CHARACTERIZATION OF HYBRID POPLAR CLONES FOR RESISTANCE TO THE FORESTTENT CATERPILLAR

Forest tent caterpillar, Malacosoma disstria Hbn., behavioral and deve lopmental interactions with 15 hybrid Populus spp. clones were studied in laboratory and glasshouse trials. Significant differences in larva l preference and performance among the clones were found. Larval devel opment time ranged from 30 to 52 days. Second-instar preference and la rval development were significantly correlated, but 4th-instar prefere nce and larval development were not. Second- and fourth-instar prefere nces were not correlated. Clonal productivity and tolerance of defolia tion varied significantly, but were not correlated. The relationships between productivity, defoliation tolerance, and insect resistance wer e examined in regard to plant defense theory, host plant resistance, c lonal selections for tree improvement, and assay utility.