ALTERNARIA ALTERNATA (FRIES.) KEISSLE (SIN. A.TENUIS NESS., SIN. A. LONGIPENS (ELL. AND EV.) MEISON), POTATOES PARASITE IN YUGOSLAVIA

Alternaria alternata causes black spots on the leaves and berries of plants of the family Solanaceae, and is recorded as a corncab parasite (Panic and Maric, 1964) and a tobacco parasite (Ivanovic and Jovanovic, 1994). It appears in most cases as a weakness parasite on plants whose resistance dropped due to a shortage of nourishing elements, a drought year, virus infection, etc.
The symptoms are the same as the ones that cause A. solani, in this case the presence of A. alternata is followed by thick black spots, a carduroyer layer from conidia and conidiofora fungus.
In Dragacevo where the gro-production of seed potatoes is produced in Yugoslavia, the importance of the appearance of this parasite was registered in 1993.

The pathogen isolation was carried out cutting off part of the leaf with spots; sterilization was effected using absolute alcohol and sublimate 0.01%. On PDA make grey, lifted colonies with expressed concentric circles, with the appearance of crystal under the back of the colony.
It is characteristic that, by forming conidia in a row separated by 3 – 5 diagonal and 1–2 horizontal lines, the dimensions of the conidia are 6.8–18.04 x 16.07–46.25mm.
The fastest growth of mycelia fungus occurs on PDA. The optimal temperature for the growth of A. alternata fluctuates between 25° and 30°C. The optimal pH value for fungus growth is between 6 and 8 which depends on the isolate.
The night and day change have a great influence on the intensive growth of the colony and the sporulation of the parasites.

I Balkan Symposium On Vegetables and Potatoes

V. Cakarevic V, T. Boškovic

Alternaria alternata, colonia growth, conidia, isolate

https://doi.org/10.17660/ActaHortic.1997.462.153