Whether you’re new to this or you just need a bit of confidence to assure you’re doing things alright, there are some questions that you might be asking yourself too that need some clarification.
Let’s get them answered today!
Here are the top three questions I get from growers:
What is the best method to train my newly planted grape vines?
Focus on establishing a healthy root system. Without that healthy root system, the trunk, the cordons, and the canes that you’re going to use for your fruiting wire – none of those are going to matter.
A healthy root system is needed to support the new growth that you need to finish establishing the vine. This also supports the fruit on your first crop that you’re going to eventually get.
In year one, I prefer to take everything off except for one shoot. Leave one strong, straight, well-positioned shoot coming off above the graft or the one-year-old bud wood if it’s an ungrafted vine. Grow that one shoot and tie and train it straight as if you’re trying to form a trunk. You often will not get a trunk in year one, but it has been done.
What are these spots on my leaves?
Spots are caused by a variety of reasons, and oftentimes, they’re confused with diseases when there’s no real cause for concern. Factors that cause spots on the leaves may be abiotic or biotic.
Abiotic Factors:
- Physical damage (eg. Wind that causes your leaves or your shoots to rub up against your trellis wires)
- Herbicide drift
- Environmental factors such as oxidative stipple or spots on the upper side of older leaves that are caused by elevated atmospheric ozone levels
Biotic Factors:
These are more worrisome because they can potentially spread and they could also cause major leaf loss. Some of the most prominent fungal diseases can cause spots on leaves such as from black rot, phomopsis and downy mildew.
What to do:
Remain calm. Retrace the events that happened in your vineyard so you can reverse-engineer anything that could possibly have led to this spotting.
Think about weather conditions and patterns (rain, hot, cold, freeze, wind). Or maybe you have a historical problem in your vineyard the year prior with black rot, or downy mildew and those should be on your scouting list. Usually, spots start to show up within a week to two after a weather event like this.
Make sure to do some good record keeping in your vineyard and write everything you do in your journal, including the weather and all the necessary information for you to have a complete story.
If you’ve found that the spots are caused by abiotic factors, there may not be much you can do to respond in most cases. However, if it’s a biodic factor such as disease, then respond and make sure you’re putting on some type of preventive or curative spray.
Should I spray my vines before or after a rain event?
This can be a tough issue for growers because the intuitive and logical presumption is that rain will wash off a spray rendering it useless.
Preferably, spray before the rain because most spray products are designed to help protect your leaves and your fruit throughout that rain event. There may also be instances where you have to come back in and spray after the rain as well, especially if you know you had enough moisture to wash off that product.
There are things you can do to make the product last longer through the rain. But sometimes you’re going to need to spray both before and after the rain to prevent diseases. If you want to hear more details and examples about spots on leaves check out vineyardundergroundpodcast.com/003
