genera.

Fabaceae Fabaceae () or Leguminosae,International Code of Nomen ...

, and

Solanaceae Solanaceae (), commonly known as the nightshades, is a family of flowering plants in the order Solanales. It contains approximately 2,700 species, several of which are used as agricultural crops, medicinal plants, and ornamental plants. Many me ...

. ''C. coccodes'' can cause lesions, twisted leaves, and a bleached color on onion. On tomato, can see that there are sunken in dark spots. As the disease continues to develop can begin to see spots that are rotting. The pathogen can infect both green and ripe fruit; spots are not evident on green right away, but over time they develop. Symptoms are most common on the fruit, but they may also appear on the stem, leaves, and roots. In potato, ''C. coccodes'' is characterized by silvery lesions on the tuber surface which result in a deterioration in skin quality. In addition to causing tuber blemish symptoms, ''C. coccodes'' also causes symptoms on stems and foliage, which result in crop losses, and is implicated as a factor in the potato early dying disease complex. In the past the pathogen was not regarded as an issue, but it has become more prevalent.

Disease cycle

''Colletotrichum coccodes'' can survive the winter as hard, melanized structures called sclerotia. The pathogen may also survive in debris as threadlike strands called

hypha A hypha (; ) is a long, branching, filamentous structure of a fungus, oomycete, or actinobacterium. In most fungi, hyphae are the main mode of vegetative growth, and are collectively called a mycelium. Structure A hypha consists of one o ...

e. In late spring the lower leaves and fruit may become infected by germinating

sclerotia A sclerotium (; : sclerotia () is a compact mass of hardened fungal mycelium containing food reserves. One role of sclerotia is to survive environmental extremes. In some higher fungi such as ergot, sclerotia become detached and remain dormant u ...

and

spore In biology, a spore is a unit of sexual reproduction, sexual (in fungi) or asexual reproduction that may be adapted for biological dispersal, dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores fo ...

s in the soil debris. Infections of the lower leaves of tomato plants are important sources of spores for secondary infections throughout the growing season. Senescent leaves with early blight infections and leaves with flea beetle injury are especially important spore sources because the fungus can colonize and produce new spores in these wounded areas. The growth of ''C. coccodes'' is most rapid at , although the fungus can cause infections over a wide range of temperatures between . Wet weather promotes disease development, and splashing water in the form of rain or irrigation favors the spread of the disease. The pathogen also produces an acervulus which is full of

conidia A conidium ( ; : conidia), sometimes termed an asexual chlamydospore or chlamydoconidium (: chlamydoconidia), is an asexual, non- motile spore of a fungus. The word ''conidium'' comes from the Ancient Greek word for dust, ('). They are also ...

that help to spread the infection.

Management

Plant crops on well drained soils, use 3- or 4- year

crop rotation Crop rotation is the practice of growing a series of different types of crops in the same area across a sequence of growing seasons. This practice reduces the reliance of crops on one set of nutrients, pest and weed pressure, along with the pro ...

s with plants which are not hosts, and resistant plants. Sanitation can also be important to reduce the spread of inoculum and clean seed should be planted. Soil fumigants may also be used although they may not be as economic as the other methods of control. Irrigation is to be avoided when fruit begins to ripen to avoid the splashing of spores, it is also recommended to rotate with a nonsolanaceous crop every other year.

References

External links

''Colletotrichum coccodes''
Gilat Research Center
Horticulture Talk: ''Battling Tomato Anthracnose''
{{Authority control coccodes Potato diseases Tomato diseases Fungi described in 1833 Taxa named by Karl Friedrich Wilhelm Wallroth Fungus species