Submitted to: Horticultural International Congress Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 6/1/2003
Publication Date: 1/15/2004
Citation: Vavrina, C., Roberts, P., Burelle, N.K. 2004. USE OF COMMERCIAL SYSTEMIC ACQUIRED RESISTANCE (SAR) INDUCERS IN THE STAND ESTABLISHMENT OF TOMATO; IMPACT ON PLANT GROWTH, DISEASE AND NEMATODE SUPPRESSION. Horticultural International Congress Proceedings. 631:231-238. Interpretive Summary: Research has shown that various aspects of transplant production and handling can greatly enhance yield. A transplant technology that has shown promise in satisfying several production criteria is the use of certain compounds or biologicals to induce systemic acquired resistance (SAR) and plant growth promoting (PGP) effects. The SAR and PGP effects elicited when organisms or compounds are introduced during transplant production often carry over into the field to further benefit the plant in pest control, general growth and yield. The objective of this study was to develop a research data base on plant growth, yield, and systemic acquired resistance effects of disease and nematode suppression elicited by the application of commercially available products on tomato transplants. Among the products tested were: biological control agents, pathogenesis-related proteins, natural products, agricultural chemistry, fertilizers, and inert ingredients. Though few significant SAR growth-enhancing effects were documented in this trial it is notable that the plant growth promoting rhizobacteria, B. subtilus, the biologically active ingredient of Pro-Mix VFT, did promote growth in tomato transplants. These products may also be of limited use in the suppression of bacterial spot development on tomato. None of the materials tested reduced nematode galling, however several improved root condition. Uninterrupted root growth and sustained health in the face of nematode infestation would certainly be advantageous for the plant. Clearly SAR products cannot substitute for agricultural chemicals designed for specific pests, but induction of resistance prior to actual infestation may prove beneficial in many respects. Continued experimentation in this area is necessary to define the SAR effect, increase production efficiency, maximize yield, and develop protocols for best management practices.
Technical Abstract: Eleven commercially available materials advertised as promoting a SAR response in plants were applied to tomato transplants in the greenhouse. The treatments consisted of biological control agents, defensive proteins, plant activators, organic compounds, modified fertilizers, inert compounds, and a control. Two weeks after treatment, the transplants were measured to document SAR induced plant growth enhancement then either inoculated with a suspension of Xanthomonas campestris pv. vesicatoria or transplanted into pots containing field soil naturally infested with root-knot nematode (Meloidogyne incognita). Few significant SAR growth-enhancing effects were documented, however three SAR materials advanced fruit maturity resulting in early ripening. Three products showed limited suppression and one product enhanced bacterial spot development on tomato. None of the materials tested reduced nematode galling, however four improved general root condition. Though further research is necessary, these results help to define the SAR contribution to a systems management approach to commercial agriculture.