TABLE CONTENTS

SESSION TWENTY-SEVEN – NEMATODE MANAGEMENT IN
PROTECTED CULTIVATIONS SYSTEMS IN TEMPERATE
AGRICULTURE
CONVENORS: BRENT SIPES & ANTONIO BELLO
Plant Growth-Promoting Rhizobacteria (PGPR) in Transplant Mixes:
Benefits for Nematode Control
Kokalis-Burelle, N.
USDA, ARS, U. S. Horticultural Research Laboratory, Fort Pierce, FL 34945
Many high-value crops including vegetables, melons, and strawberries are propagated from
transplants. In the U.S., plug transplants are typically used for vegetables and melons, while
strawberries are predominantly planted from bare-root material. However, use of strawberry
plug transplants has the potential to eliminate the need for fumigation of soil in strawberry
nurseries, where it has been difficult to identify alternatives to methyl bromide that do not
negatively impact runner plant production. Plug transplants also allow for the introduction of
biological agents such as plant growth-promoting rhizobacteria (PGPR) into the planting
medium. PGPR induce systemic resistance and/or increase tolerance to pathogens in the host
plant, resulting in increased plant growth and yield. In experimental field trials conducted in
Florida, two Gram-positive PGPR isolates (Bacillus subtilis strain GBO3 and B.
amyloliquifaciens strain IN937a) in a formulation containing chitin, reduced galling caused
by Meloidogyne incognita and improved root condition of pepper (Capsicum annuum) and
muskmelon (Cucumis melo) when added to transplant medium at seeding. In subsequent field
trials on pepper, the population dynamics of the same PGPR strains were monitored
throughout the growing season and it was determined that both PGPR strains established
stable populations in the rhizosphere that persisted through harvest. Additional aqueous
applications of PGPR during crop production did not increase the populations of applied
strains compared to treatments only receiving bacteria in the potting medium. However, infield
applications did increase plant growth compared to the untreated control. Additional
advantages of PGPR-amended plug transplants include improved stand establishment and
vigor, and earlier flowering and fruit set. It has also been demonstrated that under stress,
PGPR amended plug transplants produce higher yields.
5 th International Congress of Nematology, 2008 99