Eradication of black rot (Guignardia bidwellii) from grapevines by drastic pruning

Abstract

A drastic pruning strategy was developed to eradicate the fungal disease black rot (Guignardia bidwellii), which is exotic in Australia, from grapevines, while minimizing the economic cost of returning an affected vineyard to its previous quality and production levels. The protocol involved cutting off vines at the top of the trunk, removing debris from the ground beneath and between vines, mulching the vineyard floor, removing low watershoots during vine regrowth and applying a targeted fungicide programme. The protocol was initially evaluated and consequently modified in Australia using an endemic grapevine disease, black spot or anthracnose (Elsinoe ampelina), as an analogous model system. Then, it was validated in a black-rot-infested vineyard in New York, USA. Following two seasons of disease-conducive weather conditions, no black rot was detected on treated vines, whereas leaf and fruit infections developed on the untreated control vines. These results confirmed the efficacy of the protocol for eradicating black rot from vineyards while allowing vines to return quickly to previous yield and quality levels without replanting. The protocol may have applicability to disease eradication protocols for other perennial crops as well. Evidence is also presented on the efficacy and potential pitfalls of burning infected grapevine material to eradicate E. ampelina.

Effect of burning and high temperature on survival of Xanthomonas translucens pv. pistaciae in infected pistachio branches and twigs

“…The majority of the wood pieces that yielded viable pathogen from these two locations were buried below the pit floor, where the temperature remained below 40°C, indicating that any pathogen in debris that penetrates into the soil might not be eradicated by burning, particularly if the pieces of wood are large and heat penetration is poor. Sosnowski et al. (2012) also reported that the fungus Elsinoe ampelina was eradicated from grapevine canes by burning, providing that infected canes did not penetrate the soil below the pit floor.…”

“…pathogen in debris that penetrates into the soil might not be eradicated by burning, particularly if the pieces of wood are large and heat penetration is poor. Sosnowski et al (2012) also reported that the fungus Elsinoe ampelina was eradicated from grapevine canes by burning, providing that infected canes did not penetrate the soil below the pit floor. Viable cells of the pathogen were also isolated from non-burned wood suspended above the pit floor; however, had these materials not been attached to poles, they are likely to have fallen into the flames and been incinerated.…”

“…One mesh bag containing infected wood in a Petri dish was attached to each of two poles at 20 cm and two poles at 50 cm above the pit floor. The pit was then filled with 32-day-old dried grapevine canes as fuel (Sosnowski et al, 2012). Another mesh bag containing infected wood was kept in the laboratory as a control.…”

Epidemiology, identification and disease management of grape black rot and potentially useful metabolites of black rot pathogens for industrial applications – a review

“…(2013 a ) hypothesized that the sudden spread in areas where it was previously almost unknown might be related to changes in fungicide application intervals, the types of fungicides used or an increasing number of abandoned vineyards. So far, black rot has not yet been observed in the major viticultural regions of Australia (Sosnowski et al ., ). However, P. ampelicida is ranked among the high priority threats to the Australian wine industry (Anonymous, ).…”

Accurate prediction of black rot epidemics in vineyards using a weather-driven disease model

“…Berries are susceptible from mid‐bloom and thereafter . Early symptoms on berries are circular white spots surrounded by a reddish‐brown ring; these spots rapidly enlarge until the entire berry rots and is transformed into a shrivelled, hard, blue‐black mummy covered with pycnidia and perithecia …”