Plant resistance to herbivores can be induced by application of elicitors such as jasmonic acid, which is a signal molecule that increases naturally in plants that have been damaged. The use of elicitors to induce resistance of crop plants against herbivores has been successful in small scale experiments but has not been developed in commercial agriculture. We tested jasmonic acid sprays as elicitors of resistance against leafminers and other pests on commercial celery fields in the central coast region of California. In two of three trials, significantly fewer leafminer adults emerged from the plants sprayed with jasmonic acid than the plants that were left untreated. In these two trials, aphid control was erratic, and thrips were not significantly reduced on the treated plants although thrips were not common during the trials. Leafminer parasitoid population densities tracked the number of available leafminer hosts regardless of treatment. The only effect found in the third trial was that conventionally grown celery had more leafminer oviposition stings than either the plants treated with jasmonic acid or untreated control plants. Treatment of plants with jasmonic acid seems to hold promise as an alternative pest management tool.