Isolation and detection of the fungi Alternaria dauci (Kühn) Groves et Skolk and Alternaria radicina Meier, Drechsler et Eddy from carrot seeds

Abstract

Carrot is among the most important vegetable crops because of its composition and vitamin content. The fungi belonging to genus Alternaria, especially A. dauci (Kühn) Groves et Skolk, causal agent of leaf spot and blight of carrots, and A. radicina Meier, Drechsler et Eddy, the agent of black root rot, can jeopardize the entire production of carrots. Both types can be found in a high percentage of seeds, carrots, parsley and celery. The method of detection filter paper (blotter method) and the method of isolation on malt agar were recommended by ISTA Rules. The presence of A. dauci (causal agent of leaf spot and blight of carrots) and A. radicina was performed on 12 samples of potentially infected carrot seeds originating from France, as part of laboratory ring tests. The presence of A. dauci and A. radicina using the filter paper method in 12 tested samples ranged from 0% to 21% and from 1% to 30% respectively. On MA medium the respective percentages ranged from 0% to 23% and from 1% to 31%.

Mrkva spada u veoma značajnu povrtarsku biljnu vrstu zbog svog sastava i sadržaja vitamina. Gljive koje pripadaju rodu Alternaria, naročito A. dauci (Kühn) Groves et Skolk, prouzrokovač lisne pegavosti i sušenja lista, i A. radicina Meier, Drechsler et Eddy, prouzrokovač crne truleži korena mrkve mogu da ugroze celokupnu proizvodnju mrkve. Obe vrste se mogu u visokom procentu naći na semenu, ne samo mrkve, već i peršuna i celera. U cilju njihove detekcije preporučuje se metod filter papira i metod izolacije na hranljivoj podlozi (ISTA Rules). Ispitivanje prisustva A. dauci i A. radicina vršeno je na 12 uzoraka potencijalno zaraženog semena mrkve poreklom iz Francuske kao dela laboratorijskih kružnih testova. Procenat prisustva A. dauci metodom na filter papiru kretao se od 0% do 21%, dok je A. radicina bila prisutna od 1% do 30%. Na hranljivoj podlozi procenat prisustva A. dauci se kretao od 0% do 23% a A. radicina od 1% do 31%.