How does Trichoderma control root knot nematodes?

Real IPM Trichoderma is Registered in Kenya and Ethiopia for the control of root knot nematode. Its probable mode of action is the excretion of a chitinase enzyme, which destroys the egg masses of nematodes on the outside of the plant roots.
A root gall contains one large single female nematode. She extrudes eggs masses on the outside of the root and then dies. The gall will not disappear and remains as historical evidence of rkn presence. If Trichoderma is applied regularly with the irrigation water, the number of new galls should decrease.

Are biopesticides protective or curative?

Biopesticides are more effective when used in a prophylactic preventative programme, not dependent on thresholds or scouting. The colonization of the rhizosphere by beneficial microbes in advance of the attack by pathogens and pests will reduce the living space on the roots where the pathogens might attempt to colonise. Beneficial microbes will secrete substances, which can slow down the growth of the competing pathogenic microbes or kill them. This will reduce the level of disease or pest attack on the plant.

What is the difference between Systemic Acquired Resistance (SAR) and Induced Systemic Resistance (ISR)?

ISR is usually initiated as a result of beneficial microbes applied to the roots of the plant and increases the level of jasmonic acid in the plant tissues. Beneficial microbes that are applied to the canopy usually induce SAR and it tends to increase the level of salicylic acid in leaf tissue.