Aphids Are Back! 5 Tips for Managing Aphids Organically

Our veggie teaching beds at Zilker Botanical Garden have sprung back to life after the winter storm and a lot of insect activity is starting to happen. Our fall crops like brussel sprouts and cabbages are starting to fade out and are attracting aphids, a small sap-sucking insect that can be found on the underside of leaves. Many insects have freeze-tolerance mechanisms that allow them to survive through freezing temperature.
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Aphids don’t do much damage when there’s only a few around. It takes clusters of them — and there usually are by the time they’re found — to make leaves curl and yellow as they deposit their sticky “honeydew” made from the moisture taken from the plants on stems and on the underside of leaves. If left untouched, this substance turns black with the presence of sooty mold fungus. ​

Aphids on Brussel Sprouts

Lady bugs mating on cardoons

The wonderful staff at Zilker Botanical Garden covered our beds with frost covering before the winter storm and most plants bounced right back. The cardoons were mildly damaged by the storm and they are also attracting aphids. We couldn’t help but notice it had turned into a playground for the lady bug beetles, hover-flies, lacewings and other pollinators. They were also all over our bolting cilantro and mustards in our winter cover crop. These beneficial insects are a natural solution to aphids. It's reported that a ladybugs and lacewings will eat some 50 aphids a day. If you're lucky enough to have these insects in your garden, their larvae will eat their weight in aphids each day.

Here are a few tips on helping control aphids organically and how to attract beneficial aphid loving insects.

1. Add plant diversity to your garden. Here are plants broken down into beneficial, repellant and trap categories. 
   • Attract beneficial insects: Plant clover, mint, dill, fennel, and yarrow. 
   • Natural aphid repellents: Plant catnip, marigold, garlic, chives, leeks, and onion. 
   • Aphid trap plants: Plant zinnias, cosmos, asters, mustards, and nasturtium
2. Plant cover crops. We planted winter cover crops that include Austrian winter peas, rye, mustard, daikon and hairy vetch. The beneficial lady bug beetles, hover flies, lacewings, and birds were all over the blossoms this spring. In the late spring and summer you can plant buckwheat which attracts honeybees, hover flies, soldier beetles, parasitic wasps and parasitic flies.
3. Allow your vegetables to flower or bolt and go to seed because you want to attract beneficial insects and feed the bees. 
4. Remove aphids by hand by spraying water or knocking them into a bucket of soapy water. You can control with natural or organic sprays like a soap-and-water mixture, neem oil, or essential oils. 
5. Buy beneficial insects. If you don’t have diversity in your garden, you can buy some beneficial insects like lady bug beetles at garden stores but it is best to plant the herbs and plants that attract these insects to your garden.

Let us know any tricks and tips you use in the comment section.

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