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Phylloxera on Frontenac – Management options

Last week I observed the first phylloxera galls on Frontenac, with shoots out 4-6 inches and 3-4 leaves.  These galls each contain a single female phylloxera that came out of an egg overwintering in bark crevices on the trunk.  As the gall matures, the female (attached to the leaf inside the gall) will lay eggs in the gall, which will hatch into ‘crawlers’ that move up to the shoot tip and attach themselves to leaf tissue and form more galls.

Phylloxera gallsHow concerned should you be about these galls?  My rule of thumb for phylloxera is that the need to treat your vineyard with insecticides against foliar phylloxera has to do with how early it comes out.  If you see the first galls later in June or early July when there are already 12-16 leaves on each shoot, then the galls will make the shoot tips ugly, but not have a material effect on vine function.  However, early appearance of these galls this year suggests that new galls will continue to be produced, and control measures would be justified.  It’s a good idea to take a look in your vineyard, and see what is out there.  Keep in mind that different varieties have different susceptibility (Frontenac is highly susceptible, la crescent and Marquette less so) – and that they may be unevenly distributed.

What are the options and timing?  There are four insecticides listing grape phylloxera in the NY/PA Pest Management Guidelines (see Table 4.2.1 ).  Two of them –  Admire Pro (imidacloprid) and Danitol (fenpropathrin) – are restricted use pesticides and require a certified applicator license.   The other two, Assail (acetamiprid) and Movento (spirotetramat) are not restricted use materials, but have different properties and costs.   Assail has performed well in small-scale trials here in NY, with similar effectiveness as Admire and Danitol.  It has a fairly limited residual action (eg. a week or so), so one may need to repeat application 10-12 days if galls return.  I’d advise giving the vines another week or so before attempting an application.  This will be most effective against the ‘crawlers’, and less so against existing galls. Movento is a new product that has long residual activity (several weeks) and is translocated through the vine. Because of this, it should have activity against the adults in the gall (they will ingest while feeding). It will be the most effective material for foliar phylloxera – but is expensive. Entomologist Greg Loeb advises that one should wait until there is sufficient canopy (18-24 inches showing) before attempting an application.  

Costs.  One dealer in NY quoted cost of an Assail (2.5 oz) application at about $13/application, with 2 applications that would be $26/acre.  Movento (at 8 oz/acre) would cost about $65/acre – but may offer longer lasting control.  It is apparently now sold in quart sizes (about $260/quart), which is more manageable than the gallon containers exclusively offered last season.

Always scout for insects.  Unlike diseases, above-ground insect feeding will always be visible in your vineyard (eg. like these phylloxera galls).  Always go out and scout your vineyards before applying any insecticide.  If you don’t see evidence of insect feeding or injury, then don’t waste your money applying insecticides for pests that are not there. 

 

Comments

15 Responses to “ Phylloxera on Frontenac – Management options ”

  • Judi Yockel

    I have 6 Cabernet sauvignon plants that I planted 2 years ago and last summer the phylloxera galls appeared late in the season. What can I use as a small homeowner grape grower to kill the bugs?

  • tem2@cornell.edu

    Phylloxera leaf galls are uncommon on Cabernet sauvignon. Personally I wouldn’t worry about killing them. They may not overwinter, and populations tend to fluctuate. I don’t know of any ‘homeowner’ type insecticides that will really do much to them (They are protected within the galls, and only susceptible when the ‘crawlers’ appear, and before they attach themselves to a leaf.) Late in the season = little impact on productivity, ripening.
    You may also want to check with your local university extension office.

  • tem2@cornell.edu

    You cant. what you see is the aboveground phase of an insect that also lives on roots. Cabernet Sauvignon on rootstock should be resistant, and the foliar galls, (to which CS is not normally very susceptible) may look ugly, but if they come on late in the season they don’t affect the grapevine or crop much at all. Insecticides are iffy (they are protected within the galls), and if I had 6 vines I’d just live with it. Not going to impact your vines much.

  • Dave Clabault

    I have 4 Frontenac vines that are heavily galled with phylloxera. The galls started showing up in mid-to-late May. What, if anything, can/should I do?

  • tem2@cornell.edu

    Hello – If you are a backyard grower and only have 4 vines, I wouldn’t worry about it. I described insecticide options in the post, and for commercial plantings, I recommend scouting until you see the first galls on the shoot tips, then applying an insecticide IF its early in the season and the canopy is still developing. If it is after fruit set, when shoots already have 10-12 leaves on them, I’d let it go, as it has no impact on the fruit (Just on foliage, and if you already have a fully developed canopy it will just make the shoot tips look ugly, but won’t impact pre-existing leaves).

  • NK Araway

    I have 70 vines, including Frontenac, Marquette, St. Crois, Petit Pearl and Briana as a home vineyard. My vines are young, and this is my first fruiting year. I lost 3 vines over winter, and this summer have been infested with leaf phylloxera that affected primarily new growth after fruit set. I’ve been pruning off the affected growth as much as possible, with the opinion that whatever doesn’t hatch in my vineyard does not contribute to the problem. Is there anything I can use to kill these things?

  • tem2@cornell.edu

    Here’s some tips:
    1. Phylloxera is a native insect. You are not going to get rid of it or materially affect it by removing leaves. (its also on roots and wild vines).
    2. I wouldn’t be very concerned about phylloxera after fruit set. Most of canopy is out by then, and if you have 10-14 intact leaves (and keep them healthy and disease free), that’s enough to ripen the grapes.
    2.5 Spraying now is not going to have a huge effect on what happens next year.
    3. Insecticides: Movento and imidacloprid are both effective, but I wouldn’t put it on this late in the season. (Consult the Midwestern spray guide, available online. Unfortunately ours is no longer available online)
    4. Next year: pay attention to shoot tips. When you see first galls is the time to apply insecticides. If you don’t see anything until after fruit set, I wouldn’t worry about it.

  • Richard Mccann

    Help.Early season here in Eastern Canada and phylloxera(leaf) has hit really hard on 5 year old vines and last years plantings. Out of 2 acres i guess 25% has been affected. Grapes are 2 weeks away from forming so this is a nightmare. Any suggestions?

  • Michele McHugh

    We have 2500 vines of different varietals. We’ve noticed a heavy infestation of phylloxera, especially on the frontenacs. Do you recommend spraying?

  • Elizabeth

    I’ve found some wild grapes recently at my new home which has a creek running in the back. Unfortunately, it seems that is has a bit of phylloxera. 🙁 If anyone can answer my questions that would be very appretiated.
    1) Is there any way I can get rid of the pest?
    2) Can I use GRAFTING to grow some grapes elsewhere, or has the whole vine been affected and the phylloxera won’t go away?
    3) Are grapes with phylloxera safe to eat? Are they poisonous or do they not really affect the grapes that do ripen?
    4)The plant doesn’t seem to be dying with the phylloxera, but can I pick the grapes that ripen? (That’s still kinda gross, though )

  • tem2@cornell.edu

    Phylloxera is native to the US. Wild grapes such as V. riparia are susceptible to foliar phylloxera. Grafting won’t change this.
    Phylloxera have no effect on the grapes, aren’t anywhere near the grapes, do not infect grape clusters.
    Yes you can pick the grapes. Wild grapes will generally be small with little pulp. Make good jelly, but not the greatest to eat.

  • tem2@cornell.edu

    First, please use the word ‘variety’ for grapevines. ‘varietals’ refers to wines made from one grape variety.
    Frontenac is susceptible to foliar phylloxera. Yes, sometimes it is advisable to spray. But that is generally early in the season (I feel that if the infestation starts after each shoot has 10-12 leaves, it will have little economic impact on fruit ripening) which for me means before fruit set. Scouting helps – if phylloxera present early, will pay to spray – but do it early.
    The original post describes management fairly completely.

  • tem2@cornell.edu

    Calm down. This is something less than a disaster. Even with heavy infestations, vines seem to tolerate foliar phylloxera without any lasting damage. Insecticides can help (see original post) – impact might be greatest on youngest vines without a well-developed root system. Suggest you read up on the pest and its management. Resources
    http://articles.extension.org/pages/31606/grape-phylloxera-foliar-or-aerial
    http://www.virginiafruit.ento.vt.edu/phylloxera.html

  • Charlie

    I’ve used wild grape as a seasonal privacy fence interwoven through chain link. This year there is a heavy infestation of phylloxera, I mean heavy. Where can I purchase Bayer’s Movento for the homeowner? Not by the 55 gallon drum, know what I mean? Thank you.

  • tem2@cornell.edu

    I don’t recommend using insecticides for cosmetic damage. Phylloxera waxes and wanes over the years. Just because you have a heavy infestation this year, doesn’t mean it will repeat next year. I’d suggest you live with it. For commercial growers, I recommend treatment only when it comes on early. If there are 10-12 leaves to feed the fruit, I recommend they ignore what happens at the shoot tip. Movento is not for homeowners. It costs about $800 per gallon or so.

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