Agronomic Minute: Vineyard Weed Control in Dry Conditions

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Vineyard Weed Control

Dry conditions over the past month can have an impact on vineyard weed control approaches. Most growers prefer to activate preemergent herbicides with a rain event. However, the lack of significant rainfall in recent weeks is shifting some application practices. UPL Technical Service Manager, Emily Smith said addressing weed management through drip irrigation can be effective and provide some added benefits.

“With preemergent herbicides you really want to get those down into the soil profile because that’s where the dormant seeds are that are waiting to sort of grow when the conditions are right,” said Smith. “So, if you run Satellite, or Pendimethalin, through the drip, then that kind of gets it into the soil profile and acts as your rain event. That can be great as a preemergent.”

Most vineyard weed control plans account for pests such as knotweed, morning glory, and puncturevine. Smith explained that lambsquarter was also especially problematic last year. Lambsquarter seemed to be somewhat more drought tolerant and tougher to kill with contact materials last year. “Using a preemergent to try to get ahead of that is going to be really key for this growing season. That’s kind of a tough to control weed,” said Smith.

Growers will need to stay diligent with their weed control programs. A lack of visible weeds in the vineyard does not mean there are no weed issues that will need to be addressed.  Smith noted that adding preemergent materials to the drip line can actually be a bit more advantageous than relying on a rain event to bring the product down in the soil.

“A lot of [weeds] will grow under the drip emitters because that’s where the water is going to be throughout the season, especially in a dry year,” said Smith. “So, where they’re concentrated like that under the drip, this makes it that much more effective because you’re going to water in your product right where your issues are going to be later in the season.”

Listen to the full episode below.