Colonisation of grapevine wood by Trichoderma harzianum and Eutypa lata

Background and Aims: Trichoderma species have potential in biocontrol of eutypa dieback; however, little is known about their ability to colonise grapevine wood. The colonisation of vines by Trichoderma harzianum and its effects on colonisation by Eutypa lata were studied. Methods and Results: T. harzianum colonised canes over a total distance (above and below the inoculation point) of 10 cm or more in 12 weeks after inoculation. Application of T. harzianum to canes prior to E. lata, either at the same inoculation point or at a different point, reduced recovery of the pathogen. In the field, T. harzianum grew 3 cm from the inoculation point in 4 months in all seven of the mature vines treated. The fungus persisted for 20 months in four of the seven vines at 6 cm from the inoculation point and reached the crown of one vine. Prior inoculation of mature vines with Trichodowels, containing T. harzianum, reduced recovery of E. lata 14 months after inoculation. Conclusions: T. harzianum colonised wood of Chardonnay, Shiraz and Nyora nd reduced colonisation by E. lata. T. harzianum persisted in wood of mature vines of Nyora for up to 20 months. Significance of the Study: The results support the potential of T. harzianum in the biocontrol of eutypa dieback.