Here what I normally do: I leave them alone and soon the LADY BUGS arrive.
Seriously ... andI they'd mate all day long and soon I have lots of babies lady bugs that eat the aphids.
If you keep removing the aphids, the lady bugs will never come.
If you want to try to get rid of them, the key is to keep after them. No matter what you do, if you do it once and then wait a while they'll be back because you always miss one or two and they reproduce at the speed of light. I typically just hose them off of my plants, but I'll do it every day or two for a while. Milkweed aphids are persistent and I haven't had as much luck getting rid of them even if I keep after them every day, but all the other aphids I've been able to control them that way. You can also use insecticidal soap if just hosing them off isn't doing enough. Even with it though you need to keep after them.
Forgot to mention... I tried lady bugs -- for some reason, they just walk right by the aphids. (and I BOUGHT the lady bugs!).
How much soap should I put in the water? I tried 1 tsp in about a quart... useless.
How would I recognize them as milkweed aphids?
On peas I have green aphids, on brassicas (mostly cabbage, but also broccoli and cauliflower), I have white aphids. The green ones fall off very easily when squirted, but they are back later in the day. The white ones require a firehose to get them off... and they are actually killing plants.
I'm so frustrated... I wonder if it is so much worse this year because our weather has been so cool?
Usually I will mix a tbsp of Neem oil in a tbsp of Dawn dishwasher per gallon of water and spray it thoroughly. I sometimes will add Fish Emulsion in the prescribed dosage with it for some foliar feeding at the same time. Please make sure you do it just before sunset, otherwise you will burn the leaves or injure them. I have been there and done that.
I have bought ladybugs and they do take care of the aphids. It does not mean that ladybugs will just go on and grab every aphid there is. It is biologic control, so it is not perfect but as close as you can get to natural balance, which is really perfection in itself.
The milkweed aphids are orange and only bother plants in the milkweed family so that's definitely not what you have on your peas, broccoli, etc. As far as the soap--I prefer to buy insecticidal soap vs trying to make my own--that way I know the concentration is right. Your tablespoon in a quart is may not be enough, plus dish "soaps" don't actually have real soap in them--they are synthetic detergents and I'm not sure those are as effective as real soap would be. I haven't found the insecticidal soap to be any more effective than the hose in controlling the aphids, but if you have fragile plants that can't take a strong blast from the hose then it's a good option.
As far as why they're worse this year--I've had no luck predicting which years are going to be worse. I'm not having problems with them up here this year, but I have had issues in other years. This year even though it's been cool and wetter than usual I've been having some spider mite problems which I haven't had issues with in hotter drier years. Go figure!
Yes, a multi-approach seems best. Also I know that over-fertilizing can lead to more aphids because of too much lush growth. Another thing I would try, and I know this sounds strange, is to let your plants dry out slightly (if the rain quits!). Just enought to cause a little bit of stress to the plants. This increases plants' natural resistance to insects and diseases. In some studies this reduces the amount of insect (aphid) damage to the plants and the plants are actually hardier and healthier. Natural resistance is so important in plants health and performance.
Maybe that's why I don't usually have too much trouble with them--my garden is pretty much xeriscape and I'm very stingy with the water. When I do get aphids it's typically on my container plants which get a little more TLC.
Very interesting about your xeriscape garden having few aphids. How about other insect and disease problems? Are they reduced too do you think? I believe that over-watering and over-fertilizing does contribute to these types of problems.
I honestly have very few insect pest problems (knock on wood), and the problems I do have tend to be on my container plants and I have more of those in the winter when everything's crammed together in the greenhouse. In the 5 yrs I've been in this house, I had scale on my Cestrum one year, milkweed aphids on my Tweedia a few times (but they don't bother anything else), and just the other day I found spider mites on my Buddleias (I have no idea why--it's been cold and wet lately which are not their usual conditions!)
I have never yet had to spray an insecticide of any sort in the garden beds--I've just used the hose to knock things off (the scale I also removed some by hand). I never fertilize my garden beds and don't water much. The only problem I really have is gophers and the occasional vole, which unfortunately kill a lot more plants than the bugs would!
I've reduced myself to insecticial soap (organic)...
It's just a hot mess.
Luckily, I am able to harvest (the crop is just beginning).
And I had sent out the word that I was collecting banana peels -- my sister's first grade class made a project out of it! So, now I have about 4 pounds of banana peels... I think I will dry them out and powder them... all the google research swears it will work...
If they're whitefly, try worm castings--work some into the soil around the base of your plants, or make a tea out of it and spray it on the plant (or even better, do both). I've never had whitefly problems, but I've seen people swear by worm castings for taking care of them.
I'm not sure but it's worth looking. I can't remember if I've seen them there or not. I know there are places you can buy them online if you can't find them locally but it's worth calling around to some local places first. Orchard Nursery in Lafayette or Sloat in Danville would be two other places not too far from you that would be worth checking.
Let me know how the worm castings do with the white flies. I also hear that soapy water will work but that you have to be diligent about applying every few days because the soap only kills the adults. I have not had experience with white flies yet.
My proven and undesirable way to control aphids here in Montana and have proven the best and easiest way is ---------------HORNETS. My wife last year without me knowing it sprayed our V. creeper for white flies and killed almost all of them and this year I am aphid attacked for the first time in years. I always had the nests near the doors moved and let 25 to 50 nests to be active. We are stung once or twice a year but aphids were never a problem here. The wasp was friendly and unless attacked or bothered never bothered us. My wife is now a believer in my theory because aphids are thick this year and will only be eliminated with the gradually building colonies that are appearing. We only have 2 paperwasp and three yellowjackets so far. They are my friends with aphids, and any worm that crawls on plants.
Wasps love aphids and also scale insects. I had a pipevine completely covered with scale insects. The wasps moved in and made many meals of the scale and completely cleaned the vines. I've also seen them eating cabbage loopers and other caterpillar pests.
Aphids are bad here this year, we have a gazillion ladybugs, many wasps and other beneficials and they just can't keep up with the aphids. I don't overfertilize and we've had two rains since last October. We do irrigate the garden. It's been hotter than usual.
I move the ones at night when they are near a travel area. I have a 2nd story and that is where I hang them in cheeze cloth tacked to the roof. Paper wasps are easy to move and I just bundle up and put the nest in a bag and carry it to my desired location in branches of my swedish aspen.
The aspen just hold them when you lay them in with a pulled out branch. Up in my over-hang I just place the nest in the cheeze cloth and Tack it to the wood. They eat through the cheeze cloth and exit in less than a few hours. Then they fix the nest the way they want it.
Yes but know that they will immediately attack so put the cheese cloth around the nest and run with it so the returning wasps don't kill you. I grab the nest run about 30 to 50' and rubber band the top closed and put it in the limbs of my tree where I want it (somewhere untrafficked) then leave. If you are going to put it under an eave I have the nail placed so the cheese cloth can be punctured and hung there.
I found that cilantro/coriander plants attract a lot of tiny beneficial wasps when they are in bloom. Since they are short-lived, you have to succession sow. I first planted milkweed to attract butterflies, but it attracts aphids instead. That turned out to be a good thing - it keeps the ladybugs around.
Ladybugs walking right by the aphids: yes, that is what they do. But they lay eggs nearby and the larva eat the aphids.
Tiny white flies, too: might be more aphids. The first and last stage of aphids is a flying insect that doesn't look like the sap-sucking stages in between.