Characterization and manipulation of fruit susceptibility to Drosophila suzukii

Abstract

Drosophila suzukii (Matsumura) is an economic pest of small fruits and cherries that attacks intact ripening fruits. Host susceptibility may be influenced by characteristics such as flesh firmness, penetration force of the skin, total soluble solids (TSS, also known as°Brix), and pH. Improved knowledge of factors affecting fruit susceptibility is needed for developing thresholds and risk prediction models for IPM. A combination of laboratory and field studies was conducted to develop prediction and potential management tools. First, a direct bioassay was used to calculate the probability of oviposition in a given fruit based on various characteristics as determined across laboratory and field trials in Oregon and North Carolina, US. When multiple characteristics were evaluated simultaneously, oviposition probability consistently increased as penetration force decreased and pH increased. Oviposition probability sometimes increased as TSS increased. Second, raspberries and blueberries in unsprayed fields had substantially lower infestation in ripening fruit compared to ripe fruit. There was no or minimal infestation in green fruit. Third, given that skin penetration force influences oviposition, practices used to improve fruit quality were examined in laboratory no-choice cages for potential reduction of oviposition. Blueberry fruit sprayed with calcium silicate in the field had greater penetration force and firmness and reduced number of eggs laid by D. suzukii compared to untreated fruit. Other calcium-based treatments increased Ca content and firmness of fruit relative to untreated fruit. Timing of insecticide spray for D. suzukii might be delayed until fruit become susceptible.Keywords Brix Á Firmness Á Fruit preference Á pH Á Spotted wing drosophila Key message• Drosophila suzukii, spotted wing drosophila, is a serious pest of small fruits and cherries. • While fruits become more susceptible to D. suzukii as they ripen, the direct relationship between ripening characteristics and likelihood of oviposition was previously unknown. • The probability of oviposition on a given fruit consistently increased as skin penetration force decreased, and pH increased. • This knowledge is needed to develop thresholds and risk prediction models for IPM.

Potential host fruits for Drosophila suzukii: olfactory and oviposition preferences and suitability for development

“…Although D. suzukii has been reported to cause heavy damage to commercial blueberry and grape (Kanzawa, ; Kinjo et al, ), all other tested fruits were more preferred in choice assays, and this is consistent with the results of other studies (Lee et al, ; Bellamy et al, ; Lee et al, ). Blueberry and grape are the least fragrant of the tested fruits (Forney, ), which may explain their poor attractiveness when other fruits are present.…”

Variation of within‐crop microhabitat use by Drosophila suzukii (Diptera: Drosophilidae) in blackberry

“…It is unlikely differences in chemical parameters such as brix or pH impacted oviposition or subsequent development (Lee et al. ). Nor is it likely there was a significant difference in visual fruit traits (Poyet et al.…”

Strawberry Accessions with Reduced Drosophila suzukii Emergence From Fruits

“…Previous studies have investigated traits that contribute to the susceptibility of fruits to D. suzukii infestation, including fruit firmness or penetration force (Burrack et al, 2013; Kinjo et al, 2013; Ioriatti et al, 2015; Lee et al, 2015), pH of the fruits (Lee et al, 2015), and brix level of the fruits (Lee et al, 2011, 2015). However, little has been done to search for natural variation in susceptibility/resistance within genotypes of one fruit crop, which would allow identification of resistant genotypes and genetic determinants of fruit traits that can later be exploited for cultivar development.…”