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 if there is any yield improvement or efficacy against common tomato diseases.  While we did not see a yield enhancement in 2006 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 any growth enhancement or protection from bacterial diseases.