Plant activators induce defense responses in plants, which can prevent or slow pathogen infection and some of these products have been reported to enhance yield.  This project tested several activators labeled for use in NY to determine whether induction of defense response pathways could be followed in the field and whether these product could be utilized in a manner that if there is any yield improvement or efficacy against common tomato diseases.  While we did not see a yield enhancement using products that are suggested to increase yield, we did see encouraging results for disease control. We found that one class of activators (the SAR-inducing type) controlled bacterial speck of tomato without negatively affecting yield.  The ISR-inducing activator failed to provide protection from bacterial diseases.  Also, this compound produced inconsistent growth enhancement over several field seasons and it is not clear whether this type of compound (ISR-inducing) provides yield enhancement.  Based on these findings, we believe that the SAR-inducing compound could be a valuable addition to an integrated management program of bacterial disease of tomato.