In vitro screening for antagonistic potential of three Trichoderma spp. against Phytophthora spp. of Solanum lasiocarpum Dunal

Abstract

Solanum lasiocarpum Dunal (S. lasiocarpum) is an indigenous plant in Sarawak. The fruit, with its distinct sour taste is usually served as a vegetable and it is a favourite among the locals. However, the plant is susceptible to Phytophthora spp. infection, causing collar and root rot. The initial disease symptoms are wilting and yellowing of leaves which later turn necrotic. Dark brown lesions occur at the collar region, roots as well as on the stem. The control of Phytophthora diseases is usually based on fungicides. However, excessive use of chemicals poses risks to the environment and the possibility of developing resistant strains of the pathogen (Bruin and Edgington, 1980). Thus, there is a need to find an alternative method of controlling the disease, such as the use of biocontrol agents. Trichoderma species are potential biocontrol agents as they are effective in controlling diseases of plants (Kubicek et al., 2001). Major mechanisms involved in the biocontrol activity of Trichoderma spp. are mycoparasitism, antibiosis, competition, enzymatic activity and induced plant defence (Howell, 2003). Species of Trichoderma such as Trichoderma harzianum, Trichoderma asperellurn (T. asperellum) and Trichoderma virens (T. virens) posses biological control potential and the ability to increase plant growth and induce plant resistance. They have been used in crops including tomato, chilli, and eggplant to control various fungal diseases (Benitez et al., 2004). The present study was conducted to screen the antagonistic potential of three indigenous Trichoderma spp. against Phytophthora spp. of S. lasiocarpum under laboratory conditions.