Natural defense systems enable trees to ‘fight back’ when they’re under attack from pests or disease or facing stress from environmental conditions like drought. Even with these defense systems in place, trees will decline when conditions become too severe or persist over long periods of time. Research and field experience has shown that application of potassium phosphite can increase resistance against a variety of pathogens and improve a plant’s ability to tolerate these environmental stresses.
As a fully systemic material, potassium phosphite can be applied as a foliar spray, a soil injection for root uptake or as a bark spray. It has been gaining more and more attention in arboriculture for its ability to enhance the rate and intensity of existing tree and shrub defense mechanisms. This includes improved production of plant defense hormones, increased phytoalexin (antibody) production and enhancement of plant processes related to programmed cell death, which limits pathogen spread.
Given its unique properties, potassium phosphite is a good treatment to consider in a number of common situations.
- Management of specific soil borne diseases such as Phtyopthora root disease and Armillaria root rot
- As a direct treatment for bleeding cankers on tree trunks, including those caused by Phytophthora species and some bacterial species
- As a means of enhancing general resistance against a variety of secondary or stress-related pathogens
- To promote general plant vitality
- To enhance resistance against environmental stress factors such as drought or water-logged soils