It seems that our gardens have been full of aphids this season, and as a result of that, we’ve learned a lot!

Our experience with aphids started when we were growing seedlings in the Olin Greenhouse, and they had managed to feast on our eggplants and some of our peppers! Now, we are working on our eggplants, which still have a few aphids on them (though much less than before!).

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Here’s some ways that we found that has helped decrease and keep in balance the aphid population:

  1. Rain or water the leaves as if there is a heavy rainfall. This will knock off most of the aphids from the leaves, however doesn’t entirely kill them – it just manages to get them off of the plants for a short time.
  2. Hand crush the aphids, which kills many of them. This is a great way of getting rid of large aphid populations, but requires a large amount of labor/manpower.
  3. Introduce predators to aphids: In a greenhouse setting, there is the possibility of introducing predators like ladybugs to aphid infestations. Instead of doing this, we brought the plants outside where they would be exposed to natural predators, rain, and our supervision. Doing this worked quite well, and got off a large portion of the aphid infestation, however, there were a few plants with aphids when we checked the eggplants today, so we squashed them. The pictures help to show where to find aphids, and how to crush them.

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Aphids are usually found on the undersides of leaves or newer leaves because they like the most tender parts of leaves. They are little green bugs the size of a small freckle. Since they are so small, you’d think that they are hard to find, however, they usually stick together, so look for a spread of little green freckle-size bugs on the undersides of your leaves. You may find a few white-looking things among the green. These are the dead skin/shells of the aphids that they have outgrown.

Ants are well known for “farming” Aphids, so one way of preventing aphids is by preventing ant mounds.¬†Aphids eat the tender leaves, and leave a residue called honeydew, which if left on the plant, can cause fungal infections. The ants love to eat the honeydew, sothey are driven to clean the dead aphid shells out, helping to prevent disease from spreading to the aphids, and giving the aphids more room to do their work. Ants, similar to farmers, try to keep out predators of their produce/work. When a ladybug crawls onto a leaf, ants will defend their population of aphids, fighting the ladybug, biting at the ladybug’s legs, or trying to drive it away. Here is an awesome video showing this ant-aphid-ladybug relationship, and the conflict that happens at the confluence of all three.

Another way to prevent aphids is by planting “bait” plants that the pests will go to, and leave the rest of your garden alone – such as nasturtiums and marigolds. We will be planting rows and pockets of marigolds and nasturtiums all around the garden!

If you have any questions, or anything to add, we’d love to hear it!