Unexpected problems can arise in the vineyard at any time of the season. Today I answer questions from winegrape growers across the country (and the world) on 7 very different topics. Check out these questions and answers to help grow your vineyard.
1. What are the visual signs of Phomopsis, and how do you treat it?
Phomopsis is a fungal disease that presents itself as black streakings on the base of the canes. It affects the petioles and leaves, and sometimes, the fruit and wood tissues (trunks and cordons). You can also find some very small spots on the lower leaves (with a yellow halo of discoloration on the outer perimeter) that can oftentimes turn necrotic.
For chronic Phomopsis year after year, try using dormant spray products. Carefully read the label and before you treat anything, and make sure you’re following your local laws and regulations. Some growers apply dormant applications before budburst using lime sulfur or calcium polysulfide. Get those sprays on before the rain splashes the spores in the spring and spreads it from old wood onto new young growing green tissues.
2. Is it too early to decide at the end of the first growing season which plants should be replaced?
Find a way to assess the vigor of your vines. If there’s enough growth (12 cm to 15 cm) on that vine, at least from the first year, you can trim the vine back to about 2 buds and let those roots catch up. But if it’s just dead on the top, and the only live tissue is right above the crown, pull it out and replant if the site is not the cause of the decline (poor soil, etc.).
Replace a damaged or failing vine earlier on, rather than waiting for three or four years hoping to get a trunk. A trunk should ideally be in place by the end of year two or three at most. If it takes four years to get a trunk, then that vine is probably not going to be very productive later down the road.
3. How can I prevent damage from grape root borer?
Pheromone disruption during active mating time of adult grape root borer seems to be the most effective control method to date. Place pheromone ties on your trellis wires at the time when you have the most flight and activity. Pheromone traps can be used to trap male moths to best determine that timing. The idea is to disrupt the mating by putting a lot of female pheromones into the vineyard so that when the males are looking for a female mate, they’re confused by all of the pheromones.
4. How do I move my Brianna vines that have a lot of gaps and missing spots from their vertical shoot position (VSP) training system to a high-wire system?
First it is important to decide if you can “fix” the gaps in your cordons or if you really should cut out the cordons completely and renew them. If you have a few spur positions missing on your cordon or they’ve died back, extend one of your good healthy spur positions into a split position so you could use a spur to creep into that area where you have the gap. If you’re choosing to extend the trunk up to a high wire and want to extend on a spur position, make sure you don’t have any big bad cuts from the past, which cause some problems or a bottleneck effect on that trunk.
It takes about three years to extend your trunk up to the top wire and develop new cordons from shoots that grow out of that trunk. You can keep the vines in production on that VSP cordon while doing this, but this makes for a very crowded canopy in your VSP as you’re trying to train trunks while also keeping the vines in production. Hence, make sure you do your proper shoot thinning to declutter, so you don’t have issues with your spray program.
5. What types of weed whackers, attachments, or anything can be used in the weedy problem areas of the vineyard?
Don’t let the weed whacker near your vines because they can do some irreparable damage to the trunks. If you have to use it, be sure to put a protective tube around the base of the vine. The weed whacker can cut through a plastic tube over time if you keep using it around the base. Be careful that you’re not just burning through these plastic tubes and keep in mind that even the most skilled worker can hit a trunk occasionally.
6. How do I choose the best cane to be used for trunks?
Find good round wood, that’s at least three-eighths of an inch all the way up to the fruiting wire where your cordons will be developed. Look at the canes and choose one that has the highest number of buds or shorter internode spacing to allow many options for training your fruiting structures.
7. How do I handle potted vines and when is the best time to plant them?
As long as the roots aren’t spiraling and bound in the pot, you can take that pot and use it to help keep the roots undisturbed going right into your soil. Over time, the roots will establish in your native soil. In terms of timing, it doesn’t matter the season, but the longer you keep those vines in the container, the more you have to maintain them. Potted vines need more frequent watering than vines that are in the ground outdoors. So the sooner you get them in the ground this winter, the less you’ll have to water them in the pots. But you also want to wait until after the last spring freeze if possible.
If you want to learn more about grape-growing tips and tricks, check out www.vineyardundergroundpodcast.com/vu013.