Tiny Black Bugs on Dahlias: How to Identify and Get Rid of Them

One of the most common flowers grown in home gardens is the dahlia. Their bright colors and unique shapes make them stand out in any landscape. But these pretty flowers also attract tiny black bugs that can hurt the plants. To grow healthy plants and get the most flowers, you need to learn how to spot and get rid of these common dahlia pests.

What Are the Tiny Black Bugs on Dahlias?

There are two main tiny black bugs that feed on dahlias

Aphids

Aphids are small, soft-bodied insects that suck sap from the leaves and stems of plants. They come in a variety of colors, including green, black, brown, red, and yellow. Aphids secrete a sticky substance called honeydew that attracts other insects and can lead to the growth of sooty mold fungus.

On dahlias, aphids tend to cluster on the undersides of leaves and at the tips of stems. They cause distorted growth, yellowing leaves, and stunted plants. Aphids can also spread viral diseases.

Thrips

Thrips are tiny, slender insects that rasp and suck juices from leaves, buds, and flowers They are usually black or brown in color. Thrips damage shows up as silvered or dried areas on leaves and discolored flowers They can stunt plant growth and reduce flowering.

Dahlia plants have tight buds and other cracks where thrips like to hide. Their feeding results in deformed blooms with dark scarring. Heavy infestations can cause flowers to drop.

How to Identify Tiny Black Bug Damage on Dahlias

Watch for these common signs of tiny black bug infestations on your dahlias:

• Distorted, curled, or yellowing leaves
• Stunted plant growth
• Sticky secretion on leaves and stems
• Sooty mold fungus on leaves
• Wilting or dropping flowers
• Scarred, discolored, or deformed blooms
• Small black insects clustering on undersides of leaves and on stems

Check all parts of the dahlia plant closely, especially the undersides of leaves and inside unopened buds, to spot the tiny pests. Use a magnifying glass to inspect for small black specks that move around quickly.

Effective Ways to Get Rid of Tiny Black Bugs on Dahlias

As soon as you see aphids, thrips, or other small black bugs, you need to act quickly to prevent damage. Here are some effective organic control methods:

Remove by Hand

For light infestations, manually remove the bugs by spraying plants with a strong blast of water or wiping them off with a damp cloth. Check plants daily and crush any bugs you find. Be sure to get underneath leaves and into crevices.

Use Horticultural Oils and Insecticidal Soaps

Coating plants with lightweight horticultural oils or insecticidal soaps suffocates many soft-bodied insects. For best results, spray all plant surfaces thoroughly, especially the undersides of leaves. Apply weekly until pests are under control.

Attract Beneficial Insects

Aphids, thrips, and other small insects can be eaten by ladybugs, lacewings, and parasitic wasps, which are nature’s killers. Plant pollen and nectar-rich plants nearby, like dill, fennel, and cosmos, to attract these good bugs. Avoid pesticides that would kill the good bugs.

Apply Organic Pesticides

For heavy infestations, apply organic insecticides derived from plants like neem oil, pyrethrin, or spinosad. Always follow label directions carefully. Repeat applications may be needed to fully eradicate pests. Be aware these products may also kill beneficial insects.

Control Ants and Remove Honeydew

Ants often herd and protect aphids, so getting rid of ants can reduce aphid numbers. Prune away stems or leaves covered with sticky honeydew secretions since this can attract more bugs.

Remove Damaged Growth

Prune off badly infested leaves, stems, and flowers. This removes pests and egg clusters and prevents spread. Put pruned parts in sealed bags and dispose of them. Sterilize pruners between each cut to avoid spreading pests.

Use Row Covers

Covering plants with fine mesh fabric row covers blocks access by winged aphids and thrips. Install covers in early spring before pests are active. Be sure to allow space for growth and airflow.

Control Weeds

Weeds around the garden harbor pests and diseases. Pull weeds regularly to eliminate places where bugs can overwinter.

Prevent Tiny Black Bugs on Dahlias

Good cultural practices can help avoid problems with aphids, thrips, and other tiny pests:

• Inspect plants frequently and control bugs early before they multiply
• Use drip irrigation to keep foliage dry
• Avoid excess nitrogen fertilization that produces succulent growth attractive to pests
• Clean up fallen leaves, blooms, and other debris around plants
• Rotate dahlia locations each year to prevent pest buildup
• Cover young transplants with floating row covers

Selecting resistant dahlia varieties can also reduce pest problems. Ask your local nursery for recommended resistant cultivars for your area.

Controlling tiny black bugs is vital for growing strong, flowering dahlias. Check plants often and take quick action at the first sign of infestation. Combining good cultural practices with targeted organic treatments will keep your dahlias gorgeous and pest-free all season.