I was doing some research for Varroa mite control in bee keeping and came across some research from the USDA regarding pest control using methyl benzoate. Seems effective for many things, but I was particularly intrigued by it’s potential for repelling and killing what is likely our biggest enemy, SWD. Here is the article from the USDA, unfortunately it’s light on details: USDA ARS Online Magazine The Fragrance of a New Pesticide
Doing some Googling, I came across the patent application for use of methyl benzoate as a pesticide: US9629362B1 - Methods for killing insects using methyl benzoate - Google Patents There’s a lot of info in this application, but the main thing I’m taking away is that it seems very effective at killing SWD at concentrations of 1-2%. They tested it by soaking blueberries in solution then introducing adults, which died. I’m going to assume it would work as a spray of similar strength (the application mentions the potential of up to 10% strength, but 1-4% being better and 1-2% being best). Read this paragraph: “Oviposition deterrent activity: Of the VOCs tested (1% solution), MB surprisingly exhibited the most toxicity against D. suzukii. MB surprisingly caused complete mortality and no adult flies survived after 2 days exposure to pre-treated blueberries ( FIG. 2 ) (N=6, F=10.691; df=6,35, p<0.0001). All monoterpene VOCs tested did not show significant toxicity compared with blank control. Following subsequent further incubation at room temperature for 10 days, surprisingly no adults emerged and significantly fewer pupae developed from MB treated berries compared with blank control and all other essential oil treatments ( FIG. 3 ; N=6, df=6,35; for adult, F=4.843, p<0.01; for pupae, F=3.586, p<0.01), indicating that MB also surprisingly possessed strong oviposition deterrent property.”
From further down in the application is about it’s safety to people: “Methyl benzoate is of low to moderate human toxicity by ingestion and inhalation (Clayton, G. D., and F. E. Clayton, Patty’s Industrial Hygiene and Toxicology: Volume 2A, 2B, 2C: Toxicology, 3 edition, New York: John Wiley Sons (1981-1982); Opdyke, D. L. J., Monographs on Fragrance Raw Materials: A Collection of Monographs Originally Appearing in Food and Cosmetics Toxicology, pp. 356, Oxford: Pergamon Press Ltd., 1979)). It is approved by the US Food and Drug Administration (21 CFR 172.515) and the European Union (EU Regulation 1334/2008 & 178/2002) for food use and is commercially available as food-grade flavor ingredients from many chemical companies.”
I found it for sale for perfumery purposes here: https://www.etsy.com/listing/4494824...MaAilCEALw_wcB
At 1% you would need 379 mL (about 2.5 tablespoons) per gallon, so it’s not super cheap from this source. I would stress that pure methyl benzoate in that volume isn’t super safe for you…gloves and goggles would be wise, perhaps a mask, too.
So to recap: it seems an application of 1-2% methyl benzoate, a chemical already in use for flavoring and perfumes, is a highly effective repellent and pesticide of SWD larva and adults. I’d surmise spray applications will be as effective as the soaks discussed in the patent application, but an emulsifier would be needed. Something like aloe vera gel or glycerin could work according to hasty search. This site also has a method that seems more legitimate: https://pharmlabs.unc.edu/labs/emulsions/agents.htm . As this method appears to kill both adults that try to oviposit as well as larvae, application intervals would need to be figured out by trapping/monitoring when adults are present (assuming they arrive from outside areas).
I may try this, but hopefully someone can make use of this information! I saw it mentioned in passing in a thread from last year, but didn’t see info in depth.
Hopefully it’s available on the market soon as a RTU product, seems like it could be a real beneficial product.