21 November 2006
Extended drilling and mild conditions mean that wheat fields range from well-tillered lush crops to only just emerged. This, coupled with good residual herbicide activity, has complicated grassweed control decisions.
Earlier-drilled wheats have had Atlantis (iodosulfuron + mesosulfuron) applied following pre-emergence Liberator (flufenacet + diflufenican) or Crystal (flufenacet + pendimethalin). Despite the occasional frost recently, the plan is to continue spraying Atlantis on blackgrass fields where it has fully emerged as long as conditions remain favourable.
Fields with mixed grassweed populations (including blackgrass, ryegrass and brome) have had a pre-em and, where necessary, a post-em holding spray based on isoproturon or chlorotoluron.
If this doesn’t achieve sufficient levels of control, these fields will receive spring Atlantis or Pacifica once conditions are conducive. We know from trials and field experience last year that active growth of weeds is vital for good control from these products.
Any later-drilled wheats will receive a post-em herbicide, if they haven’t already had a pre-em treatment, with a view to following up with Atlantis or Pacifica in the spring once grassweeds are fully emerged.
Aphids are still active in some places and where seed treatments have now run out of steam (after 6-10 weeks depending on seed rate and drilling date) an aphicide will be added to the autumn Atlantis.
Most oilseed rape fields with grassweed problems have had their residual grassweed herbicide. The addition of a contact graminicide can boost control by 5-10%, especially on larger weeds.
The herbicide treatment has generally been coupled with a fungicide for phoma control. Even where crops received an early phoma fungicide in October, reinfection has occurred 3-5 weeks later in high pressure situations.
Wet and mild conditions will continue to favour disease development. Fungicide treatments in November have been based on flusilazole or Prosaro (prothioconazole + flusilazole) where the best and most persistent activity is required.
Insecticide treatment has been necessary where cabbage stem flea beetle larvae have been found inside stems and petioles at threshold levels.
14 November 2006
All oilseed rape crops that received a phoma spray six weeks ago are being assessed for reinfection. A second spray will only be considered where reinfecton is found and the variety’s resistance is low.
Cabbage root fly can easily be found in some early drilled crops, this will not only lead to loss of smaller plants, but to secondary fungal infection of larger ones. This could become a more serious problem in the future as rotations get tighter.
Pre and peri-emergence herbicides have worked well in winter cereals. With very little blackgrass emerging, a follow-up spray is not required at present.
Where growers missed out on this part of the blackgrass programme, the residual has been tank mixed with Atlantis (iodosulfuron + mesosulfuron), and due to good growing conditions, appears to working well.
Having had blackgrass resistance to Atlantis already identified on one farm, Atlantis is being applied at the recommended rate 0.4 kg per hectare plus a residual partner.
Just to remind growers that according to the Pesticides Safety Directorate, it is illegal to use a rate of Atlantis lower than 0.4kg/ ha, as it is out of the statutory box. If anybody has done, then it will compromise their farm assurance.
Winged aphids may now be found in crops which had seed treated with Deter (clothianidin) or Secur (imidacloprid).
7 November 2006
The majority of winter wheat drilling is now up to date and tight behind sugar beet harvesters having gone in very well.
Early crops are tillering well and those who ignored seed rate advice have a lot of lush crops. Both these, and more even crops, have noticeable mildew in them, with Claire, Alchemy and Glasgow showing symptoms.
There is no need to treat at the moment and with the colder nights, the problem should be lessened considerably. Beware though; the inoculum could reappear in the spring.
The weather and drilling has meant that a lot of early spraying has not happened, so some recommendations are having to be changed as the weeds are past the optimum stage.
Aphids are still present, although migration will be slow in colder conditions.
Winter barley, particularly Pearl, is exhibiting net blotch, although other varieties are clean. Manganese deficiencies are showing up in the usual suspect areas and should be addressed sooner rather than later especially as there is a correlation with mildew.
Oil seed rapes are showing varying degrees of phoma with the HEAR varieties worst affected and a lot of treatments have gone on for this.
Slug activity, though slowing, is still with us and large rape plants are being skeletonised. Keep watching!
Thistles in rape and cleavers up to four inches tall are common in non-inverted, unsprayed crops. Colder weather means we are getting to a stage where Kerb (propyzamide)/ Carbetamex (carbetamide) products can be applied.
Winter beans are going in – try to get the seedbed as level as possible to facilitate spraying and ease combining.
Interesting forward cereal prices are creating some soul searching decisions for the coming year.
Watch out for more National Register of Sprayer Operators roadshows early in the New Year in continuance of the Voluntary Initiative theme.
30 October 2006
Fungicides applied for growth regulation in September and early October have worked well, however, crops sprayed early will need re-checking for new phoma lesions and a second fungicide will be required if threshold levels are reached in the first half of November.
It is still too warm for Kerb (propyzamide) and Carbetamex (carbetamide) to be applied, so two trips through the crop may be required.
Check the rooting depth of blackgrass. Kerb will be most effective where the blackgrass is rooting in the top 2–3 cm. If it is rooting deeper than this, then higher levels of control may be achieved with Carbetamex/ Crawler. With both herbicides, wait for soil temperatures to become cooler before application.
Slugs are very active in the damp, mild conditions and are still causing problems on large well established crops.
Aphids are increasing in numbers and a second aphicide will be required on any wheat crops which were treated two to three weeks ago.
Where an insecticidal seed treatment was used, this will offer protection for at least six weeks from drilling. This point is being reached on many early-drilled crops.
Where significant populations of blackgrass are likely to compete with the wheat crop, then Atlantis should be applied once the majority of the blackgrass is at the two leaf stage, but by mid-November.
Warm soil temperatures are more important than warm air temperatures for good Atlantis activity, so do not be put off by the first few frosts.
Mildew is present on most early drilled fields of Claire and Solstice, however no treatment is required.
Aim to have winter beans drilled or ploughed-in by mid-November. Remember that Kerb must be applied pre-emergence of winter beans. Simazine cannot be used after December 2007, so plan to use stocks before this date.
23 October 2006
With wheat crops emerged, thoughts are now turning to post-emergence herbicides and insecticides.
Generally, conditions have been ideal for residual herbicide activity with good quality seedbeds and moist soils. Later drilled crops are showing the benefit of the extra pre-drilling glyphosate spray used to further reduce grass weeds populations.
Where pre-emergence sprays have been missed, prioritise the worst fields and spray at peri- or post-emergence. Liberator + IPU/CTU has given good results in trials and can be mixed with an insecticide for aphid control. Remember not to apply Atlantis until 4-6 weeks after IPU or CTU to avoid antagonism.
Atlantis should be applied to black-grass that is small and actively growing. Tank-mixing with a residual partner will help to control any black-grass that germinates after application. For this reason, autumn applications are preferable, but be guided by conditions rather than calendar date.
Oilseed rape growth stages are more advanced than we like to see them. Crops which have already had one dose of metconazole for growth regulation will benefit from another in the next week. Most will need a split dose fungicide programme due to early phoma infection and continuing mild conditions, with the second treatment hopefully coinciding with grass weed control.
Soil temperatures are still too high for herbicides carbetamide and propyzamide and best results will come from applications in November and December. When frosts arrive, the large oilseed rape canopies will open up, aiding weed control. Keeping water volumes up to a minimum of 200l/ha will help residual herbicides reach the soil.
16 October 2006
They say it never rains but it pours, and nothing could have been so right for the end of September.
Downpours brought a sudden end to drilling, leaving people exasperated as most had only three to four days left, except those who drill winter wheat after potatoes and sugar beet.
With a return to dry whether the drilling of second wheats has commenced, which brings them to the optimum timing for drilling?
Forward oilseed rape crops have, or are about to be, treated with a tank mix of fungicide with growth regulatory effects plus fungicide that offers phoma control.
The pre emergence herbicides on rape have worked well, considering how dry it was at time of application. Crops that did not receive a graminicide, have, or are about to receive a tank mix of residual plus contact.
It is better to get the residual on when the grass weeds are small, and have not become too deep rooted, as occurs with later applications. Rape crops should also be inspected for aphids, as these transmit Beet Western Yellow virus, and all crops grown for seed should be sprayed to prevent infection.
Some winter wheat crops look like they should do in March. Due to the warm soil temperatures and rapid growth, those that have had a pre-emergence herbicide are exhibiting some herbicide uptake.
Due to well consolidated seedbeds, and rapid growth, slugs have yet to be considered a problem. Small areas of grazing have been seen, but only where seedbeds are knotty.
Yellow rust can be easily found in Robigus, as can mildew on other varieties of wheat. Net Blotch can also be easily seen on Pearl winter barley. Treatment is not considered, as growth will cease as day length decreases.
Blackgrass is emerging rapidly, and crops that have not had a pre-peri emergence herbicide, will receive a contact plus residual during the next three weeks.
10 October 2006
Weather though changeable has meant drilling has continued well and crops are emerging fast. Pre-em herbicides are turning into peri-emerged as drilling is taking precedence over spraying. Insecticide seed dressings have taken the pressure off aphid control but with early aphids in the crops now aphicides must not be forgotten where no dressings have been applied.
Blackgrass is emerging fast proving low dormancy this year and planned treatments are reflecting this. Care must be taken with tank-mixing treatments in rapidly growing crops particularly where EC formulations are being used. This especially applies to barley as last year had crop scorch issues with non-hardened crops.
With a lot of min-till drillings this year and the recent wet, slugs are proving to quite a nuisance in many areas. Heavy rains in some areas have “melted “ the cheaper formulations so a constant watch is needed particularly where there is a lot of trash on the surface.
Early oilseed rape drillings are now at five to six leaves and some are in need of slowing down if they are not to be too forward over winter. There is also phoma appearing and it looks likely that two treatments will be needed this autumn in these crops. There is also a threat of BYWV as a lot of aphids are being found on uncontrolled volunteer cereals.
Low sugars (15-17%) are no surprise in sugar beet being lifted now. Some quotas are not going to be fulfilled.
ELS anniversaries are showing up that some growers are not aware that they have entered or were entered for management plans. Failure to have them done if there is an inspection could result in a loss of payment. Check if applied for as they are not easily done in a day!
3 October 2006
Winter Oilseed Rape
Early drilled and autocast crops are probably as forward as I have seen for the end of September.
On these very forward crops it may soon be worth considering applying a triazole fungicide for growth regulation. The greatest growth regulatory effect will be achieved if the fungicide is applied while the crop is still actively growing and before it becomes too large.
Phoma is just starting to make an appearance in forward crops (though not yet at threshold), so check crops carefully and spray as soon as 10% of plants are infected in susceptible varieties (e.g. Winner, Lioness) or 20% plants infected in a resistant variety (e.g. Astrid, Castille).
At the other end of the scale, later drilled rape crops are at the cotyledons to one true leaf stage and are showing high levels of downy mildew. This should not be confused with Phoma and does not requite treatment.
Later drilled crops are still at risk of slug damage and although they are generally establishing well, slugs are causing problems in some areas, so keep monitoring and be prepared to treat as required.
Turnip sawfly larvae (which look like caterpillars) are stripping leaves off forward crops in the south of East Anglia. This is an unexpected third generation, which has appeared due to the warm September. Sprays applied for cabbage stem flea beetle will give good control.
Early-drilled crops of wheat have emerged quickly and are at the 2-3 leaf stage. Slugs are active and crops need to be monitored until they have three leaves. Deter (clothianidin) seems to be reducing grain hollowing, however, it does not protect from slug damage once the crop has emerged.
Gout fly numbers appear to be low, however, aphid numbers are high, so where Deter has not been used, a pyrethroid will be required for Barley Yellow Dwarf Virus control.
26 September 2006
Good conditions for drilling wheat during September have resulted in crops going into good quality seedbeds and emerging quickly.
Deter (clothianidin) seed treatment will provide some protection against grain hollowing from slugs and more persistent activity against aphids. Nevertheless, once crops emerge, be vigilant for leaf grazing by slugs and monitor for aphids and gout fly eggs – risk of both pests is high at this stage.
Low blackgrass dormancy has resulted in rapid germination and emergence. Ensure blackgrass/ brome/ ryegrass fields are targeted with an effective pre- or peri-emergence residual herbicide.
Good seedbeds and recent rainfall provide ideal conditions for residual herbicides. Where wheat fields are yet to be drilled take the opportunity to spray-off grass and broad-leaved weeds with glyphosate beforehand.
Oilseed rape is growing rapidly in warm, moist conditions with earliest crops at 7-8 leaf stage. These crops will benefit from a fungicide with growth regulatory activity if conditions continue to encourage rapid development.
Blackgrass is also growing rapidly in rape crops, so consider at least holding grassweeds with a contact graminicide. Otherwise grassweed plants will be well-tillered and competing with the crop by the time soils have cooled sufficiently to apply carbetamide or propyzamide.
Continue to monitor for slugs in OSR – the crop remains very vulnerable up to the four leaf stage and even beyond if slug pressure is high. Use a pasta-based pellet for greater persistence in wet conditions and use an appropriate rate to apply a minimum 40 baiting points per square metre.
Check for flea beetle and aphid (aphids are vectors for Beet Western Yellows Virus) and spray with a pyrethroid insecticide where the pests are found in crops.
Minimum tillage/ direct drilled OSR crops with high levels of straw in the seedbed and low nitrogen residues will benefit from 30kg/ha N. Early-drilled forward crops will not need any additional encouragement with nitrogen!
Low P and/ or K soils will benefit from early applications to aid crop establishment.
19 September 2006
Early drilled rape is at the three to four leaf stage, and all conventionally established rape has been treated with a pre-emergence herbicide containing metazochlor plus trifluralin, depending on weed spectrum.
They are now about to receive a graminicide in order to control the fast emerging volunteer cereals and grass weeds. Application was delayed last week due to high temperatures, and winds that put the crop and volunteers under moisture stress.
With rain occurring mid-week, the situation has altered. Late drilled rape crops are emerging within seven days of drilling.
Due to the return of moisture, the threat of slugs also returns, even to crops that have been treated. Traps comprising of chicken bran have been set, even in fields that appear to have escaped damage.
Drilling of first wheat on fields where blackgrasss is not a problem is well under way, into good seed beds. Adequate moisture and high soil temperatures mean emergence has been rapid.
Due to these conditions care should be taken on choice and application of herbicides, if any, as the crops are very soft and tender and can be easily damaged. Also with high soil temperatures residual herbicides can be broken down rapidly and therefore be less effective.
Winter wheat crops that have emerged and were not treated with Deter (clothianidin) are receiving a pyretheroid insecticide tank mixed with manganese, as winged aphids can easily be found in volunteer cereals as well as the grass margins around fields.
From test results black grass dormancy is low this year, so fields where target site and enhanced metabolism resistance is known, are being allowed to green up, before spraying-off with glyphosate.
These will be drilled towards the end of September, when hopefully soil temperatures will have dropped so that we can get maximum effect from residual herbicides.
12 September 2006
After a frustrating August, the cereal harvest has finally finished with yields, in this part of the world, generally very good. Wheats were averaging 10-11.8t/ha on the heavier soils and a respectable 10t/ha on some of the lighter soils.
One crop of Glasgow in the area yielded 13.5t/ha, which, given the scoring of four for lodging untreated, showed the benefit of robust treatments of growth regulators. This, with the ever increasing higher yielding varieties, is an area that will need more serious thought in the future.
The wet second half of August took the edge off what was promising to be one of the best for years and although the yields were still up, the quality was affected with a lot of sprouted grains.
Thoughts turn to oilseed rape drilling and some of the earlier drilled crops are beginning to romp away despite 75mm (3 inches) of rain in four days. Unrolled crops have had to be slug baited as the wet has brought several grey slugs to the surface. Vigilance will be necessary.
Volunteer cereals and grasses must be taken out early, with special care being given to the new Pesticide Safety Directorate’s guidelines on ACCase inhibiting post-emergence graminicides.
Because of the weather some pre-em herbicides were not applied so check whether they can be used post-em.
Pulses yields were disappointing and some winter beans are still to be harvested. Human consumption spring beans suffered from the drought and produced small seeds and despite treatment had more than usual bruchid beetle damage.
With such a hit and miss recommendation, a better understanding of this pest and a new product would be very useful if we want quality beans.
Blackgrass dormancy should be low this autumn so control strategies need to reflect this.
5 September 2006
Early drilled or autocast crops of winter oilseed rape are growing rapidly and have three or more true leaves.
Volunteer cereals are also emerging and growing rapidly and need to be controlled before they begin to compete with the crop.
Other grass weeds are likely to be slower to emerge, so aim to apply a low rate of graminicide for volunteer cereals now and spray again later with a more robust product for blackgrass, ryegrass and brome.
So far there has been very little flea beetle damage, however, a return to drier milder weather may increase flea beetle activity, so later emerging crops will still need monitoring as they establish.
Slugs are still very active and all crops need to be monitored on a regular basis, treating with slug pellets if required.
Oilseed rape drilled into moist seedbeds will establish quickly, so there is still time to drill crops successfully up to mid-September. Seed rates should be a little higher on later drillings and autumn applied nitrogen is more likely to be beneficial.
Some farms will be considering early drilling winter wheat soon. Aim to establish 125 plants/m2 for early September and 150 plants/m2 for mid-September drillings.
Thousand seed weights vary considerably this year, so remember to adjust seed rates accordingly. Also take into account seedbed conditions and slug risk.
If slugs are very active, then consider a pre-bait of slug pellets a couple of days prior to drilling. Unless land is likely to cap, rolling after drilling will be essential to reduce the risk of slug damage.
The showery weather has encouraged grass weeds to emerge in stale seedbeds. Delay drilling in the most difficult grass weed fields as long as possible and then spray off with glyphosate before cultivating or drilling.