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The impact of the re-emergence of Black Rot
This disease was first seen in 1804 in Kentucky, North America, and arrived
in Europe in 1886, when the first incidences occurred in the South East of
France. Depending on the year, this disease can completely destroy the
grape bunches unless effective protection is applied.
To protect the bunches and the leaves, growers used to rely on the
secondary effects of different products already being used for the control
of Downy Mildew and Powdery Mildew, such as Mancozeb, Folpet, Metiram
(Downy Mildew products) and DMI, QOI, SDHI (Powdery Mildew and Botrytis
products).
Since 2018, many areas across the whole of Europe have been badly
affected, due to the withdrawal of active substances and/or the changes in
vine protection strategies.
• Mancozeb ban: 2 million hectares of Black Rot protection need to be
replaced.
• DMI ban: 580,000 hectares of Black Rot protection need to be replaced.
• Folpet restriction: Integrated Pest Management (IPM) in Italy, restriction in
Germany, prohibition in certain areas of France due to the H351 statement,
restriction on chemical active ingredients in Czech Republic.
• Lack of effective solution in organic production.
Black Rot,
alias
Guignardia bidwellii
, attacks the leaves from BBCH 11 (first
leaf unfolded) to BBCH 69 (the end of flowering) and subsequently impacts
the berries from BBCH 61 (flowering) to BBCH 79 (the majority of berries
touching), so the protection applied needs to be effective for 85% of the
spraying period.
Rain (as little as 0.3 mm) and humidity (> 90 % during six hours) both play a
big role in the development of Black Rot.
Black Rot is the most significant top of mind secondary disease for vine
growers.
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