The Resistance of Sunflower to the Attack of Some Pathogenic Agents in the Climate Conditions of the Northeast Baragan

Due to its national economic importance, the sunflower crop has established itself as the main oleaginous crop cultivated in Romania. It faces several diseases that are difficult to fight chemically. The creation of hybrids resistant to the attack of pathogens has proven to be an effective, safe, and environmentally friendly solution. This paper aims to examine the resistance of some biological sunflower creations created in Romania, to the attack of Phomopsis helianthi and Phoma macdonaldi fungi, in 2021. The experiment was placed in field conditions with a natural infestation, at A.R.D.S. Braila. The used biological material was represented by nine new sunflower hybrids. Two problem pathogens were studied: Phomopsis helianthi (perfect stage Diaporthe helianthi) and Phoma macdonaldi (perfect stage Leptosphaeria lindquistii). The climatic conditions of 2021 were favorable for the growth of the pathogens. Phoma macdonaldi had an average attack frequency of 38.8% and an average attack intensity of 1.71%, while Phomopsis helianthi recorded average values of 67.8% and 3.08%, respectively. The lowest attack degree of the Phoma macdonaldi pathogen was found in H3 (0.35%). Regarding the pathogen Phomopsis helianthi, the hybrid H3 showed good resistance, with an attack degree of 1.64%.