Competition in the Vineyard

While Blog #4 explored Missouri's opportunity, the reality is that every vineyard here fights constant competition. This past season reminded me of just how many ways the vineyard tests your resolve.

Disease Pressure

Grey Botrytis (July 15–August 31)

Botrytis is often romanticized as "noble rot" in Europe, but in Missouri humidity it's anything but noble. Between mid-July and late August, I battled Grey Botrytis head-on in Carol's Vineyard. I was able to avoid whole clusters turning soft and fuzzy, threatening to collapse into full-on sour rot by consistently spraying a consistent fungicidal regiment. However, as shown in the above picture I did find some grey rot on a few grapes here and there.

Prevention & Combat: I relied on open canopy management, cluster thinning, and a stepped-up spray rotation to slow its spread. The best defense came from sunlight and airflow, Missouri's muggy nights are perfect for Botrytis, so drying fruit quickly after rains is essential.

Rachis Necrosis (Throughout Season)

Toward the end of the season, after veraison, I began seeing rachis necrosis, the drying and collapse of cluster stems that choke off fruit. The first instinct was nutrient imbalance, so I started digging and sending soil samples for analysis of potassium (K), nitrogen (N), calcium (Ca), and other micronutrients. But my suspicion is that the primary driver was insect and pathogen pressure. I didn't get Spinosad into the rotation until late, which may have left the rachis vulnerable earlier in the season.

Prevention & Combat: Earlier scouting and earlier insecticide timing will be critical. Nutrient tests will confirm whether a soil correction is also needed. In the meantime, sanitation, removing dead tissue, and balancing canopy vigor will help reduce carryover risk.

Mildews & Rots

Alongside Botrytis, downy mildew flared after heavy rains, leaving its trademark yellow oil spots on leaves. Powdery mildew thrived in shaded canopies, while black rot was a lurking threat in early summer. Each of these can wipe out a crop in days if left unchecked.

Prevention & Combat: Consistent rotations of fungicides, leaf pulling for airflow, and careful shoot positioning became my standard defense. Walking the vineyard often was my greatest tool, spotting the first signs before they spiraled out of control.

Pests

Japanese Beetles

By midsummer, Japanese beetles arrived in their usual waves, skeletonizing leaves and stressing vines. Once we got the pheromone bags onsite it was amazing to see how many of those knuckleheads buried themselves into the bags.

Prevention & Combat: Hand removal, targeted sprays, and pheromone traps helped suppress populations. Long term, encouraging birds and beneficial insects provides natural balance. I have been thinking about buying one of those early 2000's Volkswagen Beetles and having it wrapped like a ladybug to park it in the vineyard for an intimidation factor to the aphids and pests that tend to try to make my vines home.

Grape Berry Moth & Insects

Grape berry moth added another layer of stress, laying eggs that led to larvae boring into fruit. This not only caused direct berry loss but opened doors for Botrytis. Late arrival of Spinosad in my spray program made an impact and I need to make sure we get this out earlier.

Prevention & Combat: Mating disruption ties and early-season insecticide programs are the path forward. Removing dropped clusters cuts off the moth's life cycle.

Climate Competition

Water (humidity and rain) and heat are Missouri's constant double-edged sword as mentioned in the previous blog. However, this is something we can crush with consistency. The same rainfall that powers growth also sets up mildew and rot. Heat spikes in July stress vines just as berries are ripening. Late frosts threaten in the spring, and hail is never out of the question. With proper rootstocks the vigor from this combination can be tamed.

Prevention & Combat: Site selection, drainage, and canopy management are my main defenses. Timing field work around weather events becomes a chess game: hedging before storms, spraying in the narrow windows between rains, and managing vigor to let sunlight through.

Conclusion

Missouri vineyards are an adventure. Grey Botrytis, rachis necrosis, phylloxera, beetles, mildew, and the weight of climate, each is competition in its own right. Yet these struggles give the wines their depth of character. When a bottle of Missouri wine makes it to the table, it carries not just the fruit of the vine, but the backbone and resilience of a season's fight.