Blight on Euonymus

#1 · 9th August 2023, 12:43 pm

Blight on Euonymus

#2 · 14th August 2023, 9:40 am

Quote from Lee Garden Ninja on 14th August 2023, 9:40 am
Hi @simon_ih

Thanks for your comment about the small white insects or scales on your Euonymus shrub.

The quick answer is that you have an Euonymus scale. A form of insect that can suck the life out of your shrub slowly causing damage and a lack of vigour.

Euonymus scale (Unaspis euonymi) is a type of scale insect that specifically infests plants in the Euonymus genus. Scale insects are small, immobile pests that attach themselves to the stems, leaves, and branches of plants, feeding on the plant's sap. They are called "scales" due to their protective, waxy covering that resembles a tiny scale or shell. That's the white things you can see on your photo. See below for a healthy Euonymus plant.

Euonymus scale can be a significant pest for Euonymus plants, which are commonly used as ornamental shrubs in gardens and landscapes.

What does Euonymus scale do to the plant?

The infestation can cause:

Yellowing of leaves

Stunted growth

Plant decline if left untreated ie lack of vigour and susceptibility to disease.

How to spot Euonymus scale?

The scales themselves appear as small, flat, oval-shaped bumps that can range in colour from light brown to dark grey.

How to fix Euonymus scale

Managing Euonymus scale infestations typically involves a combination of cultural, mechanical, and chemical control methods:

1. Cultural Practices: Maintaining healthy plants through proper watering, fertilization, and pruning can help prevent stress that makes plants more susceptible to pests.

2. Mechanical Control: You can manually remove scales by gently scraping them off with a soft brush or cloth. This is most effective for smaller infestations.

3. Horticultural Oils: Applying horticultural oils, such as neem oil, can suffocate the scales by disrupting their protective covering. These oils need to be applied when the plant is dormant or during specific stages of the scale's life cycle. Do check out my guide on why neem oil should be avoided or at least used with the full knowledge of it here.

4. Insecticides: If the infestation is severe, insecticides may be necessary. It's important to choose insecticides that are labelled for scale control and follow the instructions carefully. Systemic insecticides can be applied to the soil, taken up by the plant, and ingested by the scales when they feed. Though care must be taken with insecticides as they can have a harmful effect on other wildlife and the food chain. So always consider this as a last resort Simon.

5. Biological Control: Natural predators such as ladybugs, lacewings, and parasitic wasps can help control scale populations. Encouraging a diverse ecosystem in your garden can promote the presence of these beneficial insects.

Hope that helps!

Lee

Hi @simon_ih

Thanks for your comment about the small white insects or scales on your Euonymus shrub.

The quick answer is that you have an Euonymus scale. A form of insect that can suck the life out of your shrub slowly causing damage and a lack of vigour.

Euonymus scale (Unaspis euonymi) is a type of scale insect that specifically infests plants in the Euonymus genus. Scale insects are small, immobile pests that attach themselves to the stems, leaves, and branches of plants, feeding on the plant's sap. They are called "scales" due to their protective, waxy covering that resembles a tiny scale or shell. That's the white things you can see on your photo. See below for a healthy Euonymus plant.

Euonymus scale can be a significant pest for Euonymus plants, which are commonly used as ornamental shrubs in gardens and landscapes.

What does Euonymus scale do to the plant?

The infestation can cause:

Yellowing of leaves
Stunted growth
Plant decline if left untreated ie lack of vigour and susceptibility to disease.

How to spot Euonymus scale?

The scales themselves appear as small, flat, oval-shaped bumps that can range in colour from light brown to dark grey.

How to fix Euonymus scale

Managing Euonymus scale infestations typically involves a combination of cultural, mechanical, and chemical control methods:

1. Cultural Practices: Maintaining healthy plants through proper watering, fertilization, and pruning can help prevent stress that makes plants more susceptible to pests.

2. Mechanical Control: You can manually remove scales by gently scraping them off with a soft brush or cloth. This is most effective for smaller infestations.

3. Horticultural Oils: Applying horticultural oils, such as neem oil, can suffocate the scales by disrupting their protective covering. These oils need to be applied when the plant is dormant or during specific stages of the scale's life cycle. Do check out my guide on why neem oil should be avoided or at least used with the full knowledge of it here.

4. Insecticides: If the infestation is severe, insecticides may be necessary. It's important to choose insecticides that are labelled for scale control and follow the instructions carefully. Systemic insecticides can be applied to the soil, taken up by the plant, and ingested by the scales when they feed. Though care must be taken with insecticides as they can have a harmful effect on other wildlife and the food chain. So always consider this as a last resort Simon.

5. Biological Control: Natural predators such as ladybugs, lacewings, and parasitic wasps can help control scale populations. Encouraging a diverse ecosystem in your garden can promote the presence of these beneficial insects.

Hope that helps!

Lee

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#3 · 15th August 2023, 4:48 pm