Alternaria head rot on sunflower in the ne region of Romania

Abstract

Alternaria sp. infections can produce a major disease on sunflower worldwide, with yield losses as high as 60-80%, especially in warm and humid areas of Europa, India, Australia, America and some parts of Africa. Species as Alternaria zinniae and Alternariaster helianthi are responsible for Alternaria leaf blight and stem spot, that is considered a middling frecvent foliar disease on sunflower in Romania culture conditions. During summer 2024 diseased sunflowers plants with numerous tan or light-brown, slightly sunken cankers and scattered over the bracts and the back of the receptacle were observed in the climatic conditions from Iasi county, located in the NE region of Romania. Observations from the field revealed an extremely high percentage of affected plants, over 60% of the sunflower plants showed attack symptoms on the heads and seeds. According to the carried out analyzes, both by Alternaria zinniae and Alternariaster helianthi, were morphologically identified and described. Considering the fact that the genus Alternaria is ubiquitous and abundant in the atmosphere, as well as in soil, seeds and crop residues, but also of the increasingly pronounced climate changes and the EU regulations on the reduction of pesticide use and crop rotation, a strong knowledge and constant observations on this type of phytopathogens become essential.