Recently by Will Foss

Rain in early November and some perfect spraying conditions subsequently have resulted in rapid blackgrass emergence in wheats and a considerable amount of Atlantis/Horus (iodosulfuron + mesosulfuron) being applied. Soil moisture has also activated the residuals to the extent that the later sown wheats contain some sick looking blackgrass.

There is still some follow up Atlantis/Horus to be applied and while conditions remain suitable, with soil temperatures still around 10C, it will be sprayed if conditions allow. In some cases larger and more difficult blackgrass warrants the addition of a contact + residual partner.

Wheat crops are a mixed bag with some very lush crops plastered in mildew and some of the earlier drilled crops still struggling to emerge.  Barley tends to respond to an autumn fungicide in such circumstances more than wheat, but there has been some mildewicide applied to struggling wheats especially on lighter and chalkier soils.

A lack of rainfall is continuing to cause problems, especially for later drilled and second wheats. Earlier drilled cereals have generally established well and are at early tillering stages. Dry seed-beds have resulted in variable performance from residual herbicides and in some places SU grassweed herbicide treatments have already been made. 

If conditions remain relatively mild there may yet be more Atlantis/Horus/GF-2070 applied this autumn. In some cases a non-SU 'holding' treatment is being used to increase control of emerging grass weeds with a view to tidying up in the spring with SU chemistry.

There are a lot of patchy wheat crops about and I suspect some that will never produce a fully established crop. Likewise weed emergence is also patchy making herbicide decisions difficult. In these situations it has been a case of protecting the emerged crop against aphids - if they have not been treated with Deter - and applying some manganese. Where volunteer beans have come through, these have also been dealt with.  

The hot dry weather in September has caused many questions to be raised about crop management. Much of the wheat drilled in early to mid-September went into excellent seedbeds. As soils have dried since then seed-bed quality has declined but pre-emergence herbicides have continued to be applied unless seed coverage has been inadequate.

Some farmers are now waiting for rain before continuing to drill. If seed is going to be sown into dry seedbeds then seed rates should be based on likely emergence date and not on drilling date.

Where bad blackgrass fields have been left for slightly later drilling blackgrass has been emerging, allowing a proportion of the population to be burnt off with glyphosate before drilling. I suspect the main flush will occur when we eventually get a decent rain.

Where cereal crops have emerged and seed hasn't been treated with Deter a foliar insecticide is due to catch the first migration of aphids into fields. These warm, settled conditions at the time of writing are ideal for aphid movement.

Catchy weather is dragging harvest out in some cases, affecting field work for following crops. Although many growers completed harvest during better weather at the very beginning of September there are still fields of wheat, beans and spring barley to cut at the time of writing.

As a result there is a wide drilling window for oilseed rape, from early August-drilled crops at 3-4 true leaves to seed still in the bag. Rape that has been sown has established well with plenty of moisture and have been treated pre-em, or more commonly post-em, with a residual herbicide plus graminicide where volunteer cereals have emerged with the crop.

Phosphate deficiency is visible on low P index soils and areas of fields.  Where DAP or an NPK fertiliser hasn't been applied in the seedbed these crops are being treated with foliar phosphate products to improve rooting and canopy expansion.

Desiccation of oilseed rape crops is well underway with only the later-maturing varieties and fields remaining.  Most have been treated with glyphosate plus pod sealant. Harvest should be relatively straightforward, as most crops are shorter than normal, providing they desiccate evenly.

The June rain has helped fill seeds and pods, although there are noticeable areas of pod abortion, especially in lower lying areas of fields and poorer soils. Hopefully, pod fill will have compensated for some of this early pod loss.

So far its been a bonanza summer for aphids. They have moved into every crop I have looked at. Despite being easily found in wheat in most cases they haven't reached threshold for treatment.

Most spring crops have needed spraying with pirimicarb and peas and beans are still being treated where infestation is occurring. Ladybird adults and larvae are helping to mop up large numbers of aphids and in some crops are keeping a lid on populations.

Some rain has appeared at last within the past couple of weeks - enough to potentially encourage disease development. Any crops with reasonable yield potential are being topped up with a T3 treatment to extend the period of protection and try to maximise green leaf retention and increase grain fill. 

In milling wheats, the T3 is also targeted at fusarium as the dry spring has been conducive to F culmorum development which has been climbing up the leaf layers as confirmed by monitoring sites. The risk of subsequent disease development on the ear is increased by wet weather.  Also yellow rust is likely to become more active with increased leaf wetness so susceptible varieties will also be candidates for a T3 top-up fungicide.

Grassweed control has generally been good where stale seed-beds and pre-emergence residuals were successfully utilised in the autumn. Early autumn Atlantis (iodosulfuron + mesosulfuron) treatments worked well, but conditions for spring applications were not always ideal. 

Crop stress is evident across the board although earlier drilled autumn crops on heavier land are fairing better.  Winter wheats are reacting to the dry conditions and lack of nitrogen uptake by moving rapidly through the growth stages with many flag leaves now emerging or emerged.  The final dose of nitrogen has generally been applied although knowing how much to apply has been very diffcult to calculate.  Where urea was used in March and April an estimate of nitrogen volatilisation has been made but this has generally been offset by a reduced yield potential.

T2 fungicide decisions are being made in the context of high yellow rust risk across many varieties including some with a 9 rating for the disease which have nevertheless exhibited active yellow rust.  Its possible the 'Claire race' of yellow rust is the cause but this has not yet been confirmed.  This could explain the breakdown of single-gene resistance in Claire and related varieties.  In some UAP trials in 2010 yellow rust was responsible for the loss of 30% of yield in Robigus and over 40% of yield in Oakley.  Robust fungicide doses of triazole + strobilurin will be needed at T2 where yellow rust is a risk with intervals kept to a maximum of 3 weeks.  A top up fungicide at T3 would also be sensible to maintain yellow rust protection.  In the few varieties that aren't breaking down to yellow rust a combined T2/T3 fungicide may well be adequate considering the rapid speed of crop development.

At the time of writing we are expecting rain in the next couple of days - if it arrives management decisions on poorer winter crops and spring crops may be very different.  At the moment it is a case of trying to reduce stress on crops by applying foliar nutrients and fungicide where disease is taking advantage of susceptible crops.  In the main it is mildew that is putting pressure on cereals.  Where pesticides are being applied we are being careful to avoid tank mixing too many products and avoiding spraying during hot conditions.  The spring crop that impresses more than any other is sugar beet.  Considering the lack of rain most beet crops have established and continued to grow very well although weed control has been challenging.  Tight intervals have been required to keep on top of weeds.

This part of East Anglia received no more than 4mm of rain in March so the best input for crops - especially spring crops - would be some decent rainfall.  Nevertheless, crops have been growing and developing rapidly during the last couple of weeks of warm weather.

Most wheat crops had a good T0 fungicide, which included a triazole component. Decisions on T1 fungicides will depend on weather conditions in the run up to leaf 3 emergence and forecast conditions shortly after.

Strobilurins are likely to feature at T1, especially on rusty wheats, second wheats and milling varieties. UAP trials since 2000 have shown that strobilurins improve utilisation of nitrogen, thereby increasing yield and grain protein.

Drier weather during March has allowed plenty of field work to be completed.  Most winter barley and oilseed rape crops will be due their final nitrogen top dressing towards the end of the month, although the timing on oilseed rape will depend on crop height, unless applying a later application of liquid.

Spring barley has generally been drilled into very good seed-beds, although some of the later-ploughed, heavier soils need to dry a bit more.  Pre-emergence herbicides are being applied to spring barley crops where grassweeds are an issue.

Winter barley crops are being sprayed with T0 fungicides and early plant growth regulator applications. There is plenty of mildew, net blotch and rhynchosporium visible and levels need suppressing to maximise tiller retention and drive yield. 

Oilseed rape is trying to move rapidly through stem extension, although some cold nights and daytime winds seem to be holding crops back a bit.  Once stem extension gets underway again most crops will be sprayed with a PGR fungicide. 

The last couple of weeks improved weather has allowed some drilling of spring barley and beans to be completed as well as picking off a bit of Atlantis/Pacifica (iodosulfuron + mesosulfuron) spraying. 

The autumn residuals have generally worked very well, but tidying up of surviving grassweeds is likely to continue over the next few weeks, assuming conditions remain mild and soil temperatures carry on rising.  

Soils have certainly warmed enough to mineralise nitrogen and the first SMN results indicate that levels are more akin to average in Eastern counties.  Further results are due this week and then we will be able to build a more comprehensive picture of SMN levels. 

Top dressing on oilseed rape started last week and will continue this week before moving onto barley and second wheats.  All first dressings will be nitrogen + sulphur.