Growers are advised to continue checking sugar beet crops for aphids – and treat accordingly while abiding by application guidelines.
The first peach–potato aphid (pictured) catches of 2022 were reported in mid-April, with green wingless aphids increasingly found afterwards in sugar beet crops which hadn’t been treated with Cruiser (thiamethoxam).
Last month, the British Beet research Organisation said growers should check non-Cruiser treated crops as a priority and consider spraying if above the threshold of one green wingless aphid per four plants up until the 12-leaf stage.
Current foliar spray options are Certis’ insecticide InSyst (acetamiprid) or flonicamid – with one application of each permitted per crop. Growers should use InSyst first, recommends Certis technical specialist Henry Welham.
“Its rapid knockdown prevents early virus build up which has the greatest impact on yieldm” he says. “InSyst has also shown good persistence in trials keeping aphid numbers very well controlled for two weeks following treatment.”
The application window for InSyst is BBCH 12 (first pair of leaves unfolded) to 39 (crop cover complete). But there is an additional rule if it is applied between BBCH 12 and 19 (nine or more leaves unfolded) – as has been likely this year.
This label restriction means acetamiprid must not be applied to the same field until the second spring after it has been applied to a sugar beet between BBCH 12 and 19, says Mr Welham.
There had been no reports of wingless aphids on Cruiser treated crops by early May. Growers who need to spray, if above threshold, they must start with flonicamid, the active ingredient in the insecticides Teppeki or Afinto.
The BBRO aphid-monitoring network is now active and available on BBROplus. Growers who haven’t yet done so should enter their email address and their British Sugar contract number to validate registration on the BBRO website.
Once registered, growers have immediate access to BBROplus. Their contract number is only used once to validate access, with no permanent record kept. The website address is www.bbro.co.uk.