Year of the Aphids

Ants & Aphids on Oleandar Blossom

This year was mostly a great growing season for our garden. We got lots of beans, squash, tomatoes, and other goodies.

However, this year was also the year of aphids.

At left is a blossom on a red oleandar that I planted a few weeks before that photo was taken.

The ants are farming the aphids. That is, they herd and protect the aphids. In return, the aphids suck the plant’s sap and the ants carry off the waste product — the aphid poop — to store away in their nest for future feasting.

Two species acting symbiotically to irritate the hell out of me.

Ants Herding Aphids on Oleander

If this were the only infestation of this kind, I would be concerned that I had chosen a location for the plant that was sub-optimal and, thus, led to weakness that made the plant susceptible to such an attack.



Black bean aphid  (Aphis fabae)

But, not in this case. This is not the only massive infestation of aphids that I have seen this year!

The community garden was also plagued with aphids. And by plagued, I mean plagued.

This is a closeup of the blossom of a long bean plant. At a distance, the vine looked black because the aphids were this thick over the entire plant.

If you look closely at that photo, there are a handful of parasitic bugs attacking the aphids. Unfortunately, nowhere near enough to quell the infestation. The only solution was to remove the plant in its entirety.

Oddly, they only attacked some of the bean plants. No idea what made one plant more attractive than the next, given that the beans were in the same soil and climbing the same trellis.



8 Responses to “Year of the Aphids”

  1. annbb says:

    Aphids only appeared on nasturtiums after I’d brought them home. The absolute bane of my existence (and everyone else’s) this year in our CG were Mexican beetles. I hate them. They look like orange ladybugs. They ate all the foliage and where they were done with that, started in on the beans. I really really hate them.

  2. Peter Bierman says:

    Do you have any luck with ladybugs? My dad used to buy them to control aphids.

  3. bbum says:

    Ladybugs work great for a reasonable sized infestation. For infestations like the bean plant, elimination of the plant is the only way. The plant is already pretty much dead anyway, given the trauma. In the case of the oleander aphids, the ants will defend the aphids to the point where the ladybugs will typically head to easier hunting grounds.

    I find that a soapy water solution generally works to disrupt the cycle. Or grab one of the organic friendly insecticide soaps at the hardware store. It is pretty innocuous stuff, containing an extract that kills the bugs but doesn’t harm the plant (nor humans).

  4. Luc J says:

    I’ve seen the ants attack the ladybugs to protect the aphids on my roses. But the roses do survive when help arrives on time.

    I use insecticide most of the time, will try the soapy water next time.

  5. Thomas Ferraro says:

    We had an aphid infestation in bed of nasturtiums and sunflowers (northern NJ) that looked almost as bad as you pictured. I started pulling off the worst leaves, but realized the entire plants would soon be bare. A massive dose of ladybugs did the trick. Our girls loved spreading them around. IANAE (I am not an entomologist), so don’t know what kind of aphids they were, but did not see any ant activity.

  6. chris says:

    you can actually try using a hand held vacuum on low setting and it will suck most of them off the plant. Do it enough times and the numbers will get down to the level where ladybugs will clean up the rest.

  7. martin says:

    the aphids that attacked your bean are called “Black Bean Aphids” and they are specialised in that particular plant (as the majority of aphids are) and therefore don’t feed on other plants. you can try to tackle that issue with a mix a natural enemies. ladybugs are of great use, however, they only will survive/stay in your garden if there are “enough” aphids (they need a high “pest density”). there are also other natural enemies, such as hoverflies and lacewings, that are “satisfied” with relative few aphids and therefore can be used to keep the pest population down before it really becomes a problem. you can buy them in garden stores and on the internet.

    when using natural enemies it is important to also have some flowering plants that additionally provide these animal a nectar and pollen source. only in this way you will be able to establish a permanent population of natural enemies in your garden. suitable plants for that are:

    Buckweed
    Corn Marigold
    Lacy Phacelia
    Bishop’s Flower
    Gypsophila

  8. martin says:

    …i meant “buckwheat”

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