Aphids in dd

[Dan Powell]

I think natural balance is the key but not easy to achieve. You are never going to get rid of aphids but you want their levels kept below a level that will cause economic damage. Easier said than done. I know Simon Cowell left off autumn insecticides a couple of years ago. Not sure whether he tried it last year

Maybe it's necessary to grow a "trap crop" in strips adjacent to your cash crop or even as a companion to it. Something more desirable to the aphids than the cash crop. Then your beneficials maintain the aphid population at a low level that means they tend to stay in their preferred environment. Using the carrot not the stick if you will?

 

[Richard III]

I left a field unsprayed and no seed dressing 2 autumn's ago. There was bydv to be seen every where locally, my field was fine.

This year all the wheat is home saved, untreated. Just haven't decided how brave/foolish to be this time yet.

 

[combineguy]

Hi

Aphids are amazing insects.

They can be born three ways. With wings, with out wings and pregnant

 

[Andy Howard]

Hi



With wings, with out wings and pregnant

Sounds like the girls you meet on a Saturday night in Ashford

 

[Simon C]

Last year what little winter cereals I managed to establish didn’t get an insecticide because it was to wet to travel and there was no BYDV. It was not a BYDV year and the spray would have been unnecessary anyway.

Go back two years to the Autumn of 2010, like some of you on here, I was wondering if no-till, with it’s inherent better biology and therefore wider availability of nutrients, would make the plants less attractive to aphids. So my strategy was to leave one or two tramlines in every wheat field without any insecticide. There was no BYDV anywhere.

In the Autumn of 2011, armed with the previous years “success”, and feeling pretty reckless, I decided to ignore my agronomist and leave the insecticides on the shelf, where they remain to this day. DISASTER. My two earliest drilled wheat fields were infected with BYDV. The first one, luckily only 16 acres, had probably two thirds of the whole field looking yellow and plants dead. It was obvious from the yellow patterns across the field that the aphids had blown in from an adjoining grass field by the prevailing wind.

The second field to be drilled had random patches across it, but mainly around the headlands where aphids had migrated from the banks and hedges. Expecting the rest of my wheat to soon go the same way, I was totally distraught by what by what I had done, how could I have been so stupid? I was expecting two groups of farmers visiting from France and Denmark in the Summer so thought I would have to cancel them because I was so ashamed of my incompetence.

Two weeks passed and it became clear that the rest of the farm, being a little later drilled, was not infected at all, even though it was what we now know as the worst BYDV year for a long time. So not quite the disaster I first envisaged, about 80% of my wheat was OK.

Now the interesting bit
It was now too late to spray off and grow something else, so I decided not to spend any more money of the 16 acres, except to put on some foliar nutrition and harvest what ever I could. Gradually the crop started to recover, green began to return to the yellow leaves and stems, and leaves two and flag came out looking completely normal. Somehow, with a complete array of nutrients available to the plants, they were able to fight of the virus. I did loose a lot of tillers, so the crop was quite thin at harvest, but it did produce some nice looking ears and yielded about two thirds of what I would have expected.

Assuming prevention is easier than cure, I would have thought this proves that healthy plants shouldn't succumb to the virus, even if there are a few aphids about.

So a few lessons learnt
With something as random as BYDV, one year in five or one in ten, you can’t draw any conclusions from one off, farm based trials.
Wheat growth stage and weather conditions are crucial to the spread of aphids and the virus.
Nutrient status of the plant is directly related to the plants ability to defend itself and fight off the virus. Maybe an Autumn tissue test and foliar application of any deficiencies could be used as a preventative insurance, rather than insecticides.


As for this year, to preserve my sanity, I think I will be using the insecticides that are still on the shelf. Mavrik, not Cyper, as it is supposed to be safe on the predators, although I think they are killed by eating dead infected aphids.

 

[rob1]

Hi Simon what were the drilling dates in 2011 of the crop that escaped the virus?

 

[Richard III]

From the data I have seen, despite the mild autumn aphid numbers are still below the 10 year average, due to lower aphid numbers this summer. The weather from now on will probably make a big difference and by the way it's going I may struggle to spray any way.

 

[Simon C]

Hi Simon what were the drilling dates in 2011 of the crop that escaped the virus?

Rob
Can't remember exactly but the infected crops would have been drilled arround the last few days of September and the rest probably a week later. It's not the actual date that matters, every year is different, but the small variation in development stage seems to be crucial.

 

[rob1]

Rob
Can't remember exactly but the infected crops would have been drilled arround the last few days of September and the rest probably a week later. It's not the actual date that matters, every year is different, but the small variation in development stage seems to be crucial.

Had you used deter? always have used that to give me some cover, does that harm the beneficials as well, would love to be able to give up all insecticides

 

[Simon C]

Had you used deter? always have used that to give me some cover, does that harm the beneficials as well, would love to be able to give up all insecticides

Home saved seed had no Deter or fungicide dressing. Last year with all the Fusarium infested seed and the previous years BYDV scare, I ended up using Redigo Deter. I don't really like fungicide seed treatments at all for other reasons, the ideal would be Deter on it's own, but that's not available.

 

[rob1]

Home saved seed had no Deter or fungicide dressing. Last year with all the Fusarium infested seed and the previous years BYDV scare, I ended up using Redigo Deter. I don't really like fungicide seed treatments at all for other reasons, the ideal would be Deter on it's own, but that's not available.

Thanks thats very interesting, may do a bit of a trial here this year

 

[shakerator]

As for this year, to preserve my sanity, I think I will be using the insecticides that are still on the shelf. Mavrik, not Cyper, as it is supposed to be safe on the predators, although I think they are killed by eating dead infected aphids.

how much more ££ is mavrik @Simon C ?

not sure how this unsettled windy weather will be affecting things.

 

[Simon C]

how much more ££ is mavrik @Simon C ?

not sure how this unsettled windy weather will be affecting things.

Sorry Shaker, don't know. Still got the stuff on the shelf from two years ago and paperwork from then is still at the accountant. Wouldn't have thought it is much more, cyper is next to nothing anyway.

 

[franklin]

Mavrik £34/litre last year. 240g/l tau-flavinate.

 

[marco]

What rate per ha?

 

[franklin]

Last time I used it in autumn it would have been 125ml/ha, or perhaps 120ml. That would be as a later, single dose for BYDV.