African mallow shrubs, also known as Anisodontea capensis or Hibiscus acetosella, are popular ornamental plants prized for their vibrant foliage and beautiful flowers. However, like all plants, African mallow shrubs are susceptible to pests that can damage their health and appearance. As a gardener, it’s important to be able to identify and treat common African mallow shrub pests in order to maintain the health and beauty of these plants.

In this comprehensive guide, we will explore some of the most common pests that target African mallow shrubs, how to identify them, and effective treatment options.

Aphids

Aphids are small, soft-bodied insects that can appear green, black, brown, or pink in color. They tend to be found on the undersides of leaves and stems, where they pierce the plant tissues and suck out sap. An aphid infestation can cause leaves to curl, distort, or turn yellow.

Identification

• Small (1-3mm) pear-shaped insects clustered on stems and undersides of leaves
• Varied colors including green, black, brown, pink

Treatment

• Blast plants with water to dislodge aphids
• Apply insecticidal soap or horticultural oil sprays
• Release natural predators like ladybugs, lacewings, syrphid flies

Spider Mites

Spider mites are tiny 8-legged pests related to spiders. They are difficult to see with the naked eye but leave behind telltale webbing on infested leaves. Feeding by spider mites causes stippling, yellowing, and bronzed foliage.

Identification

• Webbing visible on undersides of leaves
• Stippling and mottling damage on foliage
• Tiny (0.5mm) size, oval shaped mites

Treatment

• Apply insecticidal soap or horticultural oil sprays
• Use a strong stream of water to dislodge mites
• Release predatory mites to consume spider mites

Whiteflies

Whiteflies are small, moth-like insects that congregate and feed on the undersides of leaves. Their feeding causes foliage to yellow and leaves to drop prematurely. Whiteflies secrete sticky honeydew which leads to black sooty mold growth.

Identification

• Tiny white moth-like insects flying around plants when disturbed
• Sticky honeydew secretions on leaves
• Sooty black mold on leaves

Treatment

• Apply horticultural oil or insecticidal soap sprays
• Use yellow sticky traps to capture adults
• Release parasitic wasps to parasitize whitefly nymphs

Scale Insects

Scale insects are small, immobile insects that attach themselves to stems and leaves to feed on plant sap. They secrete a protective waxy coating that resembles fish scales, making them difficult to control. An infestation can lead to yellowing foliage, stunted growth, and plant decline.

Identification

• Waxy bump-like coating on stems and leaves
• Yellowing foliage and stunted growth
• Ants crawling on plants as they “farm” honeydew secretions

Treatment

• Apply horticultural oil or insecticidal soap sprays
• Gently rub scales off with cotton swab dipped in alcohol
• Release parasitic wasps or ladybugs to consume scale insects

Caterpillars

Caterpillars are the larval stage of moths and butterflies They chew on foliage and can cause extensive defoliation damage if not controlled. There are many species of caterpillars that can feed on African mallow shrubs

Identification

• Chewed holes in leaves, buds, and flowers
• Presence of green, brown, black caterpillars on plants
• Caterpillar droppings around base of plants

Treatment

• Hand pick caterpillars off plants
• Apply Bacillus thuringiensis (BT) or spinosad sprays
• Use pheromone traps to capture and disrupt adult moths

Mealybugs

Mealybugs are odd looking pests that appear as small white blobs covered in a powdery wax coating. They extract plant sap through their piercing mouthparts. Mealybugs secrete a sticky honeydew that can lead to sooty mold growth.

Identification

• White cottony wax covering body
• Clustered colonies in leaf axils and on stems
• Presence of black sooty mold
• Ants crawling around plants

Treatment

• Use a strong jet of water to dislodge mealybugs
• Apply insecticidal soap or horticultural oils
• Release parasitic wasps or lacewings to control mealybugs naturally

Common Diseases of African Mallow Shrubs

In addition to insect pests, African mallow shrubs are also susceptible to various fungal diseases that can affect their health and appearance. Let’s go over some of the most common diseases to look out for.

Powdery Mildew

Powdery mildew is a fungal disease that presents as white powdery growth on the leaves and stems of plants. It thrives in warm, humid conditions. Infected foliage becomes distorted and turns yellow before eventually dropping from the plant.

Identification

• White powdery coating over leaves
• Distorted, curled leaves
• Yellowing and defoliation

Treatment

• Apply fungicides like myclobutanil, propiconazole or neem oil
• Provide good air circulation and avoid overhead watering
• Remove and destroy infected plant debris

Leaf Spot

Leaf spot diseases cause small, circular brown spots to form on foliage. The spots may have yellow halos and may eventually turn the entire leaf brown. Leaf drop can occur in severe infections.

Identification

• Small brown spots on leaves, sometimes with yellow rings
• Leaves turning entirely brown
• Premature leaf drop

Treatment

• Apply fungicides like chlorothalonil, mancozeb or copper sprays
• Remove and destroy infected leaves
• Avoid overhead watering to limit spread

Root Rot

Root rot is caused by fungi that thrive in wet, poorly drained soils. Infected plants exhibit stunted growth, wilting, and yellowing leaves. The roots appear brown, mushy, and easily slough off.

Identification

• Stunted growth and poor vigor
• Wilting and yellowing leaves
• Brown, mushy roots
• Sudden plant decline

Treatment

• Improve drainage and avoid overwatering
• Apply fungicides like metalaxyl to protect roots
• Remove and destroy badly infected plants

Botrytis Blight

Botrytis blight leads to a fuzzy gray fungal growth on flowers, leaves, stems, and buds during cool, humid weather. It quickly causes blossoms and foliage to turn brown, wither, and die.

Identification

• Gray, velvety mold on flowers, leaves, and stems
• Browning, withering, and dying of plant tissues
• Sporadic infections during cool, wet periods

Treatment

• Apply fungicides like chlorothalonil, myclobutanil, or neem oil at first sign
• Improve air circulation around plants
• Promptly remove infected plant debris

By learning how to recognize common African mallow shrub pests and diseases, you can quickly take action to mitigate any issues before lasting damage occurs. Monitor plants routinely for early signs of problems. When pests or diseases are spotted, implement integrated pest management utilizing a combination of organic sprays, beneficial insects, and proper cultural practices. With quick identification and treatment, your African mallow shrubs will continue thriving season after season.