Abstract:
The first through fifth instars of the gypsy moth were tested for development to adults on
326 species of dicotyledonous plants in laboratory feeding trials. Among accepted plants,
differences in suitability were documented by measuring female pupal weights. The majority of
accepted plants belong to the subclasses Dilleniidae, Hamamelidae, and Rosidae. Species of oak,
maple, alder, madrone, eucalyptus, poplar, and sumac were highly suitable. Plants belonging to
the Asteridae, Caryophyllidae, and Magnoliidae were mostly rejected.
Foliage type, new or old, and instar influenced host plant suitability. Larvae of various
instars were able to pupate after feeding on foliage of 147 plant species. Of these, 101 were
accepted by first instars. Larvae from the first through fifth instar failed to molt on foliage of
151 species. Minor feeding occurred on 67 of these species. In general, larvae accepted new
foliage on evergreen species more readily than old foliage.
The results of these trials were combined with results from three previous studies to provide
data on feeding responses of gypsy moth larvae on a total of 658 species, 286 genera, and 106
families of dicots. Allelochemic compositions of these plants were tabulated from available
literature and compared with acceptance or rejection by gypsy moth. Plants accepted by gypsy
moth generally contain tanning, but lack alkaloids, iridoid monoterpenes, sesquiterpenoids,
diterpenoids, and glucosinolates.
