Spider mites feed on the underside of leaves by sucking plant sap. Damage appears as tiny yellow speckles on the upper leaf surface. Severe mite damage can cause leaf drop. Mites are favored by dry warm conditions. The common flower thrip and western flower thrip are the two most common thrips infesting garden mums.
Thrips feed on young leaves and flowers using rasping-sucking mouthparts.
Feeding on leaves causes a silvery-appearance while damage to flowers causes deformed flower buds, bud abortion, or streaking of petals. Caterpillars A number of caterpillars are pests on garden mums including beet armyworm, cabbage looper, fall armyworm, corn earworm, and European corn borer. Caterpillars can feed on almost all of the aboveground portions of the plant including leaves, stems, and flowers. Adult female moths lay eggs on plant parts which emerge as larvae to begin feeding. Adults generally migrate to garden mums when they are placed outdoors.