Potential Use of Elicitors from Trichoderma in Induced Systemic Resistance for the Management of Phytophthora capsici in Red Pepper

Abstract

Eleven isolates of Trichoderma harzianum were screened for their potential to induce systemic resistance against Phytophthora capsici in red pepper plants. The effect of talc formulations of these eleven isolates on induction of glucanase activity and phenol content was studied. There was a significant increase in glucanase activity in plants treated with Th8 and Th1 (94 and 90 μg glucose released min -1 g -1 ) compared to control (77 μg). Similarly phenol content also increased in plants treated with Th4, Th7 and Th10 (48-59 μg g-1) compared to control (34 μg g -1 ). Cell wall glucan elicitors were extracted from T. harzianum isolate Th10 that had been reported earlier as an efficient biocontrol agent. Treatment with elicitor preparations also induced high glucanase activity (40 μg glucose released min-1 g-1) and increased phenol content (42 μg g -1 ) compared to control where the glucanase activity was 33 μg glucose released min -1 g -1 while phenol content was 27 μg g -1 . Similarly the elicitor treatment as seedling dip reduced P. capsici infection to 23% compared to control (93%). The potential use of ISR eliciting isolates in the biocontrol of P. capsici in red pepper is discussed.