Southeast Michigan fruit regional report – September 17, 2012
Apple growers are welcomed to attend an apple harvester machine demonstration on Tuesday, Sept. 18. Fall red raspberry growers should continue to trap for spotted wing Drosophila or check for infested fruit.
For apple growers, I want to make you aware of an apple harvester machine demonstration that is being held at Applewood Orchards in Deerfield, Mich., this coming Tuesday (September 18) at 9 a.m. This cutting edge piece of equipment has the potential to bring about landmark change in apple harvest technology. I look forward to seeing many of our east Michigan apple growers at Applewood on Tuesday morning for this demonstration.
Secondly, for fall red raspberry growers, I am continuing to get calls and emails from distressed growers who are discovering larvae or worms in raspberries. These worms are spotted wing Drosophila (SWD). In some cases, growers have discovered the fruit infestations themselves and in many other cases, growers are getting calls from customers with wormy fruit.
This “SWD Tsunami” of infested fruit is a difficult situation for raspberry growers to work their way through. I strongly encourage raspberry growers to continue to monitor traps closely for SWD catch and to do a simple fruit sample test to check for wormy fruit. I have had a good number of growers that have had only a few adults caught in traps, but when they checked for infested fruit, have found a good number of fruit infested with larvae.
If you have not been trapping for SWD or checking for infested fruit, I am encouraging you to do so immediately.
As I posted in my last fruit crop update, here is some information on a simple technique for sampling for larvae in fruit using a fruit dunk flotation method: Collect a standard sample of fruit (may be fruit for marketing, suspicious fruit or over ripe fruit missed by earlier pickings). Place the fruit in a plastic zip-lock bag and crush lightly to break the skin. Make a salt solution by dissolving 1 Tbsp. of salt in 1 cup of water and add this solution to the bag to cover the berries. After 30 minutes, examine the liquid to see if larvae are visible in the liquid. Larger SWD larvae will be visible as small, white pieces floating through the colored liquid. Placing this mix on a dark-colored tray is also an effective method for checking the sample for SWD contamination. Detection of small larvae may require the use of a hand lens.
Information on controlling SWD can be found in the recently updated publication Spotted Wing Drosophila Management Recommendations for Michigan Raspberry and Blackberry Growers. The MSU IPM Spotted Wing Drosophila website also contains a great deal of other information on trapping and controlling SWD.