hrvatski

Morfološke i kulturalne karakteristike Phythophtora megasperma (Drescler) var. megasperma, novog parazita uljane repice u Jugoslaviji.

On the field of OOUR Ratarstvo Lipovljani in the year 1980 it was noticed that a large number of the plants oil rape (variety Jet neuf) withered. The disease is characterized by a reddish discolaration of the older leaves followed by a sudden wilting of all the older leaves, which fall prostrate to the ground leaving the head or curd exposed. The lower end of the taproot, aften along with the unterground part of the stem was rotted and infected plants may be pulled from the soil with little effect. The cortex of the taproott and lateral roots was, saftened and watersoaked usually sloughs off, and remained in the soil when the plant is pulled out. About the upper edge of the diseased part of the root sometimes may be callus formation and adventitious roots sometimes produced. The fungus was isolated by planting tissue fragments taken from the margin of the lesion in selective ABK-malc agar (Cvjetković, 1982). The sporangia were without clearly seen papillae dimensions were 33.5-59.9 µm x 23.0-33.0 µm. Sexual organs appeared in abundance on the root of the host as also on the artifical supstrate. The diameter of the larger oogonia amounted to around 40 µm. Anteridia were in most cases paragyny. On V-8 supstrat 15% amphigynous and 85% paragynous anteridia were formed. Our isolated by its morphological caracteristics comformed to the original description of the Phytophthora megasperma Drechs. var. megasperma. (Drechsler, 1931). Acknowledgment

riječi uljana repica, Phytophthora megasperma (Drechsler) var. megasperma

We are most grateful to Miss Jane Stamps Ph D Commonwelth Mycological Institute Kew - London who confirmed our determination of P. megasperma var. megasperma. CAB Accession Number: 19841300945