Vol 117 (2004): Proceedings of the Florida State Horticultural Society
Krome Memorial Institute (Tropicals)

A method to screen weed-suppressing allelochemicals in Florida biomass

James J. Ferguson
University of Florida
Published December 1, 2004
  • allelopathy,
  • weed control,
  • sustainable production systems


Wood chip mulches derived from woody species grown in Florida are sometimes used for weed suppression in perennial fruit crops, especially in sustainable and organic production systems. A method for testing allelopathic qualities of these materials was developed, including wood chip incubation and filtering followed by bioassays of lettuce seed germination and growth. Eluates of wood chips from red maple (Acer rubrum cv. 'Rubrum' L.), swamp chestnut oak (Quercus michauxii Nutt.), red cedar [Juniperus silicicola (Small) E. Murray] and sweet bay (Magnolia grandiflora L.) highly inhibited germinating lettuce seeds, as assessed by germination percentage, radicle and hypocotyl growth. The effects of eluates from these four species were more than or equal to that found for eluates from wood chips of black walnut (Juglans nigra L.) a species with a high level of allelopathic activity.