Raspberry/blackberry/Strawberry new fruit fly maggot problems
Late last season and throughout this season I discovered small 1/8' white maggots in a large number of my raspberries and blackberries. I only discovered them because I apply the following procedure after harvesting the berries. I am a biodynamic gardener and don't like to spray fungicides. To prevent the fruit from rotting or prevent mold for a few days I usually put the berries into a Food Saver Vacuum container and suck out the air. This brings the maggots to the surface but does not kill them. At least I am able to find them and discard the effected fruit. However, later in the season there were so many maggots that I did not bother to harvest the fruit.
I contacted an expert from Nourse Farm which I consider the best berry nursery in the U.S. and she felt that the maggots came from SPOTTED WING DROSOPHILA which was introduced to the U.S. from China recently, rapidly spreads and has become a huge problem for growers of raspberries, blackberries and strawberries (see link below).
I have tried to spray but found out that these flies quickly develop resistance to all commercial sprays. Still, early in the season one can limit the damage by first spraying with a product that contains Spinosad (considered a natural product and approved for use in organic agriculture by numerous national and international certifications). This should be followed by Malathion and lastly, a Pyrenthium based insecticide maybe in combination with Canola oil like Pyola. Anyhow, my fruit growing and jam making days are over and with this knowledge I am even less inclined to buy commercial black- rasp- or strawberries, which now need to be sprayed even more. Next year I will convert my Autumn Bliss/Heritage raised raspberry bed to a new crop and my other raised raspberry and blackberry beds will probably follow.
Very sad but it is a trend that I have observed since I started to garden as a child. Every year, especially recently, we get more and more diseases from newly introduced and pesticide resistant insects and fungal diseases in plants. Add to this the ever growing multiple strain resistant human diseases that now appear all over the world (1 million Chinese suffer from multiple strain resistant tuberculosis) and you know that humans will face a serious crisis.
One last piece of information for outdoors enthusiasts. The EPA recently issued a statement that since 1960 we have seen 400 new Zoonotic diseases (disease we acquire from animals). West Nile virus, hanta virus, SARS are just a few examples and gardeners will have to protect themselves from many new diseases, many of them transmitted by mosquitoes. Unfortunately, there are new day active mosquitoes like the Asian Tiger Mosquitoes here in the U.S. now that are very aggressive, replace the usual mosquitoe species and spread like wildfires. Paste this link into your browser.
Here is a link that might be useful: spotted-wing-drosophila