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/

 

Agricultural Supervisory Leadership Certificate Program

June 17, 2022
June 23, 2022
June 30, 2022
July 7, 2022
July 14, 2022
July 21, 2022
July 28, 2022

Supervisors are critical to the success of farm businesses. They have a major impact both on employees' daily work experiences and on the production performance of the business. The  agricultural Supervisory Leadership certificate helps farm supervisors and managers learn and apply human resource management practices and leadership skills that foster rewarding workplaces and drive business results. Confident managers who thoughtfully apply leadership and management skills improve employee performance, develop teams, reduce employee turnover, and increase employee engagement. The courses within the certificate program will offer extensive practice and engagement activities to build confidence and skill sets.

Peru Weed Management and Soil Health Field Day

July 20, 2022
Peru, NY

Join us in Peru on July 20th as we discuss orchard weed and soil management! Speakers will be joining us from across Cornell's research and extension teams.  Topics will include the results of our herbicide timing trials, new vision-guided technologies for orchard weed spraying, organic weed management options, soil health demonstrations, and a discussion on our statewide orchard soil health survey. DEC credits are pending for this event.  

July Next Gen Meetup at Bowman Orchards

July 21, 2022
Rexford, NY

The July Next-Gen meet-up is focused on marketing. We will provide everyone who registers with a resource guide to farm stand marketing. The Bowman's have a farm store, U-Pick berries, sunflowers, apples and pumpkins as well as a commercial apple orchard. We encourage you to check out their website (Bowman Orchards).

Young farmers are welcome to attend, the focus of the program is farmers who are in the process of taking over a farm from the prior generation (whether family or not). Please pre-register by July 18  so that we know you are coming and can have enough food for dinner and resource materials.