Testing Trichoderma species as biological agents for control of Dothistroma septosporum in Pinus radiata

Abstract

Biological control of pathogens can be an important tool for long-term management of diseases. Species in the fungal genus Trichoderma have been used for a broad range of agricultural functions including biological control. Here we tested if isolates and mixes of Trichoderma spp. could be effective in reducing symptoms of dothistroma needle blight, caused by the foliar pathogen Dothistroma septosporum, on Pinus radiata. Pot trials with natural and artificial D. septosporum infection and field trials were undertaken. The majority of Trichoderma treatments were not significantly different from the control. However, in one experiment, the Trichoderma treatments significantly reduced disease symptoms in one seedlot but not in the other seedlot tested. Conversely, in the field trial, one Trichoderma treatment significantly increased symptoms in comparison to the control. PCR analysis indicated that Trichoderma can persist over time, 16 months after inoculation, in the soil P. radiata seedlings were grown in, however, further investigation is required. Overall, the results from our trials showed that the Trichoderma isolates and mixes tested were unable to control dothistroma needle blight in P. radiata and are not suitable as biological control agents.