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ARS Home » Pacific West Area » Corvallis, Oregon » Horticultural Crops Research Unit » Research » Publications at this Location » Publication #317984
Title: Humidity implications for populations of Drosophila suzukii (Diptera: Drosophilidae) on blueberry

Author
item TOCHEN, SAMANTHA - Oregon State University
item WOLTZ, JESSICA - Oregon State University
item DALTON, DANIEL - Oregon State University
item Lee, Jana
item WIMAN, NIK - Oregon State University
item WALTON, VAUGHN - Oregon State University

Submitted to: Journal of Applied Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/20/2015
Publication Date: 7/2/2015
Citation: Tochen, S., Woltz, J.M., Dalton, D.T., Lee, J.C., Wiman, N., Walton, V.M. 2015. Humidity implications for populations of Drosophila suzukii (Diptera: Drosophilidae) on blueberry. Journal of Applied Entomology. doi: 10.1111/jen.12247.

Interpretive Summary: Spotted wing drosophila (SWD) is an invasive pest of soft-skinned fruit and can cause severe economic losses in a wide range of susceptible crops. A study was conducted on determining how relative humidity (RH)affected the survival, development and fecundity of SWD in a lab study. Also, we looked at the relationship between the humidity around traps and numbers of SWD captured in them. Five humidity levels were used in the lab: 20, 33, 71, 82, and 94% RH at 20.6 ± 0.2 ºC. As humidity increased, fecundity and longevity increased. At the higher humidity levels, there was limited impact on mean generation times (T), larval development and eclosion times. Females had a higher number of mature eggs at 82 and 94% RH, compared to 71% RH. In the field, low ambient humidity levels resulted in decreased trap captures of SWD than at higher humidity. This information can be used to refine predictive population models for SWD and supports the hypothesis that cultural practices that minimize lower humidity levels in crops can contribute to management of SWD. Such methods may include open pruning, drip irrigation and field floor management.

Technical Abstract: Temperature and humidity affect insect physiology, survival, fecundity, reproductive status and behavior. Drosophila suzukii is an invasive pest of soft-skinned fruit and can cause severe economic losses in a wide range of susceptible crops. This study was conducted on blueberries to determine the effect of humidity on D. suzukii larval development, adult survival, fecundity and reproductive status. In addition, we correlated long-term field trap captures to concurrently recorded relative humidity (RH) levels in close proximity to those traps. The five constant humidity levels in laboratory bioassays were 20, 33, 71, 82, and 94% RH at 20.6 ± 0.2 ºC. As RH increased, fecundity and longevity increased. At the higher humidity levels, RH had limited impact on mean generation times (T), larval development and eclosion times. The highest net reproductive rate (Ro= 68) and highest intrinsic rate of population increase (rm =0.17) were both recorded at 94% RH. The reproductive status of females, as indicated by the number of mature oocytes per female, was significantly greater at 82 and 94% RH, compared to 71% RH. In the field, low ambient humidity levels resulted in decreased activity and estimated population levels of D. suzukii, relative to populations at higher humidity. This information can be used to refine predictive population models for D. suzukii and supports the hypothesis that cultural practices that minimize lower humidity levels in crops can contribute to management of D. suzukii. Such methods may include open pruning, drip irrigation and field floor management.