(409) The Impact of Tarnished Plant Bug Damage on Antioxidant Characteristics of Organically and Conventionally Grown Strawberries

Abstract

Six strawberry cultivars (`Earliglow', `Honeoye', `Idea', `Jewel', `Northeaster', and `Seneca') were grown organically on three different composts (yard waste, dairy barn waste, and vermicompost). Organic treatments were contrasted against a synthetic fertilizer standard, a conventional pesticide standard and an untreated control. Plots were rated for tarnished plant bug (Lygus lineolaris) damage during the growing season. At harvest, berries were examined for their ascorbic acid levels and total anthocyanin and phenolic contents. Ascorbic acid content of berries in different cultivars and treatments were similar. As expected, fruit anthocyanin and phenolic contents were significantly different among the cultivars, and ranged between 160–230 μg·gfw-1 and 1039–1333 μg·gfw-1, respectively. Among treatments, anthocyanin contents of strawberries were not significantly different, but berries grown on the conventional pesticide standard had 8% to 12% lower total phenolic content than the other treatments. In organic treatments, production of phenolic compounds may have been induced in response to increased tarnished plant bug feeding. This putative biotic stress defense mechanism was seen most dramatically on tarnished plant bugsusceptible cultivars. However, as differences in phenolic levels were greater among cultivars than among treatments, cultivar choice may be a more important consideration than growing system for optimizing antioxidant levels in commercially available fruit.