Viticulture Association of the Santa Cruz Mountains
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vines are off and running. As
temperatures increase so do the length of the shoots. It is this period of time
between budbreak and fruit set that the greatest amount of vegetative growth
takes place. It is an important time to protect fresh green foliage from early
infections of powdery mildew. Dormant cleistothecia release active ascospores of
powdery mildew via spring rains onto the young shoots and leaves. These primary
infections can establish on new growth within 6 to 7 days after a rain. Powdery
mildew loves our climate as much as do the premium wine grapes. The optimal
temperature for spore germination is between 70 to 86 degrees F. The pleasant
spring weather that we all hope to enjoy requires our vigilance in protecting
the developing tender soft plant tissue so favored for colonization by the new
spores. Develop a plan now for a
regular spray program that can be adapted to adverse rainy conditions followed
by pleasant temperatures. Protecting the shoots now will go a long way toward
protecting the fruit after set.
Water and nitrogen are two other key factors in rate of
growth. It has been a wet winter and the water table is full. Soil conditions
are ripe for plenty of growth. If your vineyard has experienced too much growth
and you want to reduce vigor consider keeping the ground cover mowed instead of
discing it in. Maybe leave a few kicker canes on the vines and remove them after
8 -10 inches of growth on the shoots on those canes. Definitely hold off
irrigation until you see some sign of vegetative growth slowing down. Monitor
soil moisture carefully either with one of the fancy new monitoring devices
(some are somewhat reasonably priced) or just take out the trusty shovel or soil
probe and dig into the ground to see how things are drying out.
As always, pay attention to your fertilizer program. What you
did last year might not be necessary again this year. Look to your petiole tests
from past years to note any deficiencies. You may want to focus more on
micronutrient management if you have had problems with fruit set. Many vineyards
are commonly deficient in zinc and boron. Applying these with your regular
foliar program pre-bloom will contribute to a more even and successful fruit
set. This is especially true if you have noticed deficiencies in last year’s
petiole samples. If you didn’t take samples last year than think back to how
your fruit looked. If it was uneven in set or the clusters had little and big
berries you could be looking at a micronutrient deficiency.
Calcium is another product that is available in some foliar amendments
that can contribute to healthier vine tissue and fruit formation.
Finally, pay attention to canopy management right from the
start. After budbreak is complete
look at shoot density. Reduce doubles (two or three shoots emerging from the
same bud) to one healthy shoot per bud. If you have a VSP system, be sure to
start training the shoots to grow straight up right from the start.
Don’t allow them to cross in front of other shoots and allow enough
space between shoots for airflow and light penetration. Remember that each shoot
will produce 1 or 2 clusters per cane. Make sure to allow space for that fruit
Keep the weeds down and enjoy the promise of this time. Plant
extra flowers and other attractive plants to enhance the beauty of your place
and to promote biodiversity. Beneficial insects love the sweet nectar of a
variety of flowers. Having an abundance of variety contributes to the health of
the population and is easy on your eyes.
Finally, be on the lookout for early mealy bug infections.
Get some traps from your local Agricultural Commissioner and hang them in your
vineyard. Start a monitoring program now to see if you are at risk.
Your local viticulture organization is hard at work expanding
opportunities for growers in our appellation. We are working with the Santa Cruz
Winegrowers Association in the planning and presentation of Pinot Paradise and
the April Trade Tasting. VASCM will have a booth at both events and will be
hosting grower-winemaker “vignettes” that offer the public an informal and
intimate insight into the relationship between grower and winemaker through the
season. Development of a logo, ongoing presentations, and emphasis on the unique
attributes and publicity for what makes the Santa Cruz Mountain appellation
special continue to be a major focus for our organization.
Thank you for your support and be well and attentive as we
start off 2005.
La vaya bien and good luck to all!
(VASCM newsletter, March 2005)
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