Trichoderma harzianum

About: Trichoderma harzianum is a research topic. Over the lifetime, 4731 publications have been published within this topic receiving 96796 citations.

The in vitro effect of certain fungicides, insecticides, and biopesticides on mycelial growth in the biocontrol fungus Trichoderma harzianum.

Abstract: The in vitro effect of certain fungicides, insecticides, and biopesticides on mycelial growth of Trichoderma harzianum was evaluated. Seven systemic fungicides, 2 contact fungicides, and 4 biopesticides were tested. A progressive increase in percent inhibition of radial growth in the fungus was observed as the concentrations of the fungicides increased. Among the systemic fungicides, hexaconazole was the most toxic, followed by propiconazole and triflumizole. Toxicity of the contact fungicides was lower than that of the systemic fungicides, among which copper oxychloride and copper hydroxide were highly compatible; no inhibition was observed at lower concentrations. In terms of the insecticides tested, quinalphos and dicofol exhibited toxicity (quinalphos more so), even at the low concentration of 10 ppm. Endosulfan, fenpropathrin, and propargite were less toxic, which indicated the compatibility of these insecticides with T. harzianum. A varying level of inhibition was observed in response to the biopesticides. Although neem-based biopesticides completely inhibited the growth of the biocontrol strain, ovis was compatible with the growth of Trichoderma harzianum. The present results will help delineate the possibility of combining T. harzianum biocontrol agents and agrochemicals for use in an integrated pest management approach.

The expression of extracellular fungal cell wall hydrolytic enzymes in different Trichoderma harzianum isolates correlates with their ability to control Pyrenochaeta lycopersici

Abstract: Four isolates of Trichoderma harzianum (ThN3, Th11, Th12 and Th16) were selected for their ability to control the in vitro development of the tomato root pathogen Pyrenochaeta lycopersici. Analysis of the mechanisms involved in biocontrol showed that the formation of non-volatile metabolites appears to be one of those involved in biocontrol of P. lycopersici by all T. harzianum isolates tested. Nevertheless, the higher secretion of chitinases, both in number of isoenzymes and activity by the Th11 strain, correlated well with its higher ability to control this agent in laboratory and greenhouse experiments as compared to the other T. harzianum isolates tested. The secretion of beta-1,3-endoglucanases and/or proteases appeared to have less significance than endochitinases in the biological control of P. lycopersici.

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.