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Agronomy FAQs


Every month, our Customer Technical Advisor, Caroline Linsdell, compiles a list of frequently asked questions based on the phone calls and emails she receives from growers and agronomists.


Read the latest questions below or browse the archive.

Can AMISTAR be used alone in cereals? The grower has already used a rust active triazole and didn’t want to apply another one!

The AMISTAR label states: AMISTAR must always be used in mix with an alternative mode of action, i.e., triazole/multi-site/SDHI, recommended for control of the same target disease that contains a fungicide from a different cross resistance group and is applied at a dose that will give robust control.

What is the interval between applying AXIAL Pro and a hormone-based product or an SU?

If AXIAL Pro is applied first, then leave 7 days before applying a hormone or SU, but if a hormone or SU is applied first, you must wait 21 days before applying AXIAL Pro.

Is it worth applying a HALLMARK Zeon for pollen beetle control in oilseed rape?

There are extremely high proportions of the pollen beetle population with pyrethroid resistance. Therefore if HALLMARK Zeon is applied and there is little/no control, use an alternative mode of action. Remember once the oilseed rape is in flower, the pollen beetle then becomes a beneficial.

NEMATHORIN stacking rings keep breaking, can the product still be used?

If the stacking ring breaks, the Surefills with product inside can still be used via the handles. The NEMATHORIN Surefill stacking rings are just that, stacking rings, they are not handles and should not be used as such.

Been hearing about QUANTIS, what is it and what is it used for?

QUANTIS is Syngenta’s new biostimulant, which contains a relatively high proportion of short chain organic carbon, as well as amino acids and potassium. It is being launched this season into potatoes. When potatoes are under heat stress, applications of QUANTIS have been proven to increase yield.

A presentation on QUANTIS from the recent Potato Science Live webinars can be viewed here

If an SDHI seed treatment already applied to winter wheat, how many application of foliar SDHI can be made?

An SDHI seed treatment does not impact on the number of foliar SDHI applications – therefore 2 foliar SDHI’s can be applied.

How late can spring barley be drilled?

Mid-April is the latest recommended cut-off. Beyond this the growing window becomes very short and yield will be affected.

Have yellow rust in GRAHAM and some other varieties with good adult plant resistance, why?

GRAHAM is seedling or young plant susceptible and therefore may well show yellow rust symptoms in early spring if the conditions are conducive. Treat early yellow rust infections in GRAHAM as you would in other varieties with appropriate fungicides.

Spring barley drilled at the end of March, should I be worried about BYDV infection?

Later drilled spring barley can suffer more from BYDV than autumn drilled barley. It is more serious in crops that have not reached GS31, and later drilled crops will not be at this growth stage at the time of aphid flight and will, therefore be at more risk of yield losses. Monitor crops for aphid flight, which usually start when temperatures reach ~11oC. Latest predictions can be found on the AHDB website

Spring barley is much shorter than winter barley – do I need to use a PGR?

Lodging is still a risk in spring barley and should be managed accordingly. Assess risk factors such as soil type, weather, crop density and varietal resistance. PGRs should only be applied to actively growing crops and over-regulation can result in yield and grain quality reduction. A “split” approach of low doses applied twice is often better than a single higher rate application.