More than 28ensp;000 oil-type and confectionary sunflower seeds (achenes) from several production areas in the United States were surface sterilized and plated onto agar media, and the fungi that grew from them were identified. Ninety-eight species in 38 genera were identified from graded samples (grade No. 1, grade No. 2, and sample grade) of seed stored at 20 deg;C at 63, 83, and 93 relative humidities and from developing seed field-grown in Georgia. Sixty-four fungal taxa are reported from sunflower seed for the first time. The internal mycoflora of sunflower seed grown in Georgia differed in 2 consecutive years; pre-harvest invasion of developing seed by storage fungi occurred during the dry growing season of 1983, and species diversity was greater than in 1984, which had a relatively wet growing season. Although fewer total genera and species were isolated in 1984, the percent of seed infected by and the number of species ofFusariumpresent in seed produced during the wet year were much greater than during the dry year. Forty-five potentially mycotoxigenic and five thermophilic taxa were recorded. Five species ofMicroascuspreviously unknown from sunflower seed were isolated.
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