Spotted-wing Drosophila Host Preference and Quality Vary among Half-high Blueberry Cultivars

Spotted-wing drosophila (Drosophila suzukii; SWD) is an invasive pest in the United States that is responsible for significant economic damage to soft-skinned fruit and berries worldwide. SWD uses a wide variety of cultivated and wild fruit for reproduction. Host suitability may depend on physical and chemical factors of the fruit, with a positive correlation of SWD oviposition and larval development generally associated with soluble sugar content, softer fruit, and higher pH, and a negative correlation of oviposition with fruit firmness. Variety selection is an important tool for integrated pest management, but few studies have reported host suitability across varieties within a single cultivated crop species for SWD. In this study, we investigated SWD oviposition and larval development in five half-high blueberry cultivars, Chippewa, Northblue, Northland, Patriot, and Polaris, using no-choice and two-choice laboratory bioassays. Using a host potential index, our results showed that Chippewa was the most preferred cultivar for oviposition as measured in the number of eggs laid per fruit, and Polaris was the least preferred. The inverse was true for larval development, with a higher survival rate and adult emergence in ‘Polaris’ than in ‘Chippewa’. There was a negative relationship between fruit firmness and oviposition and a positive correlation between pH and larval development. The results of this study indicate that cultivar selection for half-high blueberries may be a promising integrated pest management (IPM) tool, although further research under field conditions is needed for validation.