Welcome to the Garden Ninja Gardening Forum! If you have a gardening question that you can't find answers to then ask below to seek help from the Garden Ninja army! Please make your garden questions as specific and detailed as possible so the community can provide comprehensive answers in the online forum below.

Welcome to the ultimate beginner gardening and garden design forum! Where no gardening question is too silly or obvious. This online gardening forum is run by Lee Burkhill, the Garden Ninja from BBC 1's Garden Rescue and a trusted group of experienced gardeners.

Whether you are a beginner or an expert gardener, it's a safe place to ask garden-related questions for garden design or planting. If you have a problem in your garden or need help, this is the Garden Forum for you!

Posting Rules: This space is open for all garden-related questions. Please be polite, courteous and respectful. If you wouldn't say it to your mum's face, then don't post it here. Please don't promote, sell, link spam or advertise here. Please don't ask for 'cheeky' full Garden redesigns here. They will be deleted.

If you need a garden design service, please use this page to book a design consultation. I will block anyone who breaks these rules or is discourteous to the Garden Ninja Community.

Join the forum below with your gardening questions!

Ask a Gardening QuestionGardening Questions & Answers: Plant ProblemsStrange brown spots on indoor pla …

Please or Register to create posts and topics.

Strange brown spots on indoor plants

#1 · 23rd May 2023, 10:42 am

Hi there - hoping for a bit of help, I've had these brown spots on my umbrella tree and monstera but I don't know what disease it is and how to treat it. I've spent a fair bit of time wiping the brown spots off time and again, but they always seem to come back. Anyone know what this disease is and how to treat it?

Uploaded files:

#2 · 23rd May 2023, 2:11 pm

Quote from Lee Garden Ninja on 23rd May 2023, 2:11 pm
Hi @acc723

Thanks for your question about what the white or brown spots are under your house plant.

These are actually scale insects that feed off house plants. So let's take a closer look at scale insects and their impact on house plants.

What are scale pests?

Scale pests, also known as scale insects, are common pests that infest house plants and many other types of plants. They belong to the insect order Hemiptera and the family Coccoidea. Scale insects are named for the protective scale-like covering they develop on their bodies, which helps protect them from predators and environmental factors.

How to identify scale insects?

Scale insects or pests can be identified as small, oval or round-shaped insects that attach themselves to the stems, leaves, and sometimes the fruits of plants. Scale insects come in a variety of colours, including brown, black, white, yellow, and even pink or red, depending on the species.

How do scale insects damage plants?

These insects feed by piercing the plant tissue with their mouthparts and extracting sap, which weakens the plant and can lead to stunted growth, yellowing of leaves, leaf drop, and the overall decline in plant health. As they feed, they secrete a sticky substance called honeydew, which can attract other pests like ants and promote the growth of sooty mould.

How quickly do scale insects reproduce?

Scale insects can reproduce rapidly, and infestations can quickly spread to other plants if left untreated. They can be particularly troublesome for indoor plants since the controlled environment indoors can provide favourable conditions for their development. They can spread from house plant to house plant and suddenly infect your entire plant catalogue if you are not careful!

How to get rid of scale pests?

Controlling scale pests typically involves a combination of manual removal and chemical or biological treatments.

Manual removal involves physically scraping off the scales from the plant using a soft brush or cloth.

Insecticidal soaps, horticultural oils, or insecticides specifically formulated for scale insects can also be used to control infestations. Mixing 1/10 washing up liquid and water to then spray on them can help seal the scales causing them to die. But spray with care and avoid the full sun after spraying the leaves as the mixture can burn or discolour the leaves. Neem oil is also an excellent natural deterrent and treatment for scale insects.

Beneficial insects, such as ladybugs or predatory beetles, can be introduced to help control scale populations naturally but this is more suitable for outdoor plants and shrubs.

How to prevent scale insects on house plants

Regular inspection of plants, maintaining good plant health, and proper sanitation practices, such as removing and destroying heavily infested plant parts, can help prevent and manage scale pest infestations in house plants.

If I were you, I'd manually clean these off with a cloth with washing up liquid on, then consider neem oil as a post-clean treatment.

Keep your eyes on it to see if it continues but a full deep cleanse should help!

Happy gardening

Lee

Hi @acc723

Thanks for your question about what the white or brown spots are under your house plant.

These are actually scale insects that feed off house plants. So let's take a closer look at scale insects and their impact on house plants.

What are scale pests?

Scale pests, also known as scale insects, are common pests that infest house plants and many other types of plants. They belong to the insect order Hemiptera and the family Coccoidea. Scale insects are named for the protective scale-like covering they develop on their bodies, which helps protect them from predators and environmental factors.

How to identify scale insects?

Scale insects or pests can be identified as small, oval or round-shaped insects that attach themselves to the stems, leaves, and sometimes the fruits of plants. Scale insects come in a variety of colours, including brown, black, white, yellow, and even pink or red, depending on the species.

How do scale insects damage plants?

These insects feed by piercing the plant tissue with their mouthparts and extracting sap, which weakens the plant and can lead to stunted growth, yellowing of leaves, leaf drop, and the overall decline in plant health. As they feed, they secrete a sticky substance called honeydew, which can attract other pests like ants and promote the growth of sooty mould.

How quickly do scale insects reproduce?

Scale insects can reproduce rapidly, and infestations can quickly spread to other plants if left untreated. They can be particularly troublesome for indoor plants since the controlled environment indoors can provide favourable conditions for their development. They can spread from house plant to house plant and suddenly infect your entire plant catalogue if you are not careful!

How to get rid of scale pests?

Controlling scale pests typically involves a combination of manual removal and chemical or biological treatments.

Manual removal involves physically scraping off the scales from the plant using a soft brush or cloth.

Insecticidal soaps, horticultural oils, or insecticides specifically formulated for scale insects can also be used to control infestations. Mixing 1/10 washing up liquid and water to then spray on them can help seal the scales causing them to die. But spray with care and avoid the full sun after spraying the leaves as the mixture can burn or discolour the leaves. Neem oil is also an excellent natural deterrent and treatment for scale insects.

Beneficial insects, such as ladybugs or predatory beetles, can be introduced to help control scale populations naturally but this is more suitable for outdoor plants and shrubs.

How to prevent scale insects on house plants

Regular inspection of plants, maintaining good plant health, and proper sanitation practices, such as removing and destroying heavily infested plant parts, can help prevent and manage scale pest infestations in house plants.

If I were you, I'd manually clean these off with a cloth with washing up liquid on, then consider neem oil as a post-clean treatment.

Keep your eyes on it to see if it continues but a full deep cleanse should help!

Happy gardening

Lee