Determination of common and pathogenic fungal loads on ornamental sunflower (Helianthus annuus Sp. L.) seeds and management strategies

Sunflower (Helianthus annuus Sp. L.) is one of the main oilseed crops worldwide. Recently, it is getting more popular as an ornamental use, as well. The aims of this study were to find out putative potential fungal load of ornamental sunflower seed lots and whether they affects on vigour performance of the seeds. Efficacies of the management strategies on problematic seed lots were also evaluated. For this purpose seeds have been treated with 100 mg O3/Nm3 and 200 mg O3/Nm3 doses ozone for an hour. As an other treatment, the seeds have been treated with 100 mg O3/Nm3 for an hour and later kept in the application boxes for 24 hours. For the last treatment, seeds have been soaked in water in order to keep them moist and treated with 100 mg O3/Nm3 dose ozone for an hour. Fungicide treatment has been performed by fungicide containing Azoxystrobin 75g + Metalaxyl-M 37.5g + Fludioxonil 12.5g active ingredients. Also the seeds treated by ozone were bioprimed by Mycorrhiza, Trichoderma harzianum. The most efficient disinfection method against Alternaria spp. contaminated seeds was 100 mg O3/Nm3 ozone treatment by an hour on the water-soaked seeds. Seed treatment fungicide had the highest efficacy for controlling Fusarium spp. on contaminated seeds. Keywords: Ornamental sunflower, seed-borne fungi, ozone, seed fungicide, mycorrhiza