Control of the fungi Lasiodiplodia theobromae, the causal agent of dieback, in cv. syrah grapevines

Abstract

Grapevine trunk diseases are among the most important limiting factors of worldwide viticulture. In this context, we aimed to verify the effect of chemical fungicides, biological agents and plant extracts on the control of Lasiodiplodia theobromae in pruning wounds and their physiological effects in cv. Syrah grapevines. Plant extracts (clove, cinnamon, garlic, rosemary and lemongrass), commercial fungicides (difeconazole, tebuconazole, mancozeb, sulfur, pyraclostrobin, fosetyl-Al, and azoxystrobin), chitosan, Trichoderma harzianum and Bacillus subtilis were used for the in vitro trials. The protection of pruning wounds in the potted vines was studied using fosetyl-Al, tebuconazole, Trichoderma harzianum, Bacillus subtilis, garlic extract and clove extract. The experiments were carried out through two vegetative cycles: 2015/2016 and 2016/2017. The length of wood discoloration, pathogen re-isolation percentage, fresh mass of the pruning material, peroxidase activity, fluorescence, chlorophyll index, phenological stages, shoot length and leaf area were evaluated. The treatments with clove, garlic extract, tebuconazole, pyraclostrobin, mancozeb, fosetyl-Al and B. subtilis reduced mycelial growth by more than 90%. In the grapevines, the use of T. harzianum decreased the re-isolation of L. theobromae, but no differences were verified for the other plant evaluations. We concluded that the use of T. harzianum would be a potential option for wound protection without altering the physiological aspects of cv. Syrah grapevines.

Combining an HA + Cu (II) Site-Targeted Copper-Based Product with a Pruning Wound Protection Program to Prevent Infection with Lasiodiplodia spp. in Grapevine

“…Research on BCAs has greatly increased over the last years, being Trichoderma species the most studied as bio-pesticides [49]. Several Trichoderma-based products are currently used as pruning wound protectants against GTDs (for review see [1] and [28]) and several studies have been conducted using these products, showing encouraging results, against Botryosphaeriaceae species [28,40,[50][51][52][53][54][55][56]. However, although several promising solutions currently exist, it seems impossible to manage Botryosphaeria dieback using only a single approach.…”

Trichoderma carraovejensis: a new species from vineyard ecosystem with biocontrol abilities against grapevine trunk disease pathogens and ecological adaptation

“…(2018) . Cinnamon also showed antifungal activity against pathogenic fungi ( Rusin et al., 2020 ). The combination of this product and Trichoderma completely inhibited its growth, so it is not advisable to spray cinnamon over vine plants if Trichoderma is present in the vineyard.…”

Assessment of Conjugate Complexes of Chitosan and Urtica dioica or Equisetum arvense Extracts for the Control of Grapevine Trunk Pathogens

“…The control of these two and other Botryosphaeriaceae taxa has been extensively studied in vine plants through the use of fungicidal substances, biocontrol agents or natural products. Rusin, et al [42], in a study on the control of Lasiodiplodia theobromae employing a combined set of BCAs, synthetic fungicides and natural products, found different protection levels depending on the product applied, but in the case of plant extracts (garlic and clove), these authors obtained average length values higher than those obtained with the assayed synthetic fungicides and BCAs. Amponsah, et al [43] evaluated the sensitivity of certain Botryosphaeriaceae taxa (N. luteum, N. australe and D. mutila) against several technicalgrade commercial fungicides in potted grapevines treated with chemicals, and reported dieback lesion lengths for N. luteum noticeably lower than the ones obtained in our study.…”