Induced resistance

Induced resistance is a special type of biological disease control, where the control is exerted by the plant itself, through activation of inherent defence responses, activated by prior treatment with an inducer. Inducers are of many types, ranging from different chemicals, different microorganisms (fungi and bacteria) and constituents thereof to plant extracts (botanicals).

Research on induced resistance spans from screening of inducers effective under controlled conditions to tests in the field. A very important aspect of studies of induced resistance is examination of the mode of action of successful inducers, i.e., whether they activate defence responses in plants or whether they have any direct toxic effects on the pathogen. Therefore, studies of infection biology of the pathogen and defence responses are important in studies of induced resistance.

 

Leaf extracts of neem (Azadirachta indica) tested against Bipolaris maydis in maize. Symptoms scored 3 days after inoculation.