Occurrence of juvabione-type or epijuvabione-type insect juvenile hormone analogues in three Czechoslovakian firs
a Fisheries and Environment Canada, Forestry Directorate Western Forest Products Laboratory, Vancouver, British Columbia, V6T 1 X2, Canada, b Forest Research Institute Zvolen, Experiment Station Banskti Stiavnica, Czechoslovakia, C Institute of Entomology, Czechoslovak Academy of Sciences, 16609 Praglle 6, Czechoslovakia, and d Prairie Regional Laboratory, National Research Council, Saskatoon, Saskatchewan , S7 N 0 W9, Callada