101-14 root stock resistance to phylloxera compromised.

Nodosities on 101-14 root tips.

Nodosities on 101-14 root tips. (From UC Davis Vineyard Views Newsletter)

UC Davis scientists have found phylloxera infestation of rootstocks bred to be resistant to the louse.

The 101-14 rootstock is a riparia-rupestris cross intended for heavy clay soils (see Herrick Guide, here).

Ironically, while 101-14 was found to be best adapted to heavy clay soils, this is the type of soil the louse prefers and the type in which the infected vines are planted.

Other signs of phylloxera (illustrated in the newsletter) are leaf galling and canopy growth stunting.

The newsletter does note that more study is needed to see if fungi are contributing to the root stock’s newly-found susceptibility.

Anyone about to plant a new vineyard, may want to hold off on 101-14 root stock and choose another type.

If vines with this root stock are already in the ground and symptoms are seen, treating with systemic doses of imidacloprid (injected into irrigation or poured on the soils and watered in – see labeling for Provado or Admire) may be helpful. The same can be done as a prophylactic measure.

As phylloxera is susceptible to imidacloprid, foliar application of appropriate concentration (see package labeling) should eliminate leaf galling.

Details should be obtained from the UCD-IPM site or from a local Cooperative Extension Offices.

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About SUAMW

Father, husband, physician, amateur guitarist, wine lover, wine writer, wine grower and wine maker trying to do it all within eye shot of downtown Los Angeles. http://www.shutupandmakewine.com http://twitter.com/Dr_Arthur_P
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8 Responses to 101-14 root stock resistance to phylloxera compromised.

  1. Frightened Turtle says:

    Interesting. I am in 2-4 feet of clay and silty soil on top of bedrock. Its a hilltop/hillside so is well-drained. I use 1103P and will be including110R in next years plantings. 101-14 is supposed to be highly resistant to phylloxera…

    • SUAMW says:

      Yeah, According to my friend Jeff Miller (Artisan Family of Wines), 101-14 is a real workhorse and is planted extensively. If much of that is in heavy clay soils, we could be looking at another AxR-like situation.

      • Kipper says:

        AxR1 was half vinifera and the risks of its inevitable decline were ignored. This situation is entirely different and in some ways, more disconcerting.

        MG 101-14 is a hybrid of two highly resistant American vines, which begs the question: which rootstock is next?

        • SUAMW says:

          Hi Kip,

          I’m curious: what is the degree of resistance of pure riparia or rupestris vines? Is it complete resistance by which the louse does not even touch the vines, or is it an ability to thrive despite being infected?

          I suspect it is the latter. Here is a picture wine blogger Jamie Goode took of a rupestris plant at a nursery in Spain: http://sphotos.xx.fbcdn.net/hphotos-ash4/s720x720/391327_10151869329855442_1121430744_n.jpg

          Of course, the riparia-rupestris cross could have eliminated or altered the trait that gives total resistance. There may, of course, be an additional factor which could be affecting the rootstock thereby creating an opportunity which phylloxera exploits.

          Then again, there is no reason why Daktulosphaira vitifoliae/Phylloxera vastatrix could not have mutated.
          I would watch the UCD site for more updates in the future.

          • tomas says:

            My understanding is that Phyloxerra lives on native roots, but the population does not explode, implying that native vines have some sort of growth inhibitor that prevents actual vine collapse even in the presence of the bug.

            I would be not be in a hurry to plant 110R in the above mentioned scenerio (clay soil over bedrock) for 2 basic reasons. Firstly, 110R is slow to establish in clay soils and you must be careful not to let the soil dry out or it will shut down the vines until next year. Secondly, 110R likes to root deeply and hates wet feet, so why plant it in soil that is shallow or high in clay?? You say your site is well drained, I have seen plenty of supposedly vigorous 110R shut down in clay soil under stress.

            If there is any truth to this new finding it will rock the industry. Here in Napa Valley, planting 101-14 on a VSP at something like 4X6 is a key part of the “Napa Cab” recipe. It would mean that many of the newly planted vines since the 90’s will be coming out again. It will also mean more reliance on 110R. Great, so we can all grow clone 7 on 110R, pick overripe, and act surprised our wines all taste the same.

            • SUAMW says:

              Thanks Thomas. As you can see in the article I linked to, there is more than symbiotic or saprophytic existence: The affected vines appear to have stunted canopy growth.
              You are not the only who appreciates the potential impact of this finding.

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