Evaluation of safflower varieties for resistance to the fungal pathogen, Colletotrichum acutatum

The influence of plant growth stage, inoculum density, and variety on the disease severity and incidence were studied. Our results indicated that growth stage of the plant had no influence on infection rate, as the pathogen attacked 100% of tested plants. When applying three different inoculum concentrations to three weeks old safflower plants, no statistical differences were recorded, disease incidence ranged 32.0-47.0%. In this test, the 3rd and 4th evaluated leaves (the youngest) were infected more intensively than were the 1st and 2nd leaves. Among 11 safflower varieties tested for resistance to this pathogen, cultivar CW 1221 manifested the highest resistance with 8.3% infection, whereas two cultivars, Sabina and AC Sunset, were found to be the most susceptible with 90.0 and 83.3% infection.