CALL US
󰀑
888-767-7442
CALL US
󰀑 888-767-7442
󰀄

Recently I attended the annual Texas Pierce’s Disease Research Symposium conducted by Texas A & M’s Texas AgriLife Extension. Pierce’s Disease, also known as PD, is such a big problem for grape growers that many states have annual conferences and research projects devoted exclusively to it such as this one. There are several culprits for spreading PD, but the main demon is the Glassy-Winged Sharpshooter. They are little, but they come in swarms, biting and sucking into grapevines, leaving behind the nasty bacteria they carry in their mouths and flying onto the next vineyard spreading the disease. You can try and kill them, but more just come. And once a plant has the disease, there is no cure. Pierce’s Disease is all over Texas and the south, but proliferates in the Texas Gulf Coast region and slightly into the Hill Country AVA. PD has also been found in Oklahoma, New Mexico, Arizona, California, and many east coast and gulf coast states.

So, if you can’t fight the massive amounts of these flying pests, what can you do? Prevention. It’s all practice. Keep plants that attract the vector insects away from your vineyards. Often these are landscaping plants like Oleander, Crepe Myrtle, Magnolia, etc., as well as wild plants such as wild grapevines, sunflowers, and others. Tall weeds in the vineyard can also host these insects, so keep your weeds under control. In addition to keeping your vines away from these insect preferred plants, use insecticides that ensure if a Sharpshooter does bite one of your vines, it doesn’t survive to bite another one.

Physical Management. Watch for symptoms. This means walking your vineyards every couple of days during the growing season and deal head on with the insects that spread PD. These sharpshooters suck the plant juice, leaving behind the bacteria, merrily heading on to the next. If you find a vine with Pierce’s Disease – the only thing you can do is rip it out and quick! This kind of vineyard management works well only if your people are trained & know what to look for AND if you have the insects under control.

Use of Bacteria. Fight fire with fire, if you will. All living things have thousands of bacteria inside and outside of them, and the grapevine is no different. Bacteria breeds & propagates until it reaches a “certain” amount. It’s a stealthy process and only the bacteria know when this “goal” is attained. Once they hit this “goal”, the bacteria switches from reproduction mode to “attack mode.” This is happening with all kinds of bacteria. A lot of competition is going on between the various bacteria. One bacteria is trying to fight off the other bacteria. Question: Is there a bacterium that can go head to head with the PD bacteria? The TexAgri Extension is testing inoculating the plants with PD fighting bacteria. Too early for results at this time.

Breed Resistant Plants. Another tactic being tested is deciphering the genes of plants and breeding them with PD resistant plants. They are looking at what genes are different in the parents and the new bred plants. This will take a few years to test still and they don’t know what kind of grapes will actually grow and how good the wine will be once harvested. Some of the new breeds planted now are children of Chardonnay & Cabernet. Now we wait.

Plant PD Resistant Grapes. Focus on the grapes that work well in your region. Most of the vinifera used the United States to make wine is from Europe. European plants are not resistant to Pierce’s Disease. Ironically, North America has the most wild grapes in the world. We could learn from some of the AVA’s that are combating PD by planting resistant grapes. The Texas Gulf Coast, with a high PD area, is having very good success with Blanc du Bois and Black Spanish/Lenoir. These grapes make excellent blenders, each acidic and the Black Spanish having some great tannins and color. We could do the same thing with these two grapes as they do with Petite Sirah in California in Cabernets. Because Blanc du Bois and Black Spanish are great blenders, the we could be producing the staple grape for Texas that allows all the other grapes the ability to stretch and make premium wine blends.

Research into Pierce’s Disease has made great strides in the last 10 years. At this point we have cultural practices that allow control of disease spread, and hybrids which are resistant to the disease. On the horizon we can see resistant varieties and even a vaccine.

As we gain more control over Pierce’s Disease, what do you think is the next biggest challenge facing grape growers?

  1. April 23, 2011

    Recent relevant article posted in Wines and Vines 4/20/11 re: PD in Texas http://bit.ly/i4bHho

  2. January 21, 2013

    Special Edition: Pierce’s Disease in Texas, A Ten Year Perspective 2010 http://bit.ly/WmTz6O

Comments

Write a comment:

*

Your email address will not be published.

Copyright © 2013
󰁓
󰀰 󰀩 󰀭 󰀎