Evaluating the effect of Trichoderma atroviride (i-1237) on grapevine phomopsis cane and leaf spot: a promising and reproducible trial

Abstract

A field trial with artificial infection was designed and performed to verify the potential effect of the application, as a pruning wound protectant for grapevine trunk diseases immediately after pruning, of a commercial product containing the biological control agent Trichoderma atroviride (I-1237), on later symptom expression of Phomopsis cane and leaf spot (PCLS) caused by Diaporthe spp.. The trial comprised four modalities: “Witness”, that remained in natural conditions without artificial infection and was sprayed with distilled water during the treatments; “Infected Witness”, with artificial infection and was sprayed with distilled water during the treatments.; “Reference Product”, with artificial infection and reference fungicide application at bud burst (BBCH 09), and “Test Product” in which the T. atroviride commercial formulation was applied as per the label, during dormancy (BBCH 00) immediately after pruning, and subject to artificial infection. The trial consisted of six replicates per modality with three plants per replicate. Incidence and severity of PCLS were assessed on the first four internodes in all the canes of all trial plants during development stages “fruit set” to “berries groat sized” (BBCH 71 to 73). The effectiveness of the artificial inoculation stands out; all the modalities showed lower incidence and severity than those of the “infected witness”, and the reduction in incidence, compared to the “infected witness”, was statistically significant for all modalities. Due to its short duration, the test did not allow the initial premise to be validated, but it validated the methodology used and its reproducibility. The suggestion that the pruning application of the T. atroviride formulation influences the subsequent manifestation of PCLS will need further testing in the following years to gauge these preliminary results.