There is an article in the June Fruit Growers News concerning a new approach that is being tested and looks promising thus far. Involves the application of a commercial, all natural sweetner called “Erythritol”. In a small trial it killed 75% of the larval in fruit. Higher doses of Erythritol shortened the life span of the adults and at even higher concentrations killed them out right. Which might be practical for bait stations as the SWD were actually more attracted to it than the fruit.
I see you can actually purchase Erythirtol from a number of places relatively inexpensive as it is used in cooking. Might be worth giving it a shot.
I have Erythritol to use as a sugar substitute for baked products. I also have Xylitol and Sorbitol for similar purposes. I have been wondering if they might be effective on fungal and bacterial diseases.
Edit: -itol indicates a sugar alcohol which are often sweet but have lower absorbability then sugar. Xylitol has only 40% of the calories or sugar and Erythritol just 5%. SWD simply consume and starve to death. They are also not Artificial, xylitol is analogous to wood pulp sugar and where wood aged sprits derive sweetness from. Erythritol is produced during fermentation. The mountain ash and Rowan Genus Sorbus named Sorbic acid and Sorbitol, Also found in high concentrations in European prune plums.
Malathion, Mustang Max and Delegate all have a short PHI on cane fruit in my state. We normally wait 3X the PHI before we pick just be be safe. Malathion and Mustang are broad spectrum. Delegate targets mostly worms or SWD. Mustang Max is normally restricted use due to bee toxicity. Malathion is common and inexpensive but not all versions are labeled for use on cane fruit.
According to the article I dont believe it had anything to do with the low calories killing the SWD. Actually more so the alcohol content that you referred to. I believe they contribute the death of larvae and adults from dehydration by the alcohol.
In their trial at USDA they dissolved 1/2lb into a gallon of water and sprayed it on the berries 1 time / week. As they told me Erythritol is not labeled for use in that way so couldnt tell me that I could eat the berries! However, if you pick the berries and sprinkle it on them you could! You are applying food to food, just not in the intended way.
I am making a couple of traps and going to try and spray a portion of mine to see what kind of results I get.