PEST & DISEASE
Late season Botrytis There is nothing worse than seeing your beautiful bunches rotting in front of your eyes. The presence of La Niña – with rain events scattered through the harvest period – could affect grape growers,
What can you do? If there was a severe Botrytis infection in your vineyard this season next season is high. Varieties with a
your chemical representative. v
high susceptibility to berry splitting will need extra attention.
While it might be only one of many
-R emove mummified bunches
bunch rots, with another La Niña
-R educe spore load by removing vine
your bunches from Botrytis bunch rot? The answer, to a certain degree, lies in the way Botrytis infects.
debris and remnants -A pply protective fungicide at 80
rains, always paying attention to
have survived in bunch remnants
optimum coverage
Spore germination can occur at any time if conditions are favourable (temperatures around 18-21º Celsius) and if vines stay wet from rain, fog,
-A pply a protective spray at prebunch closure, as this is the last opportunity to get good spray coverage within the bunch, where latent infection often emerges -M inimise berry wounding (wounds
dew or mist. Once tissue is infected,
are entry points) by controlling
the infection can lie inactive – latent
light brown apple moth (LBAM) and
– until conditions are ideal for spread.
powdery mildew
Fortunately, not all latent infection leads to rotten berries, as hot, dry weather through summer and autumn can prevent development. High relative humidity in the bunch zone and excessive soil moisture can activate
https://www.wineaustralia.com/ getmedia/3e2d4ecc-3d70-41db-b2b00b897a513fb8/CORD_Factsheets_ BotrytisManagement
- I f the flowering period is prolonged, protect with a fungicide before it
wind, or carried by insect vectors.
https://www.wineaustralia.com/ getmedia/b78baaea-d1de-469f-a8aa1aec30d4d756/201307-Botrytis-QA?ext=.pdf
flowery parts is critical
for infection to occur. Spores that
can be splashed around by rain,
Information for this article has been sourced and adapted from:
per cent capfall – good coverage of
Flowering is the first opportunity
(floral parts and leaf material)
- There are new chemical options available for Botrytis control – talk to
Steps to take:
year, you might ask how can you guard
Botrytis late season.
and/or wet spring, the risk of Botrytis
with late Botrytis rearing its ugly head.
season currently predicted for next
considered if you need to treat
-L imit humidity in the fruiting zone; manage canopies to allow air flow -B unch thinning, stretching and bunch removal helps prevent compact and crowded bunches
Botrytis.
-P revent excessive soil moisture
Botrytis spores are almost always
- I t is difficult to get good spray
present in vineyards. Late season
coverage inside mature bunches,
infection often occurs when rain
where Botrytis often emerges and
splits berries and spores enter the
spreads. Once botrytis appears in a
wound. Any other berry wounds – from
bunch, spray application of sanitisers
insects, mildew infection, frost, hail
only inhibits the fungus
or sunburn – can be entry points too.
on the surface at best, and even
Preventing berry split reduces the risk
surface mould is killed, the infection
of Botrytis.
remains. MRLs must also be
VINE MAGAZINE 31
