Population Dynamics of Spotted Wing Drosophila (Drosophila suzukii (Matsumura)) in Maine Wild Blueberry (Vaccinium angustifolium Aiton)

Abstract

A long-term investigation of D. suzukii dynamics in wild blueberry fields from 2012–2018 demonstrates relative abundance is either still increasing or exhibiting periodicity seven years after the initial invasion. Relative abundance is determined by physiological date of first detection and air temperatures the previous winter. Date of first detection of flies does not determine date of fruit infestation. The level of fruit infestation is determined by year, fly pressure, and insecticide application frequency. Frequency of insecticide application is determined by production system. Non-crop wild fruit and predation influences fly pressure; increased wild fruit abundance results in increased fly pressure. Increased predation rate reduces fly pressure, but only at high abundance of flies, or when high levels of wild fruit are present along field edges. Male sex ratio might be declining over the seven years. Action thresholds were developed from samples of 92 fields from 2012–2017 that related cumulative adult male trap capture to the following week likelihood of fruit infestation. A two-parameter gamma density function describing this probability was used to develop a risk-based gradient action threshold system. The action thresholds were validated from 2016–2018 in 35 fields and were shown to work well in two of three years (2016 and 2017).

Olfactory Preference of Drosophila suzukii Shifts between Fruit and Fermentation Cues over the Season: Effects of Physiological Status

“…Although this reason may be valid in warmer regions, it cannot be the only explanation, as the same phenomenon was clearly observed in temperate climates [5,32,33,34,35,36,37,38]. It also has been stated that trap counts do not represent the actual population density, since they are influenced heavily by weather (cold, heat, rain) and the surroundings of the trap (presence of fruits, hibernation habitats) [35,36,39,43,44]. Weather can influence both activity as well as survival (and thus population density) of the fly.…”

Temporal Dynamics of Host Use by Drosophila suzukii in California’s San Joaquin Valley: Implications for Area-Wide Pest Management

“…For this reason, the availability of alternative hosts could play an important role in sustaining fly populations and dictating their local movement patterns when favorable hosts are not available. Researchers have provided a better understanding of local D. suzukii population dynamics [36,37,38,39,40,41]. Still, there are gaps that limit our understanding of the relative importance of different hosts for D. suzukii within some geographical regions.…”

Phenology and spatial distribution of spotted-wing drosophila (Diptera: Drosophilidae) in lowbush blueberry (Ericaceae) in Saguenay-Lac-Saint-Jean, Québec, Canada

“…Lowbush blueberry (Vaccinium angustifolium Aiton; Ericaceae) is a very important crop in Saguenay-Lac-Saint-Jean. Lowbush blueberry regularly supports high-density D. suzukii populations in Maine, United States of America (Drummond et al 2019). Their long-term study indicates that D. suzukii abundance and first appearance in spring can be explained by winter temperature, population density (trap captures) in the past season, local abundance of suitable wild berry plants, and predation (Drummond et al 2019).…”