SWD is a small, vinegar fly from Asia that has become a major fruit pest around the world. It first appeared in the United States in 2008.
Many of the habits and practices that have served fruit growers well for years do not work against SWD. […] If you think of SWD as a disease with “spores” that attacks your fruit from ripening through harvest, you will grasp the situation.
Unless you are trapping for SWD on your farm and have not caught any flies, you have to assume you have them. […] If you have ripe fruit, you need to protect it.
[…] if you caught SWD, they are laying eggs in your fruit. You should spray right now. This is not a pest where the capture of the first adult means the egglaying will begin several days later.
SWD likes the shade, so it is inside the bush or the tree, or over in the cool, dark woods. SWD is active during the cooler parts of the day in the early morning and late afternoon. In order to get good control, you need to cover the bush or tree. Penetrate sprays deep in the canopy and cover the backsides of the fruit. […] SWD does not spend a lot of time crawling around and systemic materials in the plant do not work against this pest.
you’ll need to reapply insecticides every week because there is not enough residue there to kill the SWD. […] I have been telling blueberry growers for five years they need to spray once a week. Many tell me at first they did not believe me, but now they say seven days is too long, it needs to be every five or six days.
Since there are several effective classes of insecticides, MSU recommends that no class of insecticide be used twice in a row and that growers rotate between chemical classes on every spray.
EDIT: A more updated article from OSU can be found here:
Very useful article! I picked up some useful info on SWD at last weeks North American Bramble Growers Conference. Here are some highlights:
Estimated damage from SWD in US is around 1 billion per year
Natural predator for SWD is still in quarantine with no expected release date.
Research trials showed no efficacy for sugar or yeast or both combined against SWD
Reasearch trials showed little or no improvement when combining adjuvants with insecticide
Research trials showed little of no improvement when adding sugar or yeast to insecticide
SWD in some area of California are developing resistance to Spinosad
SWD prefer a heavy leaf canopy in the center of the plant but reducing the canopy did no reduce SWD
SWD prefer Raspberries, Blackberries, Blueberries and Cherries in that order
Suggested spray time is early evening in order to protect pollinators and beneficials as much as possible
SWD prefer ripe fruit, but they are sometimes present in fruit as soon as it turns color
Thanks, I saw a fact sheet (one of the links in the article) that mentions many of those highlights. The point about resistance development is very worrying. What do you currently use to deal with it?
My day-neutral strawberries got hit hard last year and now that I am planting raspberries, blueberries and blackberries I expect to have to combat it in the coming growing season. I also have a 25’ ornamental cherry tree in my backyard that I suspect contributes to the SWD population.
Anybody know what time of year SWD becomes a problem? The article mentions starting spraying two weeks before fruit shows color but since I grow strawberries that ripen in June… I’ll pretty much be spraying all year.
There are some insecticides available to the commercial growers,like Mustang Maxx,that I’ve read about,that are supposed to be quite effective,but probably aren’t available for retail.
In the Seattle area,they usually are flying around,when the Himalayan Blackberries are ripening,sometime in August.
I haven’t tried to fight them yet.Most of the brambles I grow are early harvested and don’t need to be concerned about.bb
I’ve been lucky that swd hasn’t gotten this far north yet. i haven’t seen it in my everbearing raspberries so far. hopefully our extremely cold winters keep it at bay .
Moose you SHOULD consider yourself lucky because I know the folks over at the Honeyberryusa u pick had problems with them this past year and they get plenty of cold weather during winter.
Mustang is now available for homeowner use, as Sevin. Bayer sold the trade name Sevin to some outfit called Garden Tech. Garden Tech is now selling the active ingredient in Mustang (Zeta Cypermethrin) repackaged under the trade name Sevin.
My understanding is the Sevin dust form is still the old carbaryl, but the liquid is the same active ingredient as Mustang. Mustang is very effective against SWD. As mentioned, any insecticide used to combat SWD needs to be applied frequently because of SWD’s very short reproductive cycle.
For my purposes of growing strawberries, raspberry, blackberry and blueberries I am planning on going with alternating sprays of Spinosad (1 or 3 day PHI) and maybe Bifenthrin (1 or 3 day PHI).
sadly i think its just a matter of time before it shows up here. if and when it does ill have to kill my primocane varieties and plant summer bearing types. many of my other fruits ripen early enough to avoid them.
Since it seems to show up in mid-late summer, I don’t know why they are listing strawberries as a SWD candidate. All my strawbs are June bearers, and are done by mid-June. So, I suppose they are talking about everbearing and/or day-neutral varieties?
Yes many are popular like Albion, used in many commercial operations. For me it’s Mara des Bois. I have managed to control them where I’m not getting tremendous amount of damage.
I have been considering getting an everbearer like MdB, but sure don’t want to have to worry about spraying them a lot. I wonder since I haven’t harvested a lot of cane or other berries, that maybe SWD won’t be an issue at first? I know over time that may change as more plants come into bearing. But, we do have a few wild blackcaps and more wild blackberries, so maybe they’re already getting in those? They are all usually done by mid-July, so maybe not.
Nothing, I have too much other fruit they would rather have and I don’t have a ton of everbearing types, mostly June like you. They seem to leave them alone for now. I sometimes will dust everything with diatomaceous earth. One of my defenses against them. I use sevin and malathion on my stone fruit, helps with PC too, and I also use others like various peritherins like L-Lambda. I usually do not use these on berries, but when I leave for a few days every weekend like I do I use Malathion on them if nothing in bloom just fruits.
I removed most fruit the ripens during SWD season. That has worked best
