Great Blue Lobelia (Lobelia siphilitica) is a stunning native perennial plant that produces beautiful blue flowers in late summer and early fall. While this plant is relatively low-maintenance, it can still fall victim to various pests that can damage its foliage and flowers if left unchecked. In this article, we will discuss some of the most common pests that affect Great Blue Lobelia, how to identify them, and the best strategies for treatment.
Aphids
Aphids are small, soft-bodied insects that feed on plant sap by piercing the leaves and stems of plants. They can be identified by their pear-shaped bodies and can appear in a variety of colors such as green, black, brown, or red. Aphid infestations on Great Blue Lobelia can cause stunted growth, distorted leaves, and yellowing foliage.
Treatment: To control aphids on Great Blue Lobelia plants, you can try spraying them off with a strong stream of water or using insecticidal soap. Ladybugs and lacewings are natural predators of aphids and can help keep their populations in check.
Slugs and Snails
Slugs and snails are common garden pests that feed on the foliage of plants, leaving behind large irregular holes in the leaves of Great Blue Lobelia. These pests are most active at night and on damp, overcast days.
Treatment: To control slugs and snails, you can handpick them off your plants in the evening or set up beer traps to attract and drown them. Applying a barrier of crushed eggshells or diatomaceous earth around your plants can also help deter these pests.
Japanese Beetles
Japanese beetles are metallic green and copper-colored beetles that feed on the foliage of a wide variety of plants, including Great Blue Lobelia. They skeletonize leaves by eating away the tissue between the veins, leading to extensive damage if left unchecked.
Treatment: To control Japanese beetles, you can handpick them off your plants early in the morning when they are less active. Neem oil or insecticidal soap can also be used as organic control options. Applying row covers over your plants during peak beetle activity periods can help protect them from infestation.
Caterpillars
Caterpillars are the larval stage of moths and butterflies, some of which feed on the foliage of Great Blue Lobelia plants. Common caterpillar pests include cabbage loopers and tobacco hornworms, which can quickly defoliate a plant if not controlled.
Treatment: Handpicking caterpillars off your plants is an effective control method for small infestations. Bacillus thuringiensis (Bt) is a biological insecticide that specifically targets caterpillars and can be used to treat larger infestations.
Spider Mites
Spider mites are tiny arachnids that feed on plant sap by piercing the leaves of plants with their mouthparts. These pests are often found on the underside of leaves and can cause stippling, webbing, and yellowing of foliage on Great Blue Lobelia plants.
Treatment: To control spider mites, you can try spraying your plants with a strong stream of water to dislodge them. Insecticidal soap or neem oil can also be used to treat spider mite infestations. Increasing humidity levels around your plants can help deter spider mites as they thrive in dry conditions.
Conclusion
While Great Blue Lobelia is a relatively resilient plant, it is still susceptible to damage from various pests. By being vigilant about monitoring your plants for signs of pest infestation and taking proactive measures to control these pests, you can ensure that your Great Blue Lobelia remains healthy and vibrant throughout the growing season. Remember to always follow the recommended guidelines for pesticide application and consider using organic control methods whenever possible to minimize harm to beneficial insects and wildlife in your garden.