Pythium graminicola
| Pythium graminicola | ||||||||||||
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| Pythium graminicola | ||||||||||||
| Subraman., (1928) |
Pythium graminicola is a phyto-pathogen belonging to the Pythiaceae familywithin the group of egg fungi . It infects grains and other agricultural crops.
Hosts and Symptoms
Pythium graminicola has a wide range of hosts that include ostrich grasses , turmeric , cotton , barley , wheat , rice , bean , peas, and sugar cane . Pythium graminicola particularly attacks grassy species such as cereals . As with many by Pythium the most common symptom is an infection with diseases caused TYPES Pythium graminicola a root or seed rot , which can cause death of the whole plant. However, P. graminicola can also infect parts of plants above ground, causing stem rot in maize , wilting of the base in beans, leaf bleaching in grasses, and root rot in rice, sugar cane and maize. The diagnosis of an infection with Pythium graminicola can be made by observing the symptoms described and the presence of typical fungal structures such as sporangia .
Life cycle
The life cycle of Pythium graminicola corresponds to that of all soil-borne Pythium species. In the state of sexual reproduction, an antheridium and an oogon combine to form an oospore . An oospore has a thick cell wall and can survive in unfavorable conditions such as winter either in the soil or in plant remains. These oospores are the primary inoculum ; they remain in dormancy for up to ten years and germinate under favorable conditions. Oospores can be spread by wind or - if they are in the soil - trigger a systemic infection of the host seedlings. After infection by oospores, sporangia are formed in the host plants, the asexual phase of Pythium graminicola , which is the secondary inoculum; this makes the life cycle polycyclic. The sporangia can also be spread by the wind and form zoospores that can trigger an infection. The zoospores are able to swim short distances in the water with the help of flagella and thus reach the host plants. They attach to the tissue surface of the hosts and germinate into the plant by forming hyphae . P. graminicola spreads very rapidly in the host tissue. Penetration is rapid and the host's cell walls do not form a significant barrier to infection.
treatment
There are currently several approaches to control Pythium graminicola , including chemical and biological control , the exploitation of resistance in the host plants and cultivation measures. Chemical control uses specific pesticides such as benomyl , captafol , captan , carboxin , metalaxyl , propamocarb hydrochloride and etridiazole to kill oospores that have survived in the soil. Seeds can also be dipped in chemicals to protect them from root rot and prevent wilting. Biological pest control involves the use of microorganisms that protect the plant roots by releasing metabolic products that inhibit fungus or by competing with pathogens for nutrients. Some agents for biological pest control of Pythium root rot are already commercially available, obtained from isolates of Trichoderma and Gliocladium species, which are antagonists of Pythium -induced soil-borne diseases. Genetic resistance is achieved by choosing plant varieties that are not sensitive to Pythium graminicola . Cultivation measures are a broad category of methods that go beyond the measures mentioned above. This includes avoiding cultivation under conditions that encourage the pathogens to thrive. Another example is the use of compost with a special composition, e.g. B. with brewery residues, sewage sludge from Endicott (New York) and manure from some animal species to suppress wilting and root rot.
Individual evidence
- ^ Weidong Chen, Jeffrey W. Hoy: Molecular and morphological comparison of Pythium arrhenomanes and P. graminicola . In: Mycological Research . 97, No. 11, November 1, 1993, ISSN 0953-7562 , pp. 1371-1378. doi : 10.1016 / S0953-7562 (09) 80172-X .
- ↑ seedling blight of grasses (Pythium graminicola) . Retrieved December 13, 2017.
- ^ WE McKeen: Growth of Pythium graminicola in barley roots . In: Canadian Journal of Botany . 55, No. 1, 1977, pp. 44-47. doi : 10.1139 / b77-010 .
- ↑ a b c John Rusagara Nzungize, François Lyumugabe, Jean-Pierre Busogoro, Jean-Pierre Baudoin: Pythium root rot of common bean: biology and control methods. A review . In: BASE . January 2012, ISSN 1370-6233 .
- ↑ CM Craft: Microbial Properties of Composts That Suppress Damping-Off and Root Rot of Creeping Bentgrass Caused by Pythium graminicola . In: Appl. Environ. Microbiol. . 62, No. 5, 1996, pp. 1550-1557. PMC 1388845 (free full text).