Devastated by Drosophila suzukii

Axel(12b/Sunset H2)October 9, 2012

This is the third year in a row that I've had a complete crop devastation from Drosophila suzukii. The infestation is so bad that my apple crop is 80% destroyed.

Thanks to this pest, I will say my good byes to the majority of the soft fruit crops I have grown so far. I will be removing every last blackberry and raspberry vine off my property, remove most sour and wild cherries. I will be tearing out the majority of my plums, pluots and peaches, leaving just the bare minimum my family can consume. I kid you not, the infestation was so bad, it's not even worth having any of these fruits around, they just rot on the branches and vines.

Without the soft fruit, the pressure on apples and pears isn't that great. But with a ton of soft fruit around the last few seasons, the population simply exploded this year. Thanks to this fruit fly, my fruit hobby will focus from now on more on non-soft fruits. This fly has single handedly destroyed my dream of an orchard where you can just walk in and always find something ripe to eat. I have to focus now on harvest schedules and making sure crops get removed from the trees as soon as they begin to ripen.

I've discovered the number one vector for the fly is the raspberry, followed by blackberries and then capulin cherries. There is no point on trying to grow any of these fruits unless I am willing to create a permanent enclosure with mosquito netting.

I guess I'll just be buying my berries at Trader Joes. And if anyone would ask, I would never, ever recommend any home gardener to even bother with blackberries and raspberries, it's not worth the trouble. Drosophila suzukii has rendered it nearly impossible to grow these, even strong pesticides don't really work.

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How will you control it on the leftover peaches and plums?

    Bookmark   October 9, 2012 at 6:53AM
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alan haigh

Axel, I am so sorry. Seems like fruit is becoming as hard to grow on the west coast as in the east. Maybe some non-synthetic methods will be developed to handle this pest- I assume they searching for affective predators.

    Bookmark   October 9, 2012 at 7:03AM
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Scott F Smith(6B/7A MD)

Argh, I'm sorry to hear that Axel. That guy makes the BMSB sound downright friendly.

I have found a similar problem with the BMSB in my orchard, there is a season-long smorgasbord laid out for it - berries to stone fruits to pears and apples. Same goes for the wasps, I have built up a large population of these huge nasty wasps based on their surfing my different crop waves over the season. Similarly for birds as well. Its a dark side of growing lots of different fruits in a small area.


    Bookmark   October 9, 2012 at 8:54AM
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alan haigh

Scott, wasps were a huge issue at all orchards I managed this year regardless of range of fruit.

    Bookmark   October 9, 2012 at 9:13AM
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fruitnut Z7 4500ft SW TX


Wow, that does sound awful. Makes one wonder how the commercial growers are going to manage, especially berry growers in places like OR. They must be spraying every week. You'd have to keep them from building up. This is the pest I'd least want to see in my greenhouse. But I didn't even see any of the normal fruit flies this year.

Don't need any stink bugs or wasps either. I don't know how you guys out east manage all the pests. It doesn't sound like fun to me.

    Bookmark   October 9, 2012 at 9:57AM
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As 'Newbie' it is 'challenging' at best ( in the northeast). If I didn't spray or net I wouldn't have fruit at all. I would love a greenhouse!

    Bookmark   October 9, 2012 at 10:59AM
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Axel(12b/Sunset H2)

This past year I watched the cycle more closely. I had made a commitment to get on the problem early and keep population under control. With the cherries it worked. I netted the cherries, and what didn't get netted got eaten by the birds, so there was little chance of the population to take off on my cherries. Since they are the first soft fruit to ripen in my orchard, populations are still low to begin with.

But as soon as the raspberries started to ripen, the population took off. I did not put netting over my raspberries, it's too hard to seal, I'd have to bury the netting, because the flies enter from below. Then they infested the blackberries with a vengeance, there I did have netting but not sealed from below.

The apricots came in next but were left mostly alone. Only the fruit left to over-ripen on the tree got infected.

I have a large collection of plums, peaches, nectarines, and pluots. The pluots got completely infested, at which point the population was so large there wasn't much I could do without a ton of work. There was literally a cloud of bugs over the trees, with wasps kicking in to finish off anything rotting on the tree.

Apples and pears were left alone until all stone fruits and soft fruit disappeared, then apples and pears got them. The maggots don't survive in the apples and pears, they just damage them.

Based on what I observed, I have to either hermetically seal-net the berries or get rid of them. If I seal them I don't know if they will get pollinated. I haven't decided yet, but most likely will just remove the berries, they are easier to buy and taste just as good from the store.

But no matter what, I have to cull my stone fruit collection. I will probably dwindle my collection down to a very small list that I can easily manage. I am definitely chain-sawing my pluots, they are worthless in my climate, and the peach collection will be reduced down to four small trees of "snow beauty", "frost", saturn, and one more. Plums will get dwindled down to one Japanese multi-graft tree and one European multi-graft tree. My apricots produce so little I will just leave them as is.

Scott is right, growing a lot of fruit in a small area is bad news. I will be making more of an effort to "quarantine" all the stone fruits into one area of the garden. I may just put them all in a single row and put up a permanent frame that gets netting every year.

The bad news is that this means starting over and re-engineering my entire orchard.

    Bookmark   October 9, 2012 at 1:33PM
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"How will you control it on the leftover peaches and plums"

You need to hit the trees hard with malathion.

    Bookmark   October 9, 2012 at 5:19PM
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I'm a little north of you (Silicon Valley) and I'm worried about this pest. So far they haven't found us but I'm sure it's only a matter of time. Our most susceptible fruit is probably our mulberry. No cherries, raspberries, or blackberries here, but we do have an awful lot of other fruit growing. I worry about the grapes and blueberries, too, but the apples are my favorites.


    Bookmark   October 9, 2012 at 9:07PM
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UC Davis Pestnotes recommends Spinosad as a least-toxic spray, but says that timing is critical.


    Bookmark   October 9, 2012 at 10:19PM
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jean001a(Portland OR 7b)

Lots of info at Oregon State University

Here is a link that might be useful: re SWD

    Bookmark   October 9, 2012 at 11:38PM
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I'm wondering if bagging apples might be a useful strategy for those with only a few trees.

    Bookmark   October 10, 2012 at 3:23PM
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Axel(12b/Sunset H2)

I am pretty sure that removal of the blackberries and raspberries will make a big difference. The raspberries are by far the absolute worst vector.

I will continue to use GF-120 to keep the population from taking off, as long as I have little rotting fruit and no more raspberries and blackberries, it should be fine.

    Bookmark   October 10, 2012 at 3:38PM
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milehighgirl(CO USDA 5B/Sunset 2B)


"This fly has single handedly destroyed my dream of an orchard where you can just walk in and always find something ripe to eat."

I have the same dream and I can only imagine your heartbreak. I am terribly sorry.

    Bookmark   October 11, 2012 at 11:21PM
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The first reports from the University of RI(hort dept.) to all of us fruit growers this early spring, was about setting out traps to count SWD. The count became large very quickly, and really picked up in June/July. They never got to me in Newport, RI, but the rest of the state suffered. The strawberry crops were badly hurt as were blueberries. It is a nasty thing. So sorry, Axel. Mrs. G

    Bookmark   October 12, 2012 at 9:27AM
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alan haigh

The recent increase in pest pressure is truly alarming. I wonder how organic fruit production strategies will be able to keep up. I would have lost my peach crop to stinkbugs this season without the use of pyrethroids. Seems like SB's and DS are going to be either impossible or very difficult to deal with organically. Hard enough with all the benefits of modern chemistry.

When consumer goods were mostly manufactured in this country the introduction of new pests was probably much slower as a result.

    Bookmark   October 12, 2012 at 10:30AM
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Axel(12b/Sunset H2)

Looks like the Monterey Bay area was ground zero for drosophila suzukii in 2008. That seems to be about the time when I first discovered damage from the fly in my own orchard. I remember the capulin cherries were full of holes, I thought at the time that it was bird damage, but the holes were too small for birds.

For those curious, this is the first entomologist blog post for this pest ever posted in 2008:
Ground Zero Post

Looking at this post, it becomes clear that raspberries are a primary vector and this explains the proliferation of this pest in my orchard. In fact, the advice from this initial post is as follows:

"It is advisable not to leave strawberries and caneberries to continue to fruit without harvest over the winter, as it is suspected that the D. suzukii will continue to breed and multiply in these areas. "

Of course, in my orchard, we can't eat all the raspberries and blackberries, a number of them end up rotting on the canes, hence why I want to remove them.

Frank Zalom and Mark Bolda
Dept. of Entomology, Univ. of California, Davis, CA 95616
UCCE, Santa Cruz and Monterey Counties, 1432 Freedom Blvd. Watsonville, CA, 95076

An unusual outbreak of a Drosophila that was infesting marketable fruit was noticed in the Monterey Bay Area of California during Fall 2008 and resulted in phenomenal rates of fruit infestation in both strawberries and caneberries, well over 50% in some cases. This insect was later identified as the spotted wing drosophila, Drosophila suzukii. The fly has now been reported from virtually all coastal California counties and a number of central valley counties as well. Descriptions of damage to caneberries and strawberries, and results of monitoring and control studies in the Monterey Bay area that have been ongoing since Fall 2008 are presented.

    Bookmark   October 12, 2012 at 12:37PM
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Axel(12b/Sunset H2)

Apparently this pest is now in the entire US, I even found berry orchards in North Carolina that have complete crop losses this year and last year:

Qualla Berry Farm

Once again this year we are dealing with the same pest which destroyed most of our fall crop last year, the Spotted Wing Drosophila. The fruit flies have again created a major loss of our raspberry crop and we have been unable to offer U-Pick this fall 2012.

The more I read about this, the more it might be worthwhile to put in some extra effort to keep the berries as prices are going to go through the roof. I was thinking of setting up a scaffolding around my berries to keep the fly out. it would have to be hermetically sealed, but it would be worth it if it gets too expensive to buy raspberries.

    Bookmark   October 12, 2012 at 1:10PM
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Axel, sorry to hear how hard your struggle and loss is.

SWD showed up in southern VT in a minor way at the end of last summer. This summer it was present throughout the state by the end of summer. Again mostly in a minor way although I understand there were some heavy losses at some locations. At this point everyone is holding their breath waiting to see what the over wintering ability is. A slow wave of bugs moving north late in the season could be dealt with. But a local population building from spring...well that would be a much greater challenge.

    Bookmark   October 12, 2012 at 2:24PM
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Noogy(6 sw mi)

Last year was the demise of our super-raspberry patch. We still haven't recovered. I hear you can manage them with a vinegar trap, where they are atracted to the smell and get stuck.
Good luck.

    Bookmark   October 13, 2012 at 2:23PM
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fruitnut Z7 4500ft SW TX

Hey this scares me a little too. But I think the real problem comes in when they are left to breed to high numbers on rotting fruit. Berries are bad in that regard since there is always going to be unpicked and rotting fruit. If one harvests all the fruit on time and leaves nothing to rot, then I suspect the situation will be managable. Scaring everyone needlessly isn't productive.

    Bookmark   October 13, 2012 at 3:55PM
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franktank232(z5 WI)

More production will have to move under plastic/glass...

    Bookmark   October 13, 2012 at 4:13PM
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SWD flies initially attack ripening fruit, unlike most other fruit flies. I keep all over-ripe fruit and rotting fruit cleaned out of the small patch, hard to say if this reduces the fly population as ripening fruit outnumbers rotting fruit in my patch by hundreds to one.

I trapped well over 1,000 flies in both 2011 and 2012 using 4 small apple cider vinegar traps. I have no idea if this reduced the number of fruit attacks or simply attracted more flies to the berry patch.

When the infested berries are refrigerated or frozen, many of the larva emerge and can be picked out or brushed off the berries. Filtered berry juice will also be larva-free.

Salt water will also cause emergence, not sure if the salt water could then be completely rinsed off the berries.

In my case the flies do not deform the berries or turn them to mush like other attacked fruits. This whole fly thing is distasteful, but I have been able to use the bulk of my berries.

    Bookmark   October 13, 2012 at 11:23PM
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Noogy(6 sw mi)

Fruitnut, you're absolutely right. My patch is almost impenetrable and think wider rows less vigorous infestations will result cause I can see the berries I may have originally missed. This year our chickens and turkeys were directed into the patch after picking.

    Bookmark   October 14, 2012 at 7:18AM
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Okay I've never written here before tho I've been a member for long time. I grow 11 varieties of fruit. I've started finding maggots in my blackberries. My BB's are tame regular garden variety. We've picked 50+gallons of berries each season and I put them up in pie filling, jelly, jams and juice. When I started picking I washed em and noticed the berries. I washed em twice and still had them. THe only thing I feel safe in putting up is filtered juice that I can make jelly, cordial and juice from. We didn't have any worms in our raspberries which are in backyard with blackberries. Front yard we have apples, pears and cherries and had a good year. I don't want to spray nasty stuff on berries and don't want to eat worms so I think I should just pull them up. Should I burn the canes w/fruit on them-or pick the fruit and give it to my friend who has chickens? If we had chickens on our place would they help prevent this fly/worm problem? Will treating the soil get rid of the problem? I'm thinking of planting blueberries in place of BB in same site. Any issues with that?
Sorry so many questions but I'm just devastated and want to do the right thing. Thanks in advance for your advice. I do net my fruits to prevent birds from carrying off fruits but I don't think my 1/4" netting will keep out these worm flys. The blackberries were netted every year but this year because my husband has cancer and is in treatment and too weak so wasn't able to put the net up. When u say hermetically sealed what kind of net are you talking about? I have some white cloth net we used when cicadas came thru in 1998 that works well on cherry trees after they've been pollinated by the bees. OK I'll stop now. Too many ?'s. Thanks everyone.

    Bookmark   August 10, 2013 at 3:10PM
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fruitnut Z7 4500ft SW TX

I think any of the berries will get hit. So blueberries probably no better than blackberries. Trying to screen them out seems almost impossible to me. If you don't want to spray I'm not sure there is an answer.

    Bookmark   August 10, 2013 at 4:21PM
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Axel(12b/Sunset H2)

My answer has been to seriously cull my orchard. That means pulling fruit trees and vines to bring the size of the orchard down to a level that I can actually manage.

Ive given up on the dream of having a bountiful orchard with an over abundance of fruit, there is no point. It's too much work. We are bringing things down to a level that there is just enough to eat fresh.

    Bookmark   August 10, 2013 at 7:41PM
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jean001a(Portland OR 7b)

Lots of info for home gardeners here[]=443&tid_1[]=423

One thing they haven';t yet changed on the site, the traps no longer use the yellow sticky card. Found it didn't increase the catch.

Here is a link that might be useful: home gardener info re SWD management

    Bookmark   August 10, 2013 at 8:06PM
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I was emailing back and forth with Richard Cowles of the CT Agricultural Experiment Station, entomologist who is working on baits and controls. He gave me this recipe for bait:

"I was the one who came up with the vinegar, grape juice, alcohol combo. It is an alternative to 60:40 mix of red wine:apple cider vinegar. This mix is much, much better than apple cider vinegar alone. It is also only a fraction as attractive as the actively fermenting baits, the best of which, so far, is

12 fl oz water

1 c whole wheat flour

1 Tbsp apple cider vinegar

1 Tbsp active dried yeast

Yes, this is a super-attractive bait.

You could probably use less yeast, and simply let it multiply."

No sticky card needed, though it is easier to count the flies. I was seeing flies around a patch of wild blackberries that were shaded. The 90-degree temps in July probably kept them from moving in too early but they're here now. He suggested netting the TC blackberries I planted last year that are ripening now, but problem is primocane-fruiting raspberries are still flowering and bees need to get in.

He's working on some new methods of control, but it's a challenge:

I am working on a number of tools, including attract-and-kill baits, and am improving attractant traps to the point where it may be possible to protect cane fruit with the combination of Entrust and use of these traps. The problem is that Entrust may only be used twice, and then a different class of insecticides is legally required before you return to using Entrust. Plus, Entrust may only be used three times, totally, on one crop. Without an effective insecticide to use in a rotation with Entrust, organic production of cane fruit while maintaining fruit quality when SWD are present is practically impossible."

He said some flies seem to be recovering after spraying pyrethrins, but since you have to use a different class after using spinosad, I don't know what else an organic grower could use. I suggested kaolin clay and he replied that it was promising:

" I believe that SWD can travel several hundred feet in a day through fruit crops. They also disperse throughout a crop because they may travel back and forth to shady places in nearby woods.

I believe that kaolin clay is a good option. Based upon my lab tests, flies encountering the clay are repelled and die within a few hours (it’s a pretty good desiccant).

Pyrethrins have not proven to be effective. There are reports that the flies may recover following poisoning, which is a very bad development. "

Fine netting (I'm using sheer curtains) after pollination is the best we can do right now. I'm not selling any more soft fruit this year - just using the blueberries I picked in July and froze for jams. The domesticated RB and TC BB are too few to market, only planted a few last year but they're spreading, I was hoping to have a nice patch for market in a few years. Wild blackberries are fairly prolific (a little dry in July for them) after last year's drought and I was planning on a good cash crop with them this year but unless I pick the small patch just renovated 2 years ago (in full sun) and test with fruit dunk and don't find any larvae I won't be selling those. Of course the soak (and crush) makes them unusable for fresh, have to make jam or jelly out of those too.

I do have yeast traps out he suggested every 30ft in grid pattern, so far I've just put them where I've seen the flies b/c I don't want to attract them to other areas. But netting the wild ones is not an option. I'm going to email him again and ask if I should just clear-cut and bag the infested area I've found along the roadway, or if I should keep the canes and traps there (while picking any overipe or damaged fruit to prevent reproduction) as a "trap crop".

I didn't know they would infest apples and pears, thought it was just soft fruit. There is concern that Junebearing strawberries may be at risk - everbearing are.

    Bookmark   August 10, 2013 at 10:10PM
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jean001a(Portland OR 7b)

SWD will infest apples and pears if the skin is broken. Same goes for grapes.

    Bookmark   August 11, 2013 at 12:33AM
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Two things: for your own crop of berries, try the ice and salt bath. See if the infested berries drop to bottom; then you can take the ones on top. This worked for me last year on Heritage red raspberries.

Wondering if there is any research on imidacloprid as a soil drench? My understanding is that the flies pupate in the soil. Does anyone know of any research in this area?

    Bookmark   August 12, 2013 at 8:27AM
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Just saw these instructions on making an attract-and-kill trap. Not sure why the wine/cider 'Drown" solution is needed if the bait in the small cup (same recipe Dr. Cowles emailed me) is effective, you would think they would drown in that (and it's cheaper than even a cheap red wine). I need to go check my traps tomorrow, we'll see if the yeast makes it too foamy and they float. But I made it the week before without the flour and vinegar and it worked.

I've been using quart yogurt containers with lids, but the red-label frosting container was more attractive and a good size (16oz). The problem with drink cups is finding lids to fit.

And yes, next time I pick a good amount of berries I'll use the sugar solution fruit dunk, last quart and a half or so I picked had some larvae in them so I threw them all away

I don't know the ice and salt method - the good berries float, and aren't too salty/soft to use as fresh (even sell?)

Talked to another vendor who has 3000+ bushes yesterday - she's selling garlic now b/c the infestation is so bad her blueberries and bramble berries are unmarketable.

Edited to add the link!

Here is a link that might be useful: UCONN IPM SWD Trap

This post was edited by ajsmama on Mon, Aug 12, 13 at 22:34

    Bookmark   August 12, 2013 at 10:30PM
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When we first bought our house 18 years ago, I battled a Himalayan blackberry, thank you very much Luther Burbank! That led me to be wary of planting any bramble fruit. Actually, I guess I should say thanks to Mr Burbank again, this time without the cynical note. At least I don't have removing raspberries and blackberries to do.

Re-reading this thread sent me out to my blueberry patch just now, where I removed dried blueberries that I had not bothered to harvest. I don't know why the birds leave my blueberries alone, but I am very grateful that this is so.

We also grow four vines of table grapes. I'll have to keep an eye on those. The birds and squirrels generally eat what we do not so we may be safe there. I do hope so. The grapes taste way better than anything I can buy.

The only other berry plant growing here is the large Persian mulberry tree that came with the house, probably planted in the 1940's by the original owner. The fruit is amazingly tasty, but with the size of the tree we harvest only a fraction of it. So far there has been no infestation that I can see. To be honest, I do not think my DH would ever consent to its being removed. He just loves this tree and its fruit. I do, too.

Our other fruits are several apples, a fig, a persimmon, a couple of pomegranates, two pluots, two apricots, two plums, and a peach. So far no damage to any of those, either. There are some citrus trees too, but drosophila doesn't bother citrus. The skins are too tough.

I'll just have to work on the trap and kill method in case the drosophila shows up. I suppose it is inevitable. There is also Spinosad but with the timing being critical it would be easy to miss the window.

Like others, I have decided to cut back on the size of our orchard. Even the citrus is at risk due to the arrival of Huanglongbing in southern California. No doubt it will show up here before long.

It is truly a sad thing. Harvestman's suggestion that increased worldwide commerce is responsible makes sense to me. I suspect warmer temperatures may contribute as well. But that is the world we live in so we have to deal with it as it is.


This post was edited by rosefolly on Fri, Sep 27, 13 at 14:54

    Bookmark   September 27, 2013 at 2:29PM
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