Hibiscus syriacus Pests

Root Knot Nematodes (Meloidogyne spp.): "Knots or galls form on roots causing the plant to be inefficient in absorbing water and nutrients. Leaves are small and the plants fail to make normal growth. Use caution when planting to be sure that planting stock is not infested. If yard soil is contaminated, plant shrub in a large container of sterilized soil. This is probably the most serious problem experienced by althea." TAMU

Aphids "may cover the leaves with sticky honeydew. Use sprays of  Sevin, rotenone, acephate or malathion.   The insects can also be dislodged with high pressure water sprays from the garden hose." MSU

Photo of Melon aphids and mummy, courtesy of University of California, Davis.

Japanese Beetles  (Popillia japonica ) "are particularly fond of the flowers. Use sprays of malathion, rotenone, Sevin or methoxychlor to control the adult beetles. The grubs in the lawn can be controlled with diazinon or milky spore disease." MSU

Photo courtesy of Iowa State University.