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Johnsongrass · Sorghum halepense

Why are there bugs on my Johnsongrass?

It is less common for Johnsongrass to have pests, but aphids or spider mites can occasionally show up. Check the undersides of the leaves first to see if you have an active infestation.

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pests on a plant
Photo: Jules Verne Times Two, CC BY-SA 4.0

Check these first

  1. Inspect the undersides of leaves for small insects.
  2. Look for fine webbing near the leaf joints.
  3. Check if the plant is near other infested plants.

Likely causes

  1. Aphids

    Possible

    How to tell: You will see tiny green or black insects clustering on the new growth or stems. They often leave behind a sticky substance called honeydew.

    What to do: Spray the plant with a strong stream of water to knock them off. If they persist, apply insecticidal soap every 5 to 7 days until they are gone.

  2. Spider Mites

    Possible

    How to tell: Look for fine, silky webbing between the leaves and tiny yellow stippling on the foliage. These pests thrive in hot and dry conditions.

    What to do: Increase the humidity around the plant and wash the leaves with water. Use neem oil once a week for 2 weeks if the infestation is heavy.

Pests on other plants

Find out what's wrong with your johnsongrass

The list above covers the usual causes. Pocket Botanist looks at a photo of your actual plant and tells you the likely cause, how serious it is, and what to try first. Identification and a health check are free.

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When to worry

Worry if the leaves start yellowing or dropping rapidly. A few bugs are usually manageable, but a full colony can weaken the plant.

Stopping it coming back

Keep your plant healthy with consistent water and good airflow. Regularly wipe down leaves to remove dust and potential pests.

Johnsongrass: pests? Check yours with a photo

Every plant is a little different. Take a photo of your johnsongrass and Pocket Botanist tells you which cause is most likely, how serious it is, and what to try first. A few checks a day are free. Save the plant and you get care reminders timed for it.

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Questions people ask

Will these bugs kill my plant?
Usually not, but they can stunt growth if left unchecked. Treat them early to keep your plant vigorous.
Can I use household soap to kill them?
Avoid using harsh dish soaps as they can burn the leaves. Stick to insecticidal soap or neem oil for safety.

Guides to these causes

More problems with Johnsongrass

Back to the Johnsongrass guide

This article was generated with AI on from the plant’s care profile and is general information, not horticultural advice. Read about how we build these guides.