Crop Watch – South autumn/winter 2005

22 November 2005

Tod Hunnisett – Chichester Crop Consultancy

The recent drop in temperature has stopped the rampant autumn growth in its tracks. It has also hardened off the soft growth and coupled with the settled weather, many crops are getting their main autumn herbicide.

But, many fields are still wet underfoot and if they are waterlogged they should not be sprayed. The general rule is that if they squelch when you walk across them, don’t spray; especially not with isoproturon or chlorotoluron. For a start it simply won’t work; and secondly the risk of contaminating watercourses is too high.

The frosts have also done a good job on powdery mildew – it’s a very cheap fungicide!

Oilseed rape, especially big crops, has suffered some leaf damage caused by the cold weather but no real harm has been done. Now soil temperatures are dropping we can think about using propyzamide or carbetamide for difficult grassweed control but there is still no great hurry.

Phoma levels exploded before the cold weather set in, but with nearly all crops getting a specific phoma fungicide I don’t see many crops needing re-spraying before the spring, especially given the size of some of the plants.

Winter beans are now all in. I have yet to see any emerged and everything will be getting pre-emergence simazine. Fields with a known cleaver problem will have pendimethalin added.

If we do go into a long spell of cold weather, crops that were destined to have Atlantis (iodosulfuron + mesosulfuron) will wait until the spring. It definitely works better under good growing conditions and, as we are tending to use it in challenging situations, we must try and get the best out of it.

One last thing – although it seems ages away – have a good Christmas!


15 November 2005

James Short – Hutchinsons

The mild weather has encouraged a flush of grass and broadleaved weeds in cereal crops. Where spraying has been delayed, use residual herbicides with contact activity.

Aphids continue to be high risk – monitor and apply an aphicide if necessary.

Mildew and brown rust are easily found in susceptible varieties. Autumn fungicide use is usually not warranted unless active mildew is found in susceptible barley and wheat varieties grown on light soils. Frosts and cold weather can be a very effective fungicide!

Oilseed rape crops not treated for phoma should be monitored closely. A second fungicide application may be required where the disease is again active in previously sprayed crops.

With colder temperatures and moist soils, the optimum time for controlling grass weeds with propyzamide or carbetamide is now approaching. It is essential to follow best use guidelines with these products for consistent weed control.

Contact herbicides for Charlock and Cranesbill control need to be applied when the rape crop is fully waxed and has five leaves or more. Careful application timing will prevent crop damage and poor results.


8 November 2005

Steve Cook – Hampshire Arable Systems

Winter wheat crops are still growing fast and now tillering well. Slugs have reappeared in many crops since significant rains have come.

Rain has improved the activity of pre-emergence herbicides such as Crystal (flufenacet + pendimethalin) and now small blackgrass plants are dying. In these cases it is too early for Atlantis (iodosulfuron + mesosulfuron).

Where blackgrass is already tillering then Atlantis will be applied at the next opportunity. Weed control generally has been very good and feared damage to soft crops has been minimal.

Secur dressed crops will need an aphicide as rapid growth will have diluted the insecticide and continuing mild conditions will allow further movement of aphids into the crops and a high risk of Barley Yellow Dwarf Virus infections.

Mildew is causing some dramatic yellowing in the most forward wheat crops of susceptible varieties, but autumn infections rarely lead to any yield loss. This should serve as a warning for the spring.

Oilseed rape crops are now infected with Phoma and so fungicides have recently been applied or will be at the earliest opportunity. Many crops are very forward but this could be an advantage this year. Pigeons are already attacking thinner crops and there does not seem to be as much of their alternative food sources around, so rape crops could be at higher risk this season.

Where sowing of winter beans has been possible emergence has been rapid from the warm soils. Beans are emerging from 12cm (5”) in 7 to 10 days. This does cause problems if pre-emergence only herbicides have been recommended, and opportunities to spray have been limited.


31 October 2005

Neil Potts – Matford Arable Systems

Most wheats are now drilled, with just a few late crops after maize and beet still to be drilled.

Some early sown crops have severe brome and ryegrass problems but early applications of Atlantis (iodosulfuron + mesosulfuron) appear to be coping well.

Septoria is not yet in evidence but after recent prolonged and heavy rain (over 10% of our annual rainfall in a week) combined with very mild conditions we can expect septoria to be with us fairly soon. Unless we have a cold dry spell it will stay with us until we start control programmes in the spring.

Wild oats are showing little or no dormancy this year and there have been some massive flushes already, necessitating early control.

The current mild weather means we will have to be particularly vigilant about aphids and the constant threat of BYDV in this part of the country.

The winter barley acreage has enjoyed a minor revival this year, buoyed up by high straw values. Crops are emerging well along with a raft of annual grass and broad-leaved weeds, which will need controlling early if crops are to be kept clean and costs kept under control.

Most oilseed rape has established well and the weed control programme is by and large complete. There is little sign of phoma at the moment but the recent wet weather could change that. Most crops are destined to receive a fungicide about now.

The winter oat acreage has increased this year on the back of some good contract prices for harvest ’06. The crops are looking good with many now receiving a treatment of Lexus Millennium (flupyrsulfuron + thifensulfuron) + aphicide to try to control grass weeds where they represent a threat. With high nitrogen prices we cannot afford a carpet of meadow grass in the bottom of crops, acting as a sponge for nitrogen applications next spring.


25 October 2005

Tod Hunnisett – Chichester Crop Consultancy

Oilseed rape crops have continued to grow vigorously in the mild conditions with many past the nine true leaf stage, which is the latest timing for the application of Aramo (tepraloxydim).

Some crops will receive a growth regulator type fungicide this autumn, probably tebuconazole  or metconazole. Phoma levels have varied from zero to well above threshold. Expert seems to be the cleanest variety with Winner probably the worst, but phoma incidence seems to be much more associated with the crop’s proximity to another source of infection, either geographically or rotationally. Where crops are at threshold (10% plants infected) a specific product with curative activity on phoma (e.g.: flusilasole or difenoconazole) will be used. This is particularly important on small, backward crops.

Similarly, wheats are growing equally quickly. Many crops are well into tillering and ready for autumn herbicides. Be aware high rates of active ingredients or complicated tank-mixes can lead to crop effect if sprayed onto crops not yet hardened by cold weather. However, autumn crop effect very rarely manifests itself as a final yield reduction.

Slugs have continued to be a problem. The mild nights have been perfect for a new generation of juveniles and many well established crops are losing top growth due to grazing. The move away from power-harrowing in non-ploughed situations seems to be allowing a greater survival of adult slugs through the cultivation process. Any crops in high risk situations should still be monitored even if they appear to have established well.

Winter beans will go in any time now as soon as the weather permits. An increasing area is being drilled into non-ploughed ground. This works well provided the seedbeds have been cleaned up with glyphosate and the seed rates are kept sensible; around 20-25 seeds per sq m is a reasonable figure. Also keep them plenty deep enough – 10cm plus – well out of the zone of any simazine which, while we can still use it, is still the best value residual herbicide we’ve got for beans.


18 October 2005

James Short – Hutchinsons

Recent rain has encouraged a flush of grass weeds to emerge in early drilled cereal crops. Plans need to be revised where spring applied Atlantis (mesosulfuron-methyl + iodosulfuron-methyl-sodium) was intended in these situations.

Resistance is a real issue and trials have consistently shown that the best results are achieved when the majority of blackgrass is sprayed at three leaves. Be warned – get the timing wrong and the consequences can be long lasting and expensive!

Aphids and gout fly eggs are readily found in cereal crops at 2-3 leaves. Apply a quality pyrethroid and be prepared for a second application due to the mild weather forecast.

Secur/Deter seed dressings will protect the crop from aphid attack but should not be relied upon for season long control in early drilled crops. Slugs are proving to be a real problem especially after oilseed rape – apply pellets as soon as slugs are detected.

Forward crops of oilseed rape are now at 6-8 leaves. The first signs of phoma leaf spot are showing – spray as soon as the lesions are visible.

Phoma is the key oilseed rape disease in the south and can decimate yields if not correctly treated. Timing and product choice are essential to maximise yields in rape/wheat rotations. Very forward crops will benefit from canopy manipulation.


11 October 2005

Steve Cook – Hampshire Arable Systems

Oilseed rape has generally established very well despite some slug problems. There are now very occasional phoma lesions but nowhere near threshold.

We do not want to go to go with a fungicide this early, unless threshold is reached, as it is likely that a second autumn fungicide would be needed.

Soils are still too dry to consider Kerb (propyzamide) or Carbetamex (carbetamide) treatments for bad blackgrass areas. There is a little downy mildew present on most crops but with rapid growth this of no consequence.

Winter cereal sowing is now completed on most farms. A few second or first wheat crops after maize are still to be drilled, but soil conditions remain good so I am confident that this will be completed very soon.

Early September sown crops are already tillering. Most other crops are at 1-2 leaf stage and are at the perfect stage for early post-emergence residual herbicides. Grass weed emergence has been slow due to dry conditions but I expect there to be flush as soon as there is significant rainfall.

We are advising all farms too take extra care to avoid spillages and do whatever they can to prevent pesticides entering watercourses.

Seedbeds have been good and firm and with seed place at 1.5inches (30mm); we have kept slug damage to a minimum, with hardly any seed hollowing. Some surface grazing has been treated, but there has been no crop loss yet!

Winter beans should not be sown until 20 October. Earlier sowing could lead to the crop getting too far forward before the winter. Those who will/cannot wait should sow deeper to delay emergence.


4 October 2005

Neil Potts – Matford Arable Systems

Oilseed rape crops are now all drilled up. Early planted crops are well established but the later drilled ones are struggling with slug damage being fairly universal.

Early drilled crops will require a graminicde for cereal volunteers shortly if not already applied.

Winter wheat drilling is in full swing with the earliest sown crops already at the two leaf stage. These will require an aphicide urgently if not treated with Secur or Deter seed treatments.

Brome grasses are showing very low levels of dormancy this year, with some massive chits having already occurred. With the open autumn weather this is giving an ideal opportunity to ‘stale seedbed-out’ this troublesome grass weed.

Winter barley drilling is yet to start but winter oat sowing is underway. There appears to be renewed interest in this crop this season with some reasonable contracts available for 2006 harvested crops.

The maize harvest is well underway with yields generally high but until the dry matter analysis comes back we won’t know for certain. I suspect some crops have been harvested too soon which will give low dry matter content without maximum starch yield. I hope I am proved wrong on this count.


27 September 2005

Tod Hunnisett – Chichester Crop Consultancy

Oilseed rape has been drilled with most crops up and away. Slugs have been a problem with a few places needing re-drilling. One third rate mini–slug pellets was enough to make the difference between saving and losing the crop in some instances this year.

Most crops have had a pre or early post emergence spray, usually metazachlor based, with a graminicide if volunteers are more than two leaves.

Wheats have gone in under text book conditions with many fields getting timely applications of glyphosate onto well greened–up stale seedbeds.

Pre-baiting with slug pellets has resulted in a very high kill of slugs, especially after oilseed rape. Where no action has been taken, at the very least trapping or monitoring should take place because all the indications are that populations are very high again this year.

Pre–emergence grassweed sprays are going on straight after drilling and these include everything from trifluralin (cheap) to Crystal (flufenacet + pendimethalin) (reliable). Uranus (linuron + trifluralin) must go on pre – emergence.

Pay attention to the drilling depth when using anything with pendimethalin in it – a minimum of 35mm settled soil above the seed is needed.

Where seed has not been insecticide treated aphids can come in very quickly so be prepared to go in with a pyrethroid at one leaf if aphids are found.


20 September 2005

James Short – Hutchinsons

Good weather has encouraged an early start to wheat drilling with Solstice, Robigus and Cordiale proving to be popular varieties following some exceptional yields this harvest.

Seed rates should be specific to drilling date, seedbed conditions and variety. It is advisable to delay drilling fields with blackgrass, ryegrass and brome until late September / early October.

Second wheats continue to decline in acreage – Latitude (silthiofam) seed dressing is recommended unless planting is delayed until mid October.

Do not be tempted to avoid using pre-em or early post-em residual herbicides in fields with difficult grass weed populations. Managing herbicide resistance is a key agronomic challenge. Get it wrong and the consequences can be long lasting and expensive.

Be vigilant for slugs especially after oilseed rape. Consolidated seedbeds and good straw incorporation will reduce reliance on slug pellets.

Early drilled oilseed rape is now at 3-4 leaves. Volunteer cereals can be controlled with a low dose herbicide, with two applications probably necessary in non- plough situations. Watch for early Cabbage Stem Flea Beetle damage and the ever-present slugs.


13 September 2005

Steve Cook – Hampshire Arable Systems

Oilseed rape has established very quickly with early sown crops already at the three true leaf stage.

Pests have been minimal as crops came through the ground rapidly and evenly, if anything crops could be too thick despite reduced seed rates.

There are occasional slug or flea beetle problems on broadcast crops where establishment has been more variable and we can not afford to lose any plants.

Some minimum tilled crops may need volunteer removal already, but in most cases volunteers germinated before sowing and were sprayed off effectively pre-sowing. There is a little downy mildew present, but with rapid growth this of no consequence.

Winter cereal sowing is under way on most farms, with first wheats taking priority over winter barley. Claire will be the first variety sown, followed closely by Solstice and Malacca, with Einstein and Robigus following at the end of the month.

Soil moisture is ideal for easy seedbed preparation with the minimum of effort, so do not over work soils. Subsoil structure is generally good and tramlines are only compacted in top four inches and there is generally no need for deep cultivations.

Work only as shallow as you need to prepare enough tilth and even where ploughing you may not need to work more than five to six inches. If seedbeds are firm after sowing then there is no need to roll. Any pass saved will save expensive diesel but must not compromise establishment.

Pre-emergence sprays are planned and in stock so they can go on straight after drilling, as crops and weeds are likely to emerge rapidly from the warm seedbeds.


6 September 2005

Neil Potts – Matford Arable Systems

Harvest results have been a bit variable but on the whole good. Oilseed rape yielded very well with most achieving yields of about 4.5 t/ha.

Winter barleys on the whole performed well but yield was dependant on a robust fungicide programme. Where the programme was kept to a one spray approach yields were cut by 1.25 to 2.0 t/ha.

Winter oats have yielded well with yields between 7.5 and 11.3 t/ha.

Winter wheats have been a bit more variable but again the key to success has been a good fungicide programme, with the T0 timing appearing to have played a crucial role in building yield this year.

A simple T1 and T2 approach to disease control has given some disappointing results this year with yields as low as 4.7 t/ha whereas a full 4 spray programme has given consistent yields between 9.4 and 12.5 t/ha.

Spring crops have done well too, with spring barley yields at or very close to 7.5 t/ha. Forage Maize is having a very good year. Crops are looking like they will be heavy and that harvest will be quite early, even on marginal sites.

Winter oilseed rape is in the process of being drilled on most farms as I write and wheat and oat plantings will commence in earnest in the next week to ten days.


30 August 2005

Tod Hunnisett – Chichester Crop Consultancy

Harvest has been a mixed bag with some yield potential lost due to the drought pre – harvest but some crops which held on have yielded spectacularly.

Star performers this year have been Gladiator, Robigus and good old reliable Claire. I still can’t get Hereward to yield however hard I try. Ergot has been a problem this year and XI 19 seems to be the worst variety; any comment on varietal susceptibility would be most welcome.

Oilseed rape yielded a good average this year with no real disasters and some extremely good yields on the south coast. Winner held its own but Expert, Castille and Lioness were generally better performers overall.

The wet weather which hampered harvest, stimulated a major emergence of weed seedlings, particularly ryegrass.

The opportunity to control these with glyphosate must be taken before the crop is drilled.

If they are only going to have one application of glyphosate, this ideally needs to be as close as possible to the time of drilling but depending on which product is used it must be on long enough to get into the plant. In most cases this would be 24 – 48 hrs for annual weeds.

This is particularly important if there has been an emergence of broadleaved weeds in ground destined for non–ploughed oil seed rape. Trying to control large BLW post emergence in small OSR is a hiding to nothing.

Planning for pre–emergence sprays in cereals should be taking place now. The value of the pre–emergence herbicide in bad grass weed situations cannot be overstated.


23 August 2005

James Short – Hutchinsons

Changeable weather has delayed wheat harvest in the south-east, and linseed and bean crops remain to be harvested. Linseed desiccation is essential in weedy or uneven ripening crops to prevent difficult combining.

Autumn oilseed rape drilling is progressing well, with a wide range of establishment systems used on farm.

Consistent high yields of oilseed rape rely on a good root system – subsoiling is not always necessary but deep tine cultivation will allow full yield potential to be realised. With commercial farm yields of 5t/ha now being achieved it is essential to fine tune all aspects of oilseed rape agronomy.

Weed control programmes need to be planned before the crop is drilled. Trifluralin and Centium (clomazone) can only be applied pre-emergence. It is important to use Centium if hedge mustard is likely to be a problem. Avoid metazachlor applications pre-emergence if heavy rain is forecast to prevent crop damage.

Herbicide options in autocast crops usually rely on post emergence products. Watch for cabbage stem flea beetle activity in emerging rape crops and the ubiquitous slug. Good, consolidated seedbeds will limit the damage potential of both pests. Seed rates should aim to establish 60 plants/sq m for conventional varieties.

With diesel and machinery costs continuing to escalate, stale seed bed techniques are invaluable to reduce overall cultivation costs. Timely applications of glyphosate herbicide and an appropriate adjuvant will control grassweeds, cereal and oilseed rape volunteers for under £5.00/ha.

The farm sprayer should not be overlooked as a very effective cultivator.

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