14 June 2001
Pest risk to late peas and beans
By Andrew Swallow
LATE pea and bean drilling means crops are at extra risk from pests and diseases, an expert has warned.
Growers are pretty sure to see rust on winter beans, says Anthony Biddle of PGRO research centre near Peterborough.
First fungicides may already have gone on, but a second application, should follow before crops are too tall, he advises.
This should include a triazole such as Alto (cyproconazole) or Folicur (tebuconazole), says Mr Biddle.
He advises growers to check for black bean aphid and mix in an aphicide such as pirimicarb if any are found.
Aphids also threaten pea yields through direct feeding and transmission of pea enation mosaic virus.
We are already finding pea aphids in crops, but have only found bean aphids on wild plants, such as thistles, so far, said Mr Biddle.
If you start to see aphids, do not wait — combat them there and then.
Approval for using Amistar (azoxystrobin) in peas looks useful, particularly its shorter harvest interval compared with chlorothalonils six-week requirement, he added.
First applications should go on at first pod, and may include chlorothalonil, with straight Amistar two weeks later if disease is visible or conditions are favourable.
Although more strobilurin fungicides are in pea trials, no extra greening effects have been seen so far.
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