In Vitro Studies Regarding the Control of Cryphonectria parasitica with Hydroalcoholic

Abstract

Cryphonectria parasitica  (Murr.) Bar [syn. Endothia parasitica (Murr. And.] (anamorf: Endothiella sp .) is the causal agent of chestnut bark disease or chestnut blight. This disease produced great damages throughout the world, it has nearly eliminated the American chestnut tree ( Castanea dentata (Marsh.) Borkh.) from its natural range and has heavily affected the European chestnut tree ( Castanea sativa (P.) Mill). Successful protection against Cryphonectria parasitica is a very difficult problem because the conventional control methods against the fungus are not applicable with a great success because of the extreme fungus pathogenity and on the other hand because of the characteristics of sites and host plants. In our experiments the isolates of C. parasitica were picked from the Baia Mare area and for the control with plant extracts the isolates were inoculated on PDA medium that contained the extract using the poison food technique. The different extracts in three different concentrations were tested in 80 mm diameter Petri plates incubated at 25ºC and assessed after three, six and nine days of incubation. The fungistatic effect of the extracts was established by examining the presence or the absence of the colony growth. The colonies were measured establishing the colony area that appeared on the treated plates using the ellipse area formula. The results were expressed as the inhibition percent of the tested plant extracts.