Heliotrope Plant Bugs

Heliotropium arborescens or heliotropes are flowering plants that grow between 18 and 36 inches tall. They produce showy purple, blue or white blossoms depending on the variety. Heliotropes prefer full sunlight, nutrient-rich soil and ample water. They are generally hardy and suffer from few serious pests, according to Cheryll Greenwood Kinsley at the Washington State University Whatcom County Extension, but several kinds of bugs occasionally feed on the leaves and sap.

Spider Mites

Tetranychus urticae, or twospotted spider mites, are eight-legged, oval-shaped arthropods around 0.02 inches in length. They have a prominent dark spot on each side of their greenish-yellow, orange or brown bodies. Twospotted spider mites insert their needle-like mouthparts into the undersides of heliotrope leaves and drain juices from the plant. The leaves develop yellow stippling in areas where the pests have been feeding. The affected foliage eventually turns yellow or brown, dies and falls from the plant. Spider mites also spin unsightly webs on foliage. Homeowners control these bugs with miticides, insecticidal soaps or horticultural oils.

Mealybugs

Mealybugs range in size from 0.03 to 0.15 inches long. Their flattened, oval-shaped, segmented bodies are covered in a layer of grainy white wax. These bugs stunt plant growth by draining sap from the foliage. They also release a sticky-sweet liquid called honeydew that drips on the surrounding foliage. A black fungus called sooty mold grows on the honeydew. Some parasites such as lacewings and lady beetles control mealybug populations naturally by feeding on the pests. Homeowners can also reduce control mealybug infestations by using traditional chemical insecticides.

Aphids

Aphids are small, pear-shaped bugs that vary in color from red to black, yellow or green depending on what they have been eating. They have long antennae, long legs and a pair of long, narrow tubes called cornicles that extend from the rear parts of their bodies. Aphids drain sap from heliotrope foliage and leave sticky honeydew on the leaves. Some aphids also transmit viruses from one plant to another. Aphids do not cause significant damage in small numbers. You can dislodge the bugs by spraying the plants with a steady stream of water. Natural enemies such as parasitic wasps, lady beetles and lacewings control aphid populations.

Whiteflies

Whiteflies are small, moth-like bugs that range in size from 0.1 to 0.06 inches long. They have yellowish bodies and four whitish wings. Many whiteflies are covered in a layer of powdery, whitish wax. These bugs, which are closely related to mealybugs and aphids, drain sap from heliotrope plants and leave honeydew deposits on the foliage. Some species also transmit viruses. Infested plants may have stunted growth, yellowed leaves or leaf loss. Homeowners control infestations with natural enemies as well as with insecticidal soaps, horticultural oils and traditional insecticides.

References

• Michigan State University Extension: Heliotropium arborescens--Heliotrope
• North Carolina State University: Annual Flowers -- Heliotropium arborescens; Erv Evans
• Washington State University Whatcom County Extension: Heliotrope; Cheryll Greenwood Kinsley
• Google Books: Diseases and Pests of Ornamental Plants; Pascal Pompey Pirone
• Texas AgriLife Extension: Heliotropium arborescens; Michael A. Arnold; 2006
• University of Florida IFAS: Twospotted Spider Mite

Resources

• University of Illinois Extension: Twospotted Spidermite
• Iowa State University Extension: Mealybugs -- A Common Household Pest; Mark Shour; February 27, 2004
• University of California Statewide Integrated Pest Management Program: Citrus Mealybugs
• University of Rhode Island Landscape Horticulture Program: Aphids
• University of Missouri Extension: Managing Whiteflies; Bruce A. Barrett; June 2010
• University of California Statewide Integrated Pest Management Program: Whiteflies