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

Abstract

Drosophila suzukii Matsumara (Diptera: Drosophilidae) is an invasive vinegar fly that infests ripe and ripening soft skinned fruits. In the south‐eastern United States, blackberry (Rubus spp.) crops are heavily impacted by D. suzukii, and current management tactics rely on the use of broad‐spectrum insecticides targeted to adult populations. An improved understanding of D. suzukii biology and ecology are necessary to create sustainable management options. Knowledge of how D. suzukii interacts with resources will enable targeted management actions in the future. In this present study, we monitored larval infestation throughout the blackberry canopy and found that infestation was highest in the inner portion of the canopy and lower in more exposed locations. We also documented higher humidity within the cane canopy relative to the edge of the field. A difference in abiotic conditions may create within‐crop microhabitats that D. suzukii is able to exploit. Future research will explore how to take advantage of these microhabitats in pest management programs.

Evaluating a push–pull strategy for management of Drosophila suzukii Matsumura in red raspberry

“…). Greater infestation in the other lower hanging clusters was expected as D. suzukii prefer to oviposit in lower hanging fruit in the plant canopy, perhaps due to higher humidity or more shading . The extended protection to low hanging fruit in push plots implies that the deterrent odor negatively influenced D. suzukii oviposition throughout the 4 × 4 m plot, and perhaps acted to repel adults from these plots entirely.…”

Canopy spray deposition and related mortality impacts of commonly used insecticides on Drosophila suzukii Matsumura (Diptera: Drosophilidae) populations in blueberry

“…It is important to note that the MM values consisted of middle zone (MZ 43 ) and outer zone (OZ 57 ) fractions. The respective mortality fractions were based on the previously reported D. suzukii spatial occurrence within each canopy zone . Therefore, MM = (MZ 43 + OZ 57 ) values contributed 43% and 57% to the overall D. suzukii mortality.…”

“…In addition, the inner and middle canopy could be an optimal environment for D. suzukii egg laying due to shading, which results in lower temperatures coupled with higher humidity . The inner parts of the canopy are crucial within the blueberry bush in the context of D. suzukii biology and management due to a more favorable microclimate and higher population levels of D. suzukii . D. suzukii population levels and crop damage can be relatively high within inner and lower canopy, highlighting the importance of obtaining uniform spray deposition …”

“…17 The inner parts of the canopy are crucial within the blueberry bush in the context of D. suzukii biology and management due to a more favorable microclimate and higher population levels of D. suzukii. 18,19 D. suzukii population levels and crop damage can be relatively high within inner and lower canopy, highlighting the importance of obtaining uniform spray deposition. 18 Spray techniques undoubtedly impact insecticide efficacy for insects such as D. suzukii.…”

Mulching as a cultural control strategy for Drosophila suzukii in blueberry

“…Additionally, optimal female fecundity occurs at around 22 °C, and larval developmental time is shortest between 22 °C and 28 °C, whereas temperatures above 30 °C reduce reproduction and larval development . Adult D. suzukii tend to be more abundant and exhibit higher oviposition in the center of the plant canopy where RH is higher and temperatures are more moderate . Furthermore, D. suzukii pupae have higher survival rates in humid environments .…”