How does biochar influence plant biotic stress?

Adding biochar to soil can affect the response of plants to biotic stresses because the biochar addition changes the plants’ chemical, microbial, and physical environments. These changes elicit cascading feedback responses in the plant that can activate or alter its innate defenses. This chapter has a number of aims: (i) briefly review plant pathogens and pests, and the defenses plants have against them; (ii) summarize the impact of biochar on plants’ ability to cope with pests and diseases; (iii) critically synthesize current understanding of biochar modes of action with respect to biotic stresses; (iv) discuss techniques that may lead to improving the ability of biochar to help plants contend better with biotic stresses; and (v) identify future research needs.