Wheat stone brandy

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Wheat stone brandy
Tilletia caries (DC.) Tul.  & C. Tul..JPG

Wheat stone brandy ( Tilletia caries )

Systematics
Subdivision : Ustilaginomycotina
Class : Ustilaginomycetes
Order : Smut fungus (Ustilaginales)
Family : Tilletiaceae
Genre : Tilletia
Type : Wheat stone brandy
Scientific name
Tilletia caries
( DC. ) Tul. & C. Tul.

The bunt of wheat ( Tilletia caries ) is a parasitic fungus that wheat attacks. Symptoms of infestation show up around the flower. Later, burn hips appear in the fruit heads, which, in contrast to normal grains, are black in color due to the fungal spores they contain. This results in an immediate loss of income. The wheat is unsuitable for grinding and, in extreme cases, as feed.

history

Already in antiquity, Theophrastus of Eresus (3rd century BC) and later Pliny the Elder (1st century AD) mentioned the burning of the ear in the 18th book of his Naturalis historia . Although it was recognized even then that the health of cultivated plants can be promoted by dressing the seeds, these experiences were lost with the decline of ancient culture.

At the end of the Middle Ages, the wheat stone fire was one of the main causes of yield losses and poor harvests, and thus triggered famine among the population. The toxicity of the spores ( trimethylamine ) caused diseases in humans and animals, often with fatal consequences.

It was not until the middle of the 19th century that the connections between plant disease and the quality of the seeds were discovered and ways of combating fire diseases were explored. With the introduction of the washing of grain, warm and hot water pickling, but above all through the treatment of seeds with mercury , the spread of the stone fire was put to a lasting halt.

In the 1970s and 1980s, the toxic mercury dressings were replaced by new, more nontoxic and more environmentally friendly chemical-synthetic seed dressings and finally banned in European countries.

Due to the common use of seed dressing in modern agriculture, crop losses due to stone fire are only of major importance in developing countries today. However, the use of seed dressing is not allowed in organic agriculture , which is why its spread in Europe is increasing again due to the increasing expansion of organic farming.

Stone fire as a biological weapon

During the Cold War , research was carried out into using fungal spores of the genus Tilletia , including wheat stone brandy, as a biological crop destruction agent.

The Iraq should the use of Tilletia in the Iran-Iraq war have considered.

features

The ears of the host are filled with sori , they are partially covered by the husks . They are four to eight millimeters long with a diameter similar to that of an uninfected ear. The powdery, reddish brown to blackish and smelly spore mass consists of spores and sterile cells. The latter are spherical, hyaline , thin-walled, smooth and measure 10–20 µm (mostly around 13 µm). The spores do not have a shell and are spherical to egg-shaped, light to reddish brown and measure 14–23 µm in diameter (about 18 µm on average). Their walls are reticulated with a depth of 0.5–1.5 µm and less than 3 µm wide.

Species delimitation

A correct determination is only possible with the help of microscopic examination of the spores.

From the similar Tilletia laevis (syn. Tilletia foetida ), which also occurs on wheat , the species differs from the morphology of the teliospores : They are ornamented in a reticulate manner in wheat stone brandy, but smooth in Tilletia laevis .

In Tilletia controversa (dwarf stone brandy), on the other hand, the network of ridges covering the surface of the spores is significantly higher.

Damage

Even the cotyledons could have small chlorotic spots that are easy to miss. The color of the ears changes from blue-green to dirty gray. You can smell the wheat stone brandy from 10,000 spores per grain, which cannot be visually recognized. The ears of corn are often spread apart and contain coals that stink of fish. The spore mass contained there is initially greasy black and later dry. The length of the plant is shortened somewhat, but not as much as in the dwarf stone brandy . In return, the stalks of infested plants stay green longer. After threshing, the spores stick to the outside of the seed, especially the beard.

biology

germinating spores

The bunt of wheat comes to species of the genera next to the wheat Aegilops , Agropyron , brome , couch grass , barley , bluegrasses , rye , Sitanion , wheat and triticale ago. The spores are viable in the fire hips for decades. After sowing, they germinate at the same time as the grains. The grain seedling can be infected up to a growth size of two centimeters. Optimal infection conditions are between five and ten degrees Celsius. A low level of moisture is sufficient on clay soil, sandy soil must be moderately moist and bog soil needs a high level of moisture of 20 to 60 percent.

Countermeasures

To prevent wheat stone brandy, seeds that are as pure as possible must first be used. First of all, it is important to ensure that the threshing is clean. If necessary, you can use a seed brushing machine, dress the seeds with hot water or use pesticides based on Pseudomonas chlororaphis . An early winter wheat sowing and a late spring wheat sowing as well as seeds with high growing power are helpful.

Systematics

The wheat stone brandy has a number of synonyms. The best known is Tilletia triticis .

Web links

Commons : Tilletia caries  - collection of images, videos and audio files

Individual evidence

  1. Dr. agr. habil. Hartmut Spieß, Bernd Ewald, Evelyne Stoll: Weizensteinbrand - A brochure as part of the “Organic Farming Action Plan Luxembourg”. Institut fir Biologesch Landwirtschaft an Agrarkultur Lëtzebuerg (IBLA) asbl; Bio-Lëtzebuerg - Association fir Bio-Landwirtschaft Lëtzebuerg asbl, July 11, 2016, accessed on October 10, 2017 .
  2. OF Mamluk: Bunts and smuts of wheat in North Africa and the Near East . In: Euphytica . tape 100 , no. 1-3 , April 1, 1998, ISSN  0014-2336 , pp. 45-50 , doi : 10.1023 / A: 1018343603827 .
  3. www.proplanta.de: Stone fire and dwarf stone fire are spreading . In: proplanta.de . April 1, 2012 ( proplanta.de [accessed October 10, 2017]).
  4. Malcom Dando; Paul Rogers; Simon Whitby: Bio-weapons that destroy the harvest . Ed .: Spectrum of Science. Edition 10/1999 , page 72 ( Spektrum.de [accessed October 10, 2017]).
  5. a b Mordue, JEM; Waller, JM 1981. 719: 1-2: Tilletia caries. CMI Descriptions of Pathogenic Fungi and Bacteria. In: IMA Fungus . tape 719 , 1981, pp. 1–2 ( accessed April 24, 2015 from Mycobank ).
  6. a b AgroAtlas: Interactive Agricultural Ecological Atlas of Russia and Neighboring countries: Tilletia caries (DC.) Tul., Tilletia laevis Kuehn - Common bunt (Stinking smut, Bunt smut, Covered smut) accessed on April 25, 2015 .
  7. ^ Stone brandy and dwarf stone brandy of wheat. Bavarian State Research Center for Agriculture (LfL), December 2012, accessed on October 15, 2017 .
  8. Institute fir Biologesch agriculture to agriculture, Luxemburg: The bunt. ( Memento from April 5, 2016 in the Internet Archive ) (PDF file; 4.5 MB) from March 2015
  9. a b c Oekolandbau.de Wheat stone brandy (Tilletia caries) , last update: July 26, 2010.
  10. RFN Langdon, JF Kdlmorgen, J. Walker: The nomenclature of the smuts of wheat, barley, oats, rye and certain grasses . In: Australian Plant Pathology Society Newsletter . tape 5 , no. 4 , 1976, p. 52-54 , doi : 10.1071 / APP9760052 .