Integrated Control of Grape Black Rot: Influence of Host Phenology, Inoculum Availability, Sanitation, and Spray Timing

Abstract

The epidemiology and control of black rot (Guignardia bidwellii) was studied from 1995 to 1999 in vineyards in Dresden and Naples, NY, where disease pressure was moderate and extreme, respectively. The efficacy of serial applications of myclobutanil, provided at 2-week intervals and varied with respect to their number and time of initiation, was examined within the context of host phenology, inoculum availability, and sanitation. At Dresden, sprays applied over 4 weeks through the immediate prebloom stage provided only 13 to 91% control of diseased clusters, despite the release of 95% of the season's ascosporic inoculum during the period of fungicidal protection. However, applications immediately prior to bloom plus 2 and 4 weeks later, which afforded protection while fruit are highly susceptible to infection, provided virtually complete control. At Naples, where mummified berries were retained in the canopy after mechanical pruning, this same regime provided only approximately 80% disease control, but applying a fourth spray 2 weeks prebloom generally improved control. Hand-pruning mummies to the ground in selected plots significantly (P </= 0.05) improved control in some spray regimes. Although this sanitation practice did not affect inoculum dynamics through bloom, very few spores were recovered thereafter from mummies collected from the ground, whereas abundant ascospores and conidia were recovered from mummies in the trellis for an additional 6 to 8 weeks.

Effect of cultural practices on the development of arabica coffee berry disease, caused by Colletotrichum kahawae

“…(anamorph of Botryosphaeria dothidea) (Mila et al 2005). Likewise, pruning during the vegetative growth period has led to the effective control of black rot of grape caused by Guignardia bidwellii (Hoffman et al 2004). In the final year of the present experiment (2005), the CBD level was the same for both types of management method, with 53% of infected berries on average.…”

“…However, the infection levels on the coffee trees varied from year to year. It was non-significant in 2003 and quite high in 2002, 2004. In 2004-2005, the average disease level on coffee trees exposed to sunlight was about 50% greater than that on the coffee trees under shade (Table 4).…”

“…However, on tree crops, pruning dead or unproductive branches and removing mummified fruits are very widespread practices. They have helped to limit the levels of various diseases such as fire blight caused by Erwinia amylovora on pear (Shtienberg et al 2003), grapevine black rot caused by Guignardia bidwellii (Hoffman et al 2004), apple scab due to Venturia inaequalis (Holb 2005), and pistachio panicle and shoot blight caused by Fusicoccum spp. (Mila et al 2005).…”

Optimizing Fungicide Applications for Plant Disease Management: Case Studies on Strawberry and Grape

“…Other groups inhibiting the sterol biosynthesis (SBI/DMI) do not have direct effect on spore germination, but impact more directly on mycelial growth. Hoffman et al (2004) found that a DMI, myclobutanil, provides a better post-infection activity against black rot of grape, compared with azoxystrobin, which provided a slight evidence of a post-infection activity.…”

Vineyard Practice

“…In climates where the incidence of black rot is frequent, and especially where mechanical pruning is practiced, inspection and destruction of infected cane wood should be practiced. For a discussion of integrated control measure see Hoffman et al (2004).…”