Black Aphids. Some people say you can squirt them off with the hose (never could figure how this works- won't they simply walk right back up-- or attack the next plant to come their way??) or use my favorite method which is to run your fingers up the stem & squish 'em. Most satisfying!
If you use a systemic insecticide it will take care of them, too.

Uck!!! I have never seen such a bad case of aphids. I am with plantlady2, kill them quick!

EWWW- Black Aphids A La Stemme! That is the worst I've seen too. I think you need a firehose to evacuate that many! Forget the squirt bottle and gentle, but firm, stream of hose water. It's time to turn to chemicals and a systemic discourager (isn't that a nice word as opposed to toxin or pesticide?)

Another strategy would be to companion plant:: those little suckers like beans too, so planting a few bean plants in your dahlia patch might lure them there, as opposed to your flower plants.
On a positive note, the relatively few aphids I've suffered have never seemed to do too much damage to the whole plant. And they dwindle as the season progresses.

Plantlady, I could never figure out how squirting them off worked either, but it seems to do fine. Maybe once they get earthbound they can't climb up again? Or over-wet wings doesn't allow them to fly? I don't know.
See the link for all kinds of tips on various pests.

Here is a link that might be useful: Pest link including aphids

Aphids attach themselves to plants by their mouths and when a stream of water hits them it tears them and their mouths off the plant

Would it be cruel of me to say "GOOD!" to the above info?
Thanks for passing that on Welltraveled.

I use a insecticidal spray, and after a bit I hose that off. I've noticed that if the spray is left on(insecticidal soap) it tends to burn the leaves. Also I use slug/snail bait which kills earwigs too.

Yes-the bugs are REALLY BAD this year. I've also seen the little white moths/flies on the dahlias! ARGH!

Thanks for all the advice.

My wife enjoyed the smooshing the little buggers. We washed them off, but they keep coming back. I think we're on to a spray. Weirdest thing is that there are 2 other dahlias within 3 feet of the plant that are perfectly clean of aphids.

I could suggest Lady Bugs if you all can afford them...I did that one year. At $7 a bag, and 7-8 bags-PRICE-EE! But Lady bugs I did, and it appears they have "cycles." They ate like crazy-follow instructions -what to do when they are released-and then they seemed gone.

I have noticed a few this year haveing a feast. I bought them at the local Northwest Seed and Pet store. The store guarantees the number of bugs in the bag, but NOT the number of ALIVE bugs.

Its not hard to do, if you can do it.

Now I'm using an insecticidal soap. I spray, leave on for a bit, rinse off. If I didn't -which I have forgotten-then the soap tends to brown the edges of the leaves. I just spray the plant off with a fine spray, just strong enough to rinse it off.

Thanks for your time!

tc

I started squishing the aphids by using Plantlady2's method a few years ago. Just running your thumb and finger up and down the stock. Last year I had 2 plants that had a few. This year I have found none as of yet. I also feed tons of birds and I see the birds sitting on the dahlia plants sometimes. I think they do a good job of keeping the aphid population down. I also have lots of little green tree frogs in the dahlias. We have a well and I don't use cemicals.

Hi Rick, I live north of you in snohomish county. You do want to get rid of them quick before they spread to your other dahlia plants. I don't like using insecticides so I get a bucket of warm sudsy water (dishwashinging liquid works just great), and wash it up and down the stems and them leave some of the suds on, doesn't seem to hurt the dahlias but leaves the stems sticky and the aphids don't like it -- be sure and check under the leaves too, they don't just hang out on the stems. Happy hunting!