Biological Control of Potato Late Blight Using Isolates of Trichoderma

Potato late blight, caused by Phytophthora infestans is a most destructive plant pathogen and can lead to serious economic losses in potato. Some strains of the Trichoderma genus can act as potential biocontrol agents and are able to control many plant disease in crops. The present study was carried out to screen effective Trichoderma isolates against P. infestans and to study the potential modes of action involved. In vitro bioassays between P. infestans and Trichoderma isolates demonstrated that the P. infestans colony was significantly inhibited and overgrown by Trichoderma isolates . Antifungal metabolites produced by the isolate HNA14 significantly prevented the linear growth of the P. infestans colony. Mycoparasitism appeared to contribute to the aggressive nature of the Trichoderma isolate HNA14 against P. infestans when observed under scanning electron microscope (SEM). In planta bioassay , the isolate HNA14 significantly reduced the disease index, increased the plant stem height, and foliar fresh and dry weight. Under field conditions, the Trichoderma isolate HNA14 was the most efficient against the pathogen out of all Trichoderma strains, and significantly reduced the disease severity compared to the control. Collectively, the strategic approach described in this paper demonstrates an effective way of screening a biocontrol agent for control of potato pathogens.