Effects of Fruit Cooling on Spotted Wing Drosophila
In some of the first literature written in Japan in 1939 (Kanzawa, T.) about spotted wing drosophila, Drosophila suzukii, (SWD), experiments were made regarding the sensitivity of the egg and larval stages of spotted wing drosophila to periods of temperatures above and below freezing (32o F).
As is noted in the two graphs below, at constant temperatures of up to 35o F, 96 hours or more of cooling resulted in total mortality of spotted wing drosophila eggs and larvae. This was also anecdotally confirmed in tests conducted in 2009 in California.
While temperatures below freezing are not useful to fruit shippers, temperatures in the area of 35o F are useful. However, it is important to note that for success the constancy of the temperature is critical. So, while in an ideal situation constant temperatures of 35o F or a little below are effective in SWD egg and larvae suppression when extended for periods longer than 96 hours, the reality can vary significantly from the ideal. Shipped fruit ordinarily do not experience lengthy regimes of constant temperature as they are moved from place to place. Temperatures of a refrigerator truck can vary by location inside and placement of the produce (ie on the side, towards the bottom etc.), and certainly the temperatures at the point of sale can vary from the ideal to room temperature to even warmer.
Additionally, while initial damage from SWD on raspberries, blackberries and strawberries can be difficult to detect, this is not the case for other fruits such as cherries or blueberries, where the activity of SWD will leave an unsightly blemish.
The take home message from this information is that while extended cooling can be suppressive of SWD, growers should not rely on cooling alone. It will still be important to manage SWD in field.
Thanks to Shinji Kawai for making the information from the 1939 Kanzawa paper available.
This article was posted on the UC Santa Cruz county blog by Mark Bold on March 23, 2010. You can view more blog posts by going to: http://cesantacruz.ucdavis.edu/Strawberry_Nursery_Plant_Production/
Upcoming Events
Wine Sensory Evaluation Workshop
April 26, 2024 : Wine Sensory Evaluation Workshop
Staatsburg, NY
In collaboration with Jeremy Schuster, Viticulture Specialist at the ENYCHP, Dr. Anna Katharine Mansfield and Chris Gerling, Enology Extension Specialists with the Cornell Craft Beverage Institute, will be presenting a wine production-focused, interactive workshop on sensory evaluation.
What is my vine trying to tell me?
May 15, 2024 : What is my vine trying to tell me?
Plattsburgh, NY
Are your grapevines showing signs of discoloration or stunted growth? Don't ignore these warning signs! Join us on May 15th at the Cliton County CCE office to learn about the essential nutrients that grapevines require to thrive, identify the symptoms of nutrient deficiencies, and how to fix them. Don't miss out on this opportunity to improve your grapevine cultivation skills! Attendance is free, but registration is required.
How man's best friend can help find Spotted Lanternfly
May 21, 2024
Millbrook, NY
Come and join us at the Dutchess County CCE office on May 21st for a special demonstration by Jennifer Fimbel, the Agriculture and Horticulture Program Leader with Dutchess County CCE. You will get to see her SLF K9 Cole in action as they demonstrate how man's best friend can be used to detect the Spotted Lanternfly. Attendance is free, but registration is required