Short communication: Laboratory evaluation of nine highbush blueberry cultivars susceptibility to Drosophila suzukii (Matsumura, 1931) in the Southwestern Spain

Abstract

Aim of study:  To determine how susceptible the most used Southern highbush blueberry (SHB) cultivars were to the spotted wing Drosophila (SWD), Drosophila suzukii (Matsumura, 1931) (Diptera: Drosophilidae) as well as those recently introduced to Southwestern Spain.Area of study: Southwestern Spain (Huelva province).Material and methods: Nine of the SHB cultivars which were recently introduced in Southwestern Spain and the most used ones were selected: ‘Arana’, ‘Camellia’, ‘Kirra’, ‘Mayra’, ‘Misty’, ‘O'Neal’, ‘Sharpblue’, ‘Star’ and ‘Ventura’. In order to determine how susceptible the cultivars were to SWD, no-choice tests were performed under laboratory conditions. In addition, berry size, berry firmness, ºBrix, and pH were recorded in order to assess what influence these variables had on oviposition preference by SWD.Main results: Mean clutch size and mean number of emerged adults in ‘Star’ were significantly higher than in the other tested cultivars. ‘Mayra’, ‘Camellia’ and ‘Ventura’ received the lower clutch sizes and mean number of emerged adults. Mean developmental time (egg to adult) differed significantly among tested cultivars and were highest in ‘Camellia’ than in the other tested cultivars.  Only firmness and pH were correlated with SWD infestation as SWD females tend to oviposit more eggs in softer fruits than in firmer fruits. Results also showed that a higher pH increased the emergence of adults and shortened the egg to adult developmental time.Research highlights: Our results showed significant differences in the susceptibility of SHB to SWD. This information may help design IPM programs and in making recommendations for blueberry crops as planting of low-chill cultivars expands.