| Abstrakt: |
The tuliptree scale, Toumeyella liriodendri (Gmelin) is a pest of yellow-poplar reproduction. By removing the sap, scale attacks on seedlings, saplings, and poletimber result in distorted, low-vigor, or dead trees. The taxonomic history of the scale, distribution, and secondary hosts is given. The scale has 1 generation per year; crawler production begins in August. Dispersal is via windblown crawlers. Mating occurs in June, and the females produce copious amounts of honeydew from June through August. Important biotic control agents include larvae of a predaceous moth Laetilia coccidivora (Comstock); a ladybird beetle, Hyperaspis proba proba (Say); and a parasitic syrphid fly, Baccha costata Say. Ants that collect honeydew suppress the biotic agents, so scale populations are large. The excretory behavior of the scale is altered when tended by honeydew-feeding ants; honeydew is excreted slowly rather than forcefully. Physical factors such as ice, snow, and temperature extremes produce scale mortality. |
