Grape growing has no off-season, even during harvest time. In order to set your grapes up for success next year, growers and PCAs must look at what’s happening in their vineyards right now. Follow these simple do’s and don’ts from UPL to ensure a strong finish this season and a strong start to the next.
- Do take notes recapping the season for reference next year
Harvest is a good time for growers to reflect on the season’s disease management program and evaluate the effectiveness of it. Wise grape growers will note when their vineyard experienced disease, the level of severity and what products were applied. Taking notes during this process will help plan for next year’s disease management program.
- Do switch up modes of action
The mode of action (MOA) you are using can be the difference between a healthy vineyard and a Botrytis outbreak. Alternating modes of action helps prevent pathogen populations from developing resistance to classes of fungicides. It is important to think about the classes of fungicides available when building your resistance management plan for the season. These classes have different modes of action and will each affect the fungus differently. UPL recommends a diseases management program that rotates fungicides with different modes of action for the most effective method of resistance.
- Don’t stop scouting
It is often forgotten that Botrytis is a threat during all seasons. Grape growers should continue walking through their vineyards scouting for any sign of disease because there’s a chance infection may still be actively occurring. Late-season Botrytis infections are most severe when relative humidity exceeds 92 percent, free moisture is present on the fruit surface and temperatures are in the 58 to 82 °F range, according to UC IPM. Ripe berries that have experienced damage from insects, birds, hail or machinery are even more susceptible to disease, as the juice in the berry can provide the necessary water and nutrients for fungal growth. This makes September a critical month for scouting.
- Don’t wait to treat Botrytis
It's no secret how devastating Botrytis bunch rot can be to grape yields, which is why it’s important to stop Botrytis in its tracks to avoid overwintering. Botrytis cinerea, the causal agent of bunch rot, overwinters as sclerotia, which are hard, resistant structures sometimes referred to as "berry mummies." Following rain or irrigation, sclerotia germinate and produce spores that travel via air currents or rain showers. Grape growers use fungicides like PH-D® and ELEVATE® to protect current fruit and minimize the potential future effects of overwintering Botrytis bunch rot and give grapevines a solid foundation leading into the next growing season.
ELEVATE Fungicide (FRAC Group 17) provides locally systemic activity and is excellent at controlling Botrytis bunch rot and powdery mildew. ELEVATE can provide post-infection activity when applied early in the disease life cycle and has been shown to enhance the efficacy of other fungicides when used in a powdery mildew spray program. With a zero-day pre-harvest interval, you can use ELEVATE up to the day of harvest.
PH-D Fungicide (FRAC Group 19) is a broad-spectrum fungicide that offers a high degree of Botrytis and powdery mildew control in grapes. Its benefits of a zero-day pre-harvest interval and 4-hour REI make it an excellent option for disease management sprays close to harvest. PH-D is the only product in FRAC Group 19, making it an important resistance management tool.
No matter the time of year, you can count on UPL for a complete line of grape protection and a staff dedicated to keeping your vineyard going strong. To learn more about the UPL portfolio of crop protection products, contact your local UPL sales representative or visit www.upl-ltd.com/us.
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