Kusymbaeva S.K.

KSU named A.Baitursynov , Kazakhstan

Systematic position, species composition and morphological features of fungi of the genus SEPTORIA.

Septoria crops causing fungi of the genus Septoria, belonging to the class of modern taxonomy Deuteromycetes, order Sphaeropsidaeles (Pycnidiaeles), family Sphaeopsidacea.

The hallmark of this genus is a reproduction by conidia (piknospor) formed within well-defined fruiting bodies - pycnidia.

Septoria pycnidia formed under the epidermis. They are mainly spherical in shape and dark in color, covered with leathery shell, have a flat circular opening (stoma) of various sizes, most often located on both sides of the scattered or concentrated in the center of the spot group.

Conidia usually elongated, straight or curved, blunt or sharp ends. Their size ranges from 13-125 × 0,7 - 4,5 microns. Known conidia form: filiform (52 %) of cylindrical (20 %), spindle-shaped (7%), clavate (1%) [1].

In the cycle of developing certain types of Septoria observed mikrokonidialnaya stage. Microspores may be within normal pycnidia together with normal spores, or in smaller pycnidia. It can attack the plants and play a role in the spread of pathogens over long distances [2].

For some types of Septoria known perfect stage - marsupial sporulation, it is found in the genera Mycosphaerella (family Mycospharellaceae, order Dothideales) and Leptosphaerella, (family Pleosporaceae, order Pleosporales), belonging to the class Ascomycetes, subclass Loculoascomycetidae. Bags are formed in the cavities of the stroma - loci called Pseudothecia.

The basis of determining the species of fungi of the genus Septoria laid shape, structure and size of pycnidia and conidia, although these symptoms are quite variable. Most species are constant properties of the width and shape of conidia. The genus Septoria conidia are known elongated while their length is often ten times larger than the width. Therefore, the difference in width of 1 mm is quite significant for the general outlines and shapes. According D.N.Teterevnikovoy - Baboyan (1987), namely the width and structure of all conidia (rounded, blunt, pointed, etc.) define their common habit.

Wheat is the leading cereal crop by number izvetyh it species Septoria. According to the literature found 16 names of pathogens.

The most well-known types of wheat are Septoria nodorum and Septoria tritici.

Septoria nodorum Berk. Berkely was first described in 1845 in England to wheat stem nodes called Depazea nodorum Berk. In 1850, the author changed the name to Septoria nodorum Berk.

This view is widespread, it occurs most often in cool wet Oblasov in rainy years, but may cause harm in the drylands. This species is dominant in much of Europe, especially in Germany , UK, USA, Brazil, North Africa, Russia , and also in our country [3].

S. nodorum affects all organs of wheat land in all phases of the growing season, but usually prevails on adult plants, as traditional agent flag - leaf and ear. Fungus on the leaves usually form a dark brown spots with light middle, on the ears - dark purple spots.

Pycnidia S. nodorum rather small (48-210 microns in diameter), are under the epidermis, stomata size of 20-40 microns. Piknospor size 15-35 microns. At the end of the growing season in conjunction with normal pycnidia spores formed microspores.

Harmfulness S. nodorum is from 10 to 20% crop loss, and in the critical years they may exceed 30-50%, and even more.

Septoria tritici Rob. et Desm. First described in 1842 Desmazieres on wheat, it is a major problem in areas with high humidity caused by frequent rainfall, such as the Mediterranean, Eastern, Central Africa, South America, Mexico, USA, New Zealand, Australia, Western Europe, Germany, UK, Russia, Ukraine, Belarus, the Baltic states, the countries of Central Asia, including Kazakhstan [4].

Mushroom especially harmful in the period from germination to the tube exit, but sometimes can cause extensive destruction and at the flowering stage. S. tritici develop mainly on leaves and leaf sheaths, rarely on the stems and spikes.

Losses S. tritici tend ogranichivayutsya edges and leaf veins are parallel and edge lines. Necrosis dotted with numerous black pycnidia with a glossy shade, easily distinguishable to the naked eye. On the ears symptoms are similar to S. nodorum, but, unlike the latter, pycnidia are formed more frequently in the upper half of the flakes. On the defeat of grain this kind of agent message indicates the presence of mycelium under his testa [5].

Pycnidia S. tritici spherical, 60-270 microns in diameter, piknospory colorless or greenish , thin , filamentous , straight yl slightly curved, sometimes tapered at one end, with 1-3 septa (rarely 4-7 ), size piknospor 29-85 × 1 5- 4 micrometers.

Microspores S. tritici mononuclear formed in pycnidia in okoloustichnyh cavities on the stems of wheat, their size 5-16 × 1-1,5 m.

Crop losses from S. tritici is 10-25 % and may reach 40-60 %.

Thus, septoria and its harmfulness for wheat occupies a great place not only in our country but around the world, to fight which is not so easy.

Literature:

1. Marland, AG Critical review of the genus in relation to the flora of Estonia / AG Marland. Tartu, 1948. - 230c.

2. JJ Kuzhantaeva Polymorphic species of Mycosphaerella johans and Leposphaeriia Ces. et de Not. / / Bulletin M -va Science, 1996, № 3, p. 53-60.

3. Koishibaev Murat. Disease of cereals. - Almaty: "Bastau", 2002, - 368 p.

4. DN Teterevnikova - Babayan, MV Bohyan / / Biol . journal . tissues of Japanese radish affected by Alternaria japonica / Phytopathology, 1967.

5. Peresypkin VF Kovalenko SN Symptoms of Septoria winter wheat under steppe of Ukraine . / / Micol. and phytopathogenic . , 1977, V. 11, no. 5, p.