- Author: Mark Bolda
The following is a summary of further comparisons of baiting techniques for the spotted wing drosophila Drosophila suzukii. Previous posts have evaluated the use of various fruit purees and other mixes and these have determined that a mixture of one 2.5 oz packet of yeast + 4 teaspoons sugar + 12 ounces of water distributed in four or five Mason jars were very effective in monitoring and evaluating infestation levels of spotted wing drosophila.
Another test of baits was run last week. Traps (a 500 ml Nalgene bottle with 4 holes in the lid) containing one pellet torula yeast (see photo below) dissolved in 100 ml water, the yeast + water + sugar bait mixture mentioned above and finally a commercial “filth fly mix” called Yellow Muse (AgBio Corporation) allowed to cure for several weeks (the fermentation process of this material may be important) were placed November 3, evaluated November 6 and then again evaluated November 9.
The results are shown below (numbers in columns refer to average numbers of flies captured in each trap):
“Females” means that they are vinegar flies without spots on the wings and assumed to be spotted wing drosophila (SWD), while males were readily identifiable with spots on the wings.
|
Treatment |
11-06-09 SWD “females” |
11-06-09 SWD males |
11-06-09 SWD total |
11-09-09 SWD “females” |
11-09-09 SWD males |
11-09-09 SWD total |
|
Torula yeast |
2 a |
2.5 a |
4.5 a |
2.3 a |
0.5 b |
2.8 b |
|
Yeast + sugar + water |
2 a |
1 a |
3 a |
7.8 a |
24.8 a |
32.5 ab |
|
Filth fly mix |
4.5 a |
15.3 a |
19.8 a |
17.8 a |
30.3 a |
48 a |
Means followed by same letter do not significantly differ (P=.05, Student-Newman-Keuls)
From the chart above, it is apparent that the torula yeast is not very attractive to spotted wing drosophila, while yeast + sugar + water continues to be, along with well cured Yellow Muse filth fly mix, the most useful.
Never did try that specific combination, but bananas (fermented with beer) were uninspiring. Remember too that this mixture could be a chore to service and find flies in. Do you have any results with that? Well aged Yellow Muse or the yeast, sugar + water worked very well through the summer. Reading the translations of the original Japanese work done in 1936 and 1939 indicate good rates of capture with red wine or sake, depending on the season.
Any other ideas ?? HELP
The person to speak with would be Bob Vansteenwyk at UC Berkeley who has taken the lead on SWD management in cherries. My understanding is that sprays would be initiated at first fruit color or first detected fly, but it is best to check with him or your local farm advisor to make sure.
Does the torula + sugar + water mix use the same torula yeast tabs you pictured? Or is it a different kind of yeast?
Mark