What Will Kill Bugs on a Rubber Plant?

Sap-sucking Bugs

• Aphids, scales and mealybugs occasionally colonize rubber trees. All three bugs attach to the stems and the backs of leaves, where they drain sap through hollow, needle-sharp mouths. A white, powdery covering distinguishes flat, segmented mealybugs from scale insects protected beneath disc- or dome-like shells. Long-legged pear-shaped aphids may be yellow, green, orange, pink, tan or black. Damage from these pests includes yellow, wilted leaves and generalized weakening. They also produce honeydew, a transparent sticky waste that attracts black sooty mold to the plants. Nearly invisible, eight-legged sap-ingesting spider mites stipple and curl the foliage and may spin fine webs between the stems and leaves.

Ants

• Ants often flock to honeydew-coated plants to feed on the sugary waste. On outdoor plants, ants protect their honeydew supply by killing ladybugs, predatory wasps, lacewings, mites and other beneficial insects that prey on aphids, scales, mealybugs and spider mites. These beneficials, however, seldom appear indoors. Without this biological natural control, untreated populations of ants and honeydew producers on your rubber tree may soar.

Other Bugs

• A rubber plant in an overly dry environment may also attract tiny winged thrips. These bugs scrape the leaf surfaces with their rasping mouths and suck up the cellular contents, including chlorophyll. The normally smooth and leathery foliage becomes rough and streaked with silver. It may brown and fall from the plants. Some thrips species also pepper the leaves with black waste.

Killing Rubber Plant Bugs

• For a lethal bug treatment that won't harm your family or pets, spray your rubber plant with a ready-to-use insecticidal soap. Applied according to the manufacturer's specifications, insecticidal soap dehydrates soft-bodied rubber-plant bugs. If you prefer, make your own insecticidal-soap solution by mixing 5 tablespoons of liquid dish or hand soap in 1 gallon of soft water. Set the plant in a sink or shower and spray until it drips. Make sure you hit the backs of the leaves, where the bugs commonly feed. If your rubber plant is outside for the summer, spray it when the temperature is below 90 degrees Fahrenheit and rinse it with water after two or three hours to protect against possible sun damage. Insecticidal soap only kills on contact, so spray the plant once or twice more over the next week to eliminate any survivors. Once your plant is free of honeydew, the ants will move on.