Skip to content
Pocket Botanist
Get the app

Guascas · Galinsoga parviflora

What are these spots on my Guascas leaves?

Guascas can sometimes develop a white, dusty coating that looks like flour. This is typically powdery mildew, a common fungal issue for this plant.

Not sure it's this? Check a photo of your plant for free

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

Check these first

  1. Look closely at the undersides of the leaves.
  2. Check for sticky residue on the stems.
  3. Observe if the white spots rub off easily.

Likely causes

  1. Powdery mildew

    Most likely

    How to tell: A white, powdery substance appears on the surface of the leaves.

    What to do: Improve air circulation around the plant by spacing it away from others. You can wipe the leaves with a damp cloth or use a mild neem oil spray.

  2. Aphids

    Possible

    How to tell: Tiny green or black insects cluster on the undersides of leaves or near new growth.

    What to do: Wash the pests off with a gentle stream of water. If they persist, use insecticidal soap once a week.

Pests on other plants

Find out what's wrong with your guascas

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.

Download on the App StoreGet it on Google Play

When to worry

If the white coating covers most of the leaves, the plant will struggle to photosynthesize. Treat it immediately to save the plant.

Stopping it coming back

Water at the base of the plant to keep the foliage dry and ensure good airflow.

Guascas: pests? Check yours with a photo

Every plant is a little different. Take a photo of your guascas 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.

Download on the App StoreGet it on Google Play

Get the app · Or check it from a photo now, free

Questions people ask

Is powdery mildew harmful to eat?
It is best to discard any leaves that show signs of fungal growth before using the plant in cooking.
How do I stop it from spreading?
Remove the infected leaves immediately and keep the plant in a spot with better air movement.

Guides to these causes

More problems with Guascas

Back to the Guascas 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.