Butterfly bush (Buddleja) blooms with flower clusters in shades of yellow, orange, red or purple and adapts to areas of full to partial sun. The evergreen to deciduous shrubs are often grown as small trees and are highly attractive to butterflies. A pest infestation causes shrub foliage to curl.
Butterfly bush is often infested with foliage-feeding caterpillars, the larvae of butterflies and moths. The larvae have three pairs of legs right behind their heads. They have leglike structures on other areas of the abdomen.
Foliage-feeding caterpillars have different eating habits, but all feed on the leaves. The majority of caterpillars first roll the foliage with their silk and then feed within these small shelters or cavities. Certain other caterpillars weave tentlike nests and then feed under them. Caterpillar feeding severely damages leaves and causes defoliation and branch dieback. Heavy populations can kill plants.
Prune and remove all affected plant areas. Avoid damage to plant roots and trunk. Manually remove caterpillars in cases of light population. Control newly hatched larvae with applications of Bacillus thuringiensis.