Combined application of Ascophyllum nodosum extract and chitosan synergistically activates host-defense of peas against powdery mildew.

Background: Powdery mildew (PM) is an important disease of pea that reduce yield. Ascophyllum nodosum extract (ANE) and chitosan (CHT) are biostimulants used to improve plant health. Efficacy of ANE and CHT was assessed individually and in combination against pea powdery mildew.