Broccoli and turnip plants display contrasting responses to belowground induction by Delia radicum infestation and phytohormone applications

► Glucosinolate levels were higher in both JA-treated and Delia radicum infested roots. ► D. radicum infestation reduced sugar content in infested roots. ► On broccoli, JA treatment and previous infestation reduced D. radicum performance. ► On turnip, the same treatments enhanced D. radicum performance.