SWD - Is this it on Blackberry

Are these hair like things coming out of the center of some of the individual fruits (drupes ?) Evidence of SWD?

I have been picking Blackberries each morning and evening just as they turn black. Wish I could trust to leave them on a little longer to sweeten but am paranoid.

It is amazing how quickly they turn color from morning to evening and overnight.


those are parts of the flower, they usually fall away. Harmless, google SWD, you will see countless pictures of the larvae, cut open a few and look closes for anything moving. There are other tests, a salt water one, as well as sticky traps to monitor activity.

Take a berry you suspect has it and squish it in your fingers lightly and you’ll see them squirming around in the juice.



I’ve been eating them and freezing the excess for later use in jam or smoothies. I have limited myself to the firm ones fearing anything that was even remotely softer.

The good thing is that I like tartness although some added sweetmess would be grand.

BTW, have we come to a definitive spray modality with a short PHI for SWD in berries?


Spinosad per my brands label recommends 3-4 days PHI, that’s what I’ve been using.


You know the concept of " out of sight out of mind".

I have been popping them into my mouth as long as they are firm or pretty firm. Afraid that if I open one up and see a squirmie, in a berry that I would otherwise eat, it might gross me out.

But it these things that I see are only part of the flower I will take a chance and leave a few on the cane a little longer and see how long it takes them to sweeten up enough before they get hit , if at all.

Also, as I asked Moley, did we come to some kind of a consensus of a short PHI spray for these?


Better to see a squirmie than to feel a squirmie!!

Malathion, Mustang Max and Delegate. Malathion and Mustang smell terrible. Mustang is Restricted use. Malathion is common and cheep, but not all brands are labeled for blackberry.


T H A N X for that vision!:sweat: :slight_smile:


Mustang is in use out here commercially, I didn’t see a single fly in a local treated field.

If you have SWD in your blackberry patch, it will be obvious, these are not secretive insects. The first evidence on fruit is typically the collapsed drupelet, caused by the female fly’s piercing. Drupelets on the shoulder (stem end of berry) usually get it first as they ripen and soften first. These berries may prematurely fall.

Easy test for SWD is to leave a fully ripe and slightly smooshed fruit on the ground in the shade. The flies do not spook if you approach with a little caution, and can be seen on the berry. I use these as “bait” berries and spray them with a flying insect spray; sometimes a dozen can be killed at once. Am also using vinegar traps and Spinosad.

Suspect fruit can be put in the fridge and quarantined for several hours; the larger larvae will exit the fruit and can be plainly seen.

If you thought pistil remnants were SWD evidence, the fly truly has you spooked!


Several U-pick growers here had SWD problems a few years ago because they did not notice them until it was too late. Most fruit flies look very similar, but SWD is the only one that has the ability to penetrate unblemished and sound fruit and lay eggs.

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The OP did not mention other fruit flies in his blackberries. SWD could certainly surprise if newly among other established fly populations. I used to have black fruit flies on my fallen and over-ripe berries. The year SWD appeared, I have not seen the black flies since, not sure why.

I got SWD last year in some cherries and had to quit selling them. Similarly w/ blackberries last year.

This year been much more diligent with sprays. For me they were pretty obvious last year, lots of gnats flying around. Berries crumbling/melting from larva. The berries also taste horrible if they have larva.

The guidelines I’ve read for SWD are weekly sprays if no rain. With rain reapply some insecticide.

I noticed Moley mentioned his Spinosad has a 3-4 day PHI. The commercial product (Entrust) has a 1 day PHI, but it is very very expensive for even a quart.

Blueberry is right. Malathion, Mustang and Delegate are considered the big guns against this pest.

I am using Monterey Garden Insect Spray

I also add a bit of sugar, maybe a TB or two