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Aphid predators

Discussion in 'Direct Drilling Crops & Agronomy' started by britt, Nov 14, 2017.

  1. britt

    britt Member

    Location:
    leics/warks border
    I have had a recommendation to spray aphids in wheat to prevent BYDV, as I expect many of you have.
    I avoid insecticides for all of the usual reasons, but it seems this one is needed.
    So what aphid predators are there about at this time of year that may be harmed ?
    I don't think there are many ladybirds about, never mind there larvae.
    Is an insecticide at this time of year as benign as it can be ?
     
  2. shakerator

    shakerator Member

    Location:
    LINCS
    Ants/flies

    i wouldnt omit it judging on aphids seen here!
     
  3. britt

    britt Member

    Location:
    leics/warks border
    I thought that ants "farm" aphids for the honeydew, so are more likely to protect than predate them.
     
  4. shakerator

    shakerator Member

    Location:
    LINCS
    Indeed but they also subdue colonies and stop them flying and in effect limiting secondary spread of BYDV as they need them close by......

    Nothing seems black and white in this game ....:confused:
     
    martian likes this.
  5. britt

    britt Member

    Location:
    leics/warks border
    We are already getting mole hills in notill fields, we don't want ant hills too. The combine driver would grumble a bit.
     
  6. rob1

    rob1 Member

    Location:
    wiltshire
    did you use deter dressing ? Not used an insecticide for many years and have lots of grass around for green bridges but no issues (so far)
     
  7. britt

    britt Member

    Location:
    leics/warks border
    No Deter. Most seed is cleaned only.
    Most years there is very little threat from DYDV in Oct sown wheat. But this year has been exceptionally mild and aphids can be found in crops.
    I haven't sprayed for them or had a problem with BYDV for years.
    This is threshold lead, rather than "just in case". (But I'd still rather not taking the longer term view).
     
    rob1 likes this.
  8. If we get any amount of cold weather average temperature below 4.8 c the aphid will not multiply
    They will also go down the plant and be harder to kill with inscecticide
    The aphid predictors will run into hundreds of species spiders and parasitic wasps etc
    They will reduce the aphids to a very low level this combined with the weather will eliminate the problem especially if you have not used inscectide for a few years

    In the 1990s i often found aphids in December but found very little bydv in unspraued fields so have not sprayed in the autumn since then rape or wheat

    In the 1980s when bydv was a big problem it was in wheat that had emerged in mid September

    If I farmed where temperature was higher west of the m1 then I waoild use seed dressing that would cover to the end of November
    The worst case were always where ploughing grass or wheat and emediate drilling followed with emergence of the wheat or barley before the volunteers had died

    With notill drilling wheat on the green the brassica aphids do not pose a threat and the beneficials are more numerous

    Nowadays the areas of spring land round here are a sink for cereal aphids and also help to build up beneficials compared to burnt of stubble with bare fields so the aphid moved onto the newly emerging wheat
     
  9. Wait till the spring march and if aphids build up more consider spraying
    the aphids on the crop now will stay put and have infected the plant they are on if we get cold enough weather they will die or the beneficials will get them killing aphid now will only be revenge killing
    They need enough day degrees to multiply temperature to average more than 4.8 c to accumulate day degrees

    If you look at fields on a sunny day the amount of spiders is staggering when a field is unsprayed
     
    rob1 likes this.

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