South: Variable disease pressure in wheat

While T1 was hot on the heels of T0, with warm weather speeding the emergence of leaf 3, disease pressure has been variable to date. Wheats with higher septoria and rust risks received an SDHI + azole + chlorothalonil (CTL), lower risk varieties were treated with an azole + strobilurin + CTL.

Patchy showers have in places stimulated a flush of wild oats, perennial weeds, and polygonums in open crops. Now is a good opportunity to tidy these up along with volunteer potatoes.

In forward winter barleys, awns are just peeping out – don’t forget to check the latest safe growth stage of plant growth regulators (PGRs) if sprays are delayed.

There’s the odd spot of barley yellow dwarf virus (BYDV) in wheat and barley, limited to a few foci on treated seed that didn’t get a follow up insecticide until the spring. Micronutrient mixes will help mitigate the effects.

Mildew has appeared in winter oats, but has been largely checked by morpholine fungicides at T0; cyflufenamid will ensure control if it returns.

Oilseed rape is approaching full flower and pods are starting to set. Sclerotinia pressure is high, so ensure petals are protected before they fall. No insecticide has been required yet this season, but a bee friendly product such as Mavrik (tau-fluvalinate) for seed weevil is likely with the second petal fall spray – especially if a triazole is included.

Spring beans and peas are showing high levels of weevil damage at emergence and it’s important to limit larval grazing of developing roots during these early growth stages. Keep in mind maximum application limits per product and what will be required later to limit pea moth and bruchid beetle.

Spring cereals are now all up, but growing slowly due to low soil and night temperatures. The dry weather has limited weed germination and the efficacy of pre-emergence herbicides, but recent showers will reactivate the residuals.

Potatoes are emerging and field vegetables are getting underway. Whilst there’s no sign of aphids yet, cabbage and carrot root fly emergence is fast approaching in the South East.

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