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Be aggressive at this busy time

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Be aggressive at this busy time

06/04/2017

Article taken from the Agronomist & Arable Farmer

Considering how dry the winter has been in my area of Staffordshire and Shropshire, I've been concerned to see how much Septoria is present in the bottom of wheat crops, even in varieties that are supposed to be more resistant to the disease.

There is also a surprising amount of mildew, and I've seen quite a bit of yellow rust coming in, especially on Reflection, where seed was not treated with fluquiconazole (Galmano).

It's not just down to variety - later-drilled crops look a lot cleaner.

T0 sprays have been tailored to variety and disease profile and should dry up some of this disease, but I expect it to return, so I'm planning T1 sprays accordingly.

I believe in going in hard at the start of the season. You can always hold back later if disease threat s don't materialise, but if you try to shave costs the job can quickly get away from you.

I'm recommending an SDHI­ based T1 to target Septoria, always the main disease in the wetter West, backed up with extra rust protection where needed.

I'll use bixafen + prothioconazole plus fluoxastrobin (Variano Xpro) to increase rust control. In all cases I'll maintain robust rates. I'll add a multi-site (chlorothalonil) at T1 to increase protection and as an anti-resistance strategy to help safeguard other components, particularly the SDHI.  I will also try the new Syngenta fungicide Elatus Plus (benzovindi flupyr) as the SDHI element for a comparison.

Most of my wheats had a growth regulator penned in at TO canopy. I'll boost that at T1 with chlormequat + Optimus (trinexapac). I prefer a split dose approach - applying a higher rate in one hit during April is a bit of a sledgehammer approach and can set crops back if it turns cold.

Oilseed rape growers will soon be facing the annual Sclerotinia dilemma - should they be using one spray or two? For me there is no debate - I'll use two cheaper applications rather than one expensive one to ensure the crop gets five to six weeks' protection . With oilseed rape worth about £350/t it's even more of a no-brainer than usual.

We can't see the disease so have to rely on forecasts. However, often by the time these raise alarm bells it's too late and the disease has taken hold.

Sclerotinia gets into the plant if spore release from fruiting bodies in the soil coincides with petal fall during wet conditions. Petals stick to stems and leaves and spores colonise the decaying material, then enter the plant. Fungicides are protectant only, so we have to keep ahead. The early flowering spray will be based on picoxystrobin (Galileo) followed up with fluopyram + prothioconazole (Recital). I'll use half to three­ quarter rate depending on conditions. If the forecast is warm and wet, I'll increase the dose.

We need to keep a sharp eye out for weevils on peas and beans. Adults feeding on leaves are not the problem - it's the larvae that feed on roots that do the damage. A pyrethroid spray should be used once damage is observed.

Potato crops will receive two pre-em herbicides. The first residual will go on 10 to 14 days post-planting onto settled ridges, based on prosulfocarb (Defy) and metobromuron (Praxim). Linuron is going so we need to move on - I've been using metobromuron for the past two seasons with very good results. I then follow at emergence with a contact to tidy up any weeds that have come through.

Any fodder beet growers still to order pre-em herbicides should do so soon. The sugar beet area could bounce back this season, so chloridazon and metamitron could be short.

These pre-ems are essential - they sensitise weeds to the first post-em spray and maintain flexibility for the programme  ahead.

Luke Hardy is an agronomist for Agrovista based in Staffordshire/Shropshire (luke.hardy@agrovista.co.uk)