Activity of biostimulants towards Phytophthora infestans on tomato

Several biostimulants were tested in greenhouse and laboratory for efficacy on late blight caused by Phytophthora infestans. The greenhouse trials were carried out on tomato plants to assess the effectiveness of Kendal and Pom-PK and to test the activity of their components. The laboratory assays were carried out to verify the probable direct activity on P. infestans of the biostimulants effective in vivo. In greenhouse Kendal and Pom-PK confirmed their good activity against tomato late blight whereas most components applied separately were not effective. Only oligosaccarides and glutathione whether singly applied or in mixture showed any efficacy towards P. infestans. The laboratory tests demonstrated a fungistatic activity of Kendal, Pom-PK and oligosaccarides on P. infestans.