Endophytes of Invasive Weeds:Pertinence to Classical Biological Control in India

Suppression of the water weed Salvinia molesta in India and control of the woody-perennial Cryptostegia grandiflora in Australia are two of the finest successes achieved through classical biological control (CBC). There is no guarantee, nevertheless, that CBC should always be successful in every situation. Though the enemy release hypothesis explains why invasive alien species thrive in exotic locations, there has never been a convincing explanation on the poor performance of some introduced natural enemies, in spite of the rigorous screening for their potential. Interestingly, Evans' endophyte-enemy release hypothesis provides enough clarification by implicating the absence of protective coevolved endophytes in weed populations in exotic locations. This review gives an introduction to endophytes and analyses the pertinence of the newly proposed hypothesis to CBC of weeds in India with examples.