A moderately high virus yellows forecast suggests careful use of foliar insecticides will be required this spring. CPM finds out their key characteristics.
“Inspect crops at least twice a week when the risk period starts and make sure you have at least one aphicide in store at the beginning of the season.” ALISTAIR WRIGHT
By Mike Abram
Foliar insecticides remain the key in-season tool for controlling aphids that transmit virus yellows to sugar beet. With a forecast higher risk season than last year, having three licensed active ingredients available should make putting together control programmes a little simpler, believe experts.
Rothamsted Research’s initial forecast predicted aphid migration will begin around 22 April in the eastern factory region, although it could be as early as 5 April or as late as 9 May, depending on weather after 1 March. In the region around the Newark factory, the risk is lower with migration predicted for 2 May, again with around an 18-day window either side.
Understanding aphid behaviour is important because in the absence of any other control measure, virus yellows infections are forecast to hit up to 62% of the beet crop in the eastern region, and 49% in the Newark area from a typical 30 March planting date.
Forecasts are being updated weekly as new weather information becomes available, stresses Dr Alistair Wright, BBRO head of crop protection. “Warmer weather earlier in March brought the anticipated first flights forward by a couple of days, so check BBRO’s website for the latest information.”
Earlier aphid flights are particularly problematic for later drillings, when the crop is still very small or even still being drilled, he notes. “Then it becomes a case of being very pragmatic with aphicide choices to make sure you’re getting the most from them.”
With three active ingredients, and multiple products available, growers have more choice than in recent seasons, when Emergency Authorisations had to be sought for a third option. Each of flonicamid, acetamiprid and flupyradifurone have slightly different characteristics, raises Alistair.
“Flonicamid, which most growers will know as Teppeki although there are other products available now, is a true aphicide. It’s very selective but knockdown is slow as it disorientates the aphid and causes them to cease feeding within a day or two of application,” he explains.
“That’s why you might still see some live aphids after spraying, but they shouldn’t be causing any harm if they’re no longer feeding.”
Flonicamid is relatively friendly to beneficial insects and offers good control in the long term. “As it isn’t translocated around plants particularly effectively, the best position for this active is on larger plants to offer better coverage and uptake,” suggests Alistair.
In contrast, acetamiprid – the Insyst range of products – has a very fast kill. “This is a true insecticide rather than a selective aphicide, so will take out pretty much all beneficial insects.
“A good position for acetamiprid is if you have just a few aphids in the crop early on, because it’ll quickly control them, preventing initial colonisation and preventing secondary spread of virus yellows.
“And then when beneficial insects migrate into the crop, normally when the crop is a little more established, the other two chemistries are more friendly,” he says.
The final option is flupyradifurone in Sivanto Prime, which was available in sugar beet for the first time last season. “This is more limited in its use,” reports Alistair. “It offers good knockdown quite quickly, however, the label does only state moderate control of aphids so you might see less of a reduction than with the other two products.”
With a favourable profile to beneficial insects, it could potentially be used at any point in the programme. “It’ll help when you have beneficial insects in the crop early on and you want to allow them to continue building. Potentially, using Sivanto Prime might allow you to get away with using fewer sprays.”
He highlights that there’s no set order to using each option, although both acetamiprid and flupyradifurone are Group 4 insecticides so have a similar mode of action. “Ideally, you’d want to break up applications with a flonicamid in between.”
The choice of which to use first might come down to whether there’s already a building population of beneficials in the crop. If so, Sivanto Prime might be the better option, while if it’s still too early, then an Insyst product makes most sense, with a flonicamid product in the middle, proposes Alistair.
“Inspect crops at least twice a week when the risk period starts and make sure you have at least one aphicide in store at the beginning of the season,” he stresses. “Then you’re ready to go when aphids do hit the one-aphid-per-four-plants threshold, in a timely fashion.”
That threshold lasts until the crop reaches 12 true leaves, when it changes to one aphid per plant.
BBRO will continue to provide regular monitoring updates through the season on its website with 20 BBRO Crop Watch sites gathering data from yellow water pan traps, and a further 20 sites also monitored by British Sugar agricultural managers through aphid counts on plants.
“We’ve also borrowed a suction trap from Rothamsted to use at Morley in Norfolk. That’s primarily to do with our StatBeet project investigating whether we require more suction traps or whether we can accurately predict aphid pressure in other regions using modelling.
“The suction trap will compare when aphids arrive in Broom’s Barn with Morley. The end goal of the project is to have localised forecasts to help improve on-farm interventions,” he reports.
Those interventions could also include some of the technologies BBRO is working on to deter or repel aphids, which have shown promising early results. “When used effectively, aspects like sprays that colour soils, or barley nurse crops can temper early infestation of aphids, but there are some challenges in how to make them practical for all situations.”
Meanwhile, the search for resistant varieties continues, points out Alistair. “This year’s variety trials have 10 novel entries, to look for new candidates to eventually join the four varieties with some virus yellow resistance currently on the 2027 Recommended List,” he concludes.
| Aphicide options for 2026 | |||
| Active ingredient | Flonicamid | Acetamiprid | Flupyradifurone |
| Products | Teppeki | Insyst | Sivanto Prime |
| Afinto | Insyst SG | ||
| Hinode | Insyst SL | ||
| Alakazam 500 WG | |||
| Velmeri | |||
| Kibera | |||
| Aphid knockdown | Slow | Fast | Fast |
| Target aphid species control | Control | Control | Moderate control |
| Impact on beneficials* | Mostly harmless | Generally harmful | Harmless to slightly harmful |
| *According to IOBC Toxicology classification. For species-by-species impact on beneficial insects see AHDB’s ‘Insecticides effect on natural enemies database’ | |||
Source: BBRO Fact File
This article was taken from the latest issue of CPM. Read the article in full here.
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