Fig. 88. Plume moths. Geranium plume moth, Platyptilia pica Walsingham; Snapdragon plume
moth, Stenoptilodes antirrhina (Lange), Pterophoridae, LEPIDOPTERA
A, Geranium plume moth.
B, Snapdragon plume moth.
C, Plume moth caterpillar.
Damage - Plume moth larvae mine the leaves and feed externally on leaves, buds, and flower parts.
Life History - There are more than 40 species of plume moths of the genus Platyptilia occurring in the United States. Two of the economically important members of this genus are the geranium plume moth and the snapdragon plume moth. Eggs are deposited singly any place on the plants, but are usually laid on newly forming flowers or on the underside of leaves of terminal young growth. Hatching occurs in 2 to 3 weeks. Young larvae mine in leaves and later burrow into the stem, petioles, flowers, or seed pods. It takes 3 to 5 weeks for the larvae to develop through four instars. The caterpillars emerge to form pupae that hang upside down on the plant. The adults are weak fliers and usually remain on or near the host plant. The moths are most active during the early evening. If hibernation is necessary, it is the adult stage that overwinters; however, the plume moths are not well adapted for hibernation or aestivation.
Geranium cuttings should be inspected upon arrival for plume moth caterpillars. A pyrethroid dip with a labeled pesticide should give adequate control of plume Moth caterpillars without damaging the cuttings or affecting rooting percentage. For specific rates and chemical control recommendations, see the current Cooperative Extension publications on ornamental plant pest management.