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Wendy Fearon

Rain Driving Growth in Spring Cereals


The mix of sunshine and rain over the last couple of weeks has provided a period of good growth in all crops, but with this comes a ramping up of weed and disease activity. The heavy showers in recent days have encouraged even germination of weed populations in all spring cereal crops, and if not already sprayed for these, should be done so as a priority in coming days, as performance will fall off rapidly when the weeds become larger and the crop canopy closes, shading out the weeds underneath. As a result of a near ideal balance of heat and rain since planting, all spring crops are now well established and well into the tillering growth stage. Most are clean and canopy cover is consistent right across fields.

Chlorothalonil revocation update

Following the announcement of its revocation earlier in the year, the use up period for chlorothalonil containing products has been announced. Products may be sold up to 20th November this year, and growers will have to the 20th May 2020 to use or dispose of stock. Whilst the fact growers will have the active for much of next season is better news than might have been expected, longer term its loss will impact significantly on crop protection programmes in terms of efficacy and resistance management.

Disease Control

Spring Barley

At the moment crops look pretty clean, so in most cases the lower end of the dose range will suffice, but with disease risk closely linked to heat and moisture, decisions on rates are the ultimate in-field decision and should be tailored to the disease pressure in each field.

Even where crops are considered to be clean, controlling Rhyncho early is much more effective than leaving it until it is seen. Once infection has come in, any eradicant treatment has limited efficacy, and the infection will stress the crop, increasing the risk of Ramularia infection. The T1 application should be applied at the end of tillering to the start of stem extension, GS24-31.

The T2 timing should be aimed to continue control of Rhyncho and Net Blotch, but also timed to maximise control of Ramularia. Flowering and senescence are major triggers of symptoms, but other stresses also play a part including bursts of sunshine, diurnal temperature fluctuations, and the presence of other foliar diseases. This spray needs to be on ahead of Ramularia symptoms appearing on final leaves one and two and persist for long enough to keep the crop green well in to grain fill. The best compromise timing for this is booting to very early ear emergence, GS41-49.

Options for T1 are based around core triazoles such as prothio, epoxi and cyproconazole. Prothioconazole remains the strongest performing triazole but epoxiconazole mixes are equally effective options, ensuring the various strains of disease are exposed to as many different actives throughout the programme as possible. Strobilurins improve the performance of the triazole partner, improving Rhyncho, Net Blotch and Rust activity. SDHIs will also give very good broad spectrum disease control, but factoring in cost effectiveness, are a better fit at the more responsive T2 timing.

Spring Wheat

The young spring wheat plant isn’t subjected to the same disease burden as the overwintered winter wheat plant, therefore a two-spray programme usually suffices, with the T1 applied at 1st-2nd node, GS31-31, and the T2 applied at some point during booting, GS41-49. Whilst a large proportion of these crops are harvested as whole-crop earlier than the conventional combined crop, the feed quality of the harvested crop is very dependant on maximising grain-fill, therefore product choices and rates are similar to those of the winter crop, with significant yield responses to a proper programme.

Spring Oats

Powdery Mildew and Crown Rust are the most damaging diseases in this crop. OPUS TEAM & COMET in mixture is the strongest combination in terms of controlling both these diseases and therefore yield improvement. Fenpropimorph (an active in OPUS TEAM) is extremely effective in terms of Powdery Mildew control, and the addition of COMET (a strobilurin) gives unrivalled Crown Rust control.

A single application of fungicide should be applied at 1st – 2nd node, (GS31-32) eradicating any Mildew and Rust already present, and providing persistency right through to harvest.

Lodging Control

Spring Barley

Application of SELON at early tillering will have increased tiller and ear numbers and therefore yield potential, but will not have given any reliable strengthening of the straw. Stems that extend rapidly during the stem elongation phase (as is likely to happen this season because of late planting, high temperatures and soil moisture at present) are more likely to be weaker and so there is a greater risk of lodging especially where the crop is being pushed on with nitrogen. SONIS can be used but its cut-off in spring barley is 2nd node, GS32. CANOPY is a very useful alternative, safe to the crop and able to be used right up to and including full flag leaf, GS39. If this timing has past, CERONE can be applied up to before awns visible, GS45.

Spring Wheat

Because the application of SELON at mid to end of tillering (GS23-30) does give reliable later season lodging control in wheat, it is less likely than spring barley that spring wheat will need a growth regulator towards flag leaf unless the crop is particularly dense. If the crop still looks very rank and at risk of lodging as the stem elongates, apply CERONE or CANOPY, as the flag leaf is emerging.

Spring Oats

The optimum timing for treating spring oats is with SELON at 2nd node, GS32. However if the oats remain at risk of lodging, a follow up treatment of CANOPY can be applied during flag leaf emergence

Spring Crops Make Good Start

Spring Cereals

The much more pleasant milder night-time temperatures have seen a welcome burst of new growth in all crops. All spring crops have now brairded and without the more usual effects of waterlogging seen in other years, are looking very well. Although weeds are also emerging fast as a result of last weeks rain, be sure all are well through before spraying. Watch too the size of the annual meadow grass if this weed is also to be controlled – efficacy falls off rapidly once it begins to tiller.

A well timed application of SELON will encourage tiller numbers and tiller survival. This treatment must be well timed to maximise its effect, optimum timing for barley is from the 2 expanded leaf stage to beginning of tillering, GS12–21; in wheat the optimum timing is slightly later, 5 leaf to mid tillering, GS15-24. Many crops will have now passed through these growth stages. It is important to note that this season aphid numbers are the highest I have seen for a very long time and it would be advisable to apply an aphicide to control the spread of BYDV.

To minimise the effects of competition on the crop and optimise the level of weed control, herbicide application should be carried out once all weeds have emerged but are still small, and before they begin to compete with the crop for nutrients and light. Carrying out the weed control when they are at the 2-4 leaf stage is much more effective especially on difficult weeds such as fumitory and knotgrass, rather than delaying to coincide with the 1st fungicide application.

Broad leaved weeds resistant to particular groups of herbicides in NI is not a new problem – chickweed resistant to herbicides such as ALLY has been widespread throughout the province for some years. Sulfonyl urea (SU) herbicides such as metsulfuron have a single mode of activity, blocking the production in many BLW of a key enzyme, acetolactate synthase. Products that use this mode of activity are known as ALS inhibiting herbicides and include the SU chemistry. As well as chickweed, mayweed and poppy have also developed widespread ALS resistance. This particular resistance problem has been managed by including herbicides into the tank-mix with different modes of activity to maintain good weed control.

 

In NI spring cereals ZYPAR will give excellent control of a wide range of weeds that includes chickweed, fumitory, fat-hen, groundsel, brassica weeds, and cleavers. Its one relative weakness is redshank. Whilst it will control it to 6-leaf, it should be tank-mixed with another herbicide to ensure redshank right up to flowering is satisfactorily controlled. ALLY MAX and FOUNDATION are excellent tank-mix partners for this purpose.

 

Temporary nutrient issues

Manganese (Mn) deficiency is widespread in much of our local soil types, and particularly damaging to leaf vigour and yield if not treated. Continuous cereal cropping, ground recently limed and dry soils all increase the likelihood of deficiency. Symptoms begin with small pale green speckles appearing throughout the leaf and these will progress to turn brown unless treated. Barley is particularly susceptible to Mn deficiency. MAXMAN is a highly concentrated Mn(40%) in a completely soluble chelated nitrate formulation and also supplies 10.8% Nitrogen and 11.4% Sulphur

A young plant that is growing extremely rapidly is producing a huge amount of new plant tissue each day. This rapid growth is limited only by the availability of nutrients to synthesise biomass, dependant on soil fertility and the plant’s own root development to take up the nutrients. It is at this time therefore when nutrient deficiencies are most likely to appear and in doing so, suppress growth rates.

The application of a broad-spectrum trace-element mix along with key macronutrients during this time is a very useful and beneficial way to supplement the plant’s nutrient requirements during periods when availability does not meet demand, most likely to coincide with phases of rapid growth ie. during tillering and as stem extension begins. Application of a balanced and readily available source of macro & micronutrients that is topping up what is being made available from the soil at this key time will minimise the adverse effects of restricting nutrient availability. CEREAL HIGH N-supplies 250gm N, 125gm S, 38gm Mg, 93gm Mn, 45gm Cu and 15gm Zn per ha

FASTMIX MAGNESIUM PLUS is an alternative product specifically formulated to meet the increased micronutrient demand of cereals and other combinable crops with good yield potential. It is a quick acting foliar fertiliser containing high levels of magnesium and sulphur as well as manganese, zinc and boron, all in a water soluble form and readily available to the plant. It is very compatible in tank-mix with most pesticides and can be applied along with the T1 and T2 fungicide applications. Being a dry formulation, it should be fully dissolved in the tank first and other products added afterwards.

 

Winter Cereals

Winter cereals have greened up well and are now racing through the growth stages. Awns are now out on all winter barley crops with both T2 application and growth regulator applications complete. Winter wheat crops which have not yet received T2 should be treated as soon as possible along with the growth regulator if required.

Crops Going Through Growth Stages Rapidly

Winter Cereals

Winter cereal crops are moving rapidly through their growth stages. As a result of the predominantly dry April and better timed spray treatments than many other years, the wet weather diseases, Septoria and Rhyncho remain lower down the plants, well controlled by the T1 application. Dry weather diseases have been more problematic this year, with Net Blotch, mildew and Ramularia appearing in barley and Yellow Rust and Mildew in wheat.

As awns appear in barley and the flag leaf emerges in wheat, the T2 fungicide timing is fast approaching.

Properly protecting the top three leaves and ear at T2 is critical to yield and profit – foliar disease not controlled effectively at this time will hasten the senescence of these leaves during grain filling, and therefore impact adversely on yield and grain quality. This treatment will extend canopy duration therefore increasing the amount of starch produced for grain filling, and increase grain storage capacity leading to higher thousand grain weight (TGW).

Winter Barley

Correct timing of fungicide applications is critical to optimizing activity and product performance. The T2 treatment should be applied from flag leaf sheath extending, through booting to first awns visible, GS41-49. As well as protecting against Rhyncho, this treatment also needs to protect the plant against Ramularia, Brown Rust and Net Blotch through to the end of the season. Awns contribute equally to yield and it is important to keep them free of disease also.

For crops with good yield potential, the inclusion of SHDI along with triazole and multi-site is very much the norm now, ensuring persistency of the treatment right through to ripening. Best options include AYLORA or CONCORDE mixed with MOBIUS/MANTRA/RUBRIC and the multisite chlorothalonil. Good practice would be to use a different SHDI/triazole combination now to that already used at T1. Where a crop with lower yield potential discourages their use, non SDHI chemistry using triazole/strobilurin/morpholine mixes are also robust options eg OPUS-TEAM, MANTRA or MOBIUS. As a result of its resistance to triazoles and the SDHIs increasing, chlorothalonil should now be considered an essential component of all T2 treatments helping the control of Ramularia.

Winter Wheat

In wheat the T2 should be applied during the emergence of the flag leaf, GS37-39. Of all treatments, this flag leaf timing is the most responsive to yield and therefore products used should reflect this. Against a background of Septoria being present in all crops and significantly reduced kickback activity from core chemistry, the T2 timing is critical to ensure effective protectant performance.

Managing resistance and maintaining reliable disease control now means using a range of different actives over the course of the growing season

It is good practise to use different actives from within the same chemical group at the different spray timings. Where possible, use a different SDHI at T2 to that used at T1, and likewise use different triazoles over the course of the season to give the widest possible activity across the different strains of fungi of all diseases.

Because it provides multiple modes of activity acting preventatively on Septoria and has no known resistant strains to the disease, chlorothalonil should also be included in all well timed T2 programmes to provide some control of those strains now showing resistance to triazoles and even SDHIs. In crops susceptible to lodging a plant growth regulator should be applied at this time.

Docks & Chickweed Are Major Problem In Silage Swards

Docks

As thoughts turn to silage, treating dock-ridden leys with DOXSTAR PRO four weeks before cutting will significantly increase the amount of grass that ends up in the clamp and improve silage quality. Docks have much less feed value than grass and pull down dry matter.  FOREFRONT T is the most effective herbicide available to grassland farmers for the control of docks, ragwort, chickweed, thistles, dandelions, nettles and buttercups.  It is the longest lasting weed control product in grassland to date with a single well timed spray giving up to 18 months control so whilst it may appear expensive it really is good value for money. FOREFRONT T may only be applied to grazing ground.  However PASTUREPACK launched last season by Nufarm will cover a similar range of weeds and may be applied on silage ground. Once the established docks have been controlled it is best to keep the problem under control with follow-up treatments every year.  This controls new growth of seedling docks that appear as all that is required for dormant seeds to germinate is a gap in the sward caused by poaching or tractor marks.

In fertile soils, the dock root system consists of a large tap root with a highly branched mass of smaller fibrous roots. This means what appears to be a small dock plant above ground may in fact be growing from a large rooting system below ground. In order to achieve effective herbicide application docks should be at the rosette stage, with foliage8-10 inches high or across. If grass has been cut or grazed a period of three weeks must occur to allow sufficient regrowth and a suitable target for spraying. If applying FOREFRONT T, DOXSTAR PRO or PAS.TOR, livestock should be kept out of treated areas for 7 days before grazing and until the foliage of any poisonous weeds has died and become unpalatable. Where clover is important SQUIRE may be applied in establishes grass.

 

Chickweed

There are 2 types of chickweed, common chickweed which has a smooth leaf and is the most commonly found, and mouse-eared chickweed which has a larger leaf than common, with a very hairy surface on the leaf & stem. Chickweed levels have built up very quickly this spring as this weed grows at lower temperatures than grass, and should be treated as soon as possible to avoid choking out the young grass. Similarly, established swards that have been poached by autumn grazing tend to be very open in the early spring and this allows chickweed a chance to become a problem. Chickweed can mature and produce seed in 5-6 weeks hence there can be several generations in a year. Mouse-eared chickweed is very common on many local farms and it is important to note the distinct differences and treatments.Both ENVY andLEYSTAR will be used widely on new sown leys this season where clover is not important. As well as controlling both strains of chickweed it will give very good control of dock and thistle.

DOXSTAR applied at 1lt/ha, will control both types of chickweed in established swards. Neither will check the growth of immature grass plants and are not clover safe. Where clover is part of the mixture then a clover safe product must be used. TRIAD is an SU type herbicide that is safe to clover when used correctly. As well as controlling a wide range of BLW’s TRIAD gives excellent control on chickweed. It will also control seedling docks (not those regrowing from roots), but has no effect on thistles or buttercup. Add SPRUCE to bring in control of these weeds.

It is extremely difficult to achieve satisfactory control once weeds get beyond the seedling (young plant) stage. Clover content of the sward needs to be higher than is often appreciated. As a rule of thumb there should be 10 plants per square metre at the start of the season. Where plant populations are below this level it is more important to focus on other aspects and be prepared to treat the field as a grass only crop. High levels of nitrogen will significantly reduce clover growth, but by reducing nitrogen inputs overall forage yield will be reduced.

 

Time To Focus On Crop Nutrition

The extremely wet and windy weather over the last couple of weeks has delayed fertiliser and spray applications. Crops have begun looking for nitrogen and as daylight hours are longer it is essential to apply fertiliser onto crops as soon as ground conditions allow. The amounts of P&K at the target index 2 must be maintained and it is important to take into consideration the offtake in yield of grain when planning fertiliser applications. As most of our straw is removed an NPK fertiliser should be applied in accordance with the RB209 taking into consideration the use of organic manures. Cereals are becoming more responsive to sulphur as atmospheric deposition of sulphur declines. Where deficiency has been recognised or is expected 25-50kgSO3/ha as a sulphate should be applied in early spring before the start of stem extension.

Fastmix Magnesium Plus contains the following available nutrients- magnesium, sulphur, zinc and manganese. This product is rapidly absorbed by the plant quickly correcting deficiencies. Fastmix has been specially developed to meet the micronutrient demand of cereals and other leafy crops with a high manganese demand in an ideal combination with magnesium and sulphur.  It is a cost efficient nutrient application technique for Mg, S, Mn and Zn without additional costs, if combined with the regular crop protection program.  It also helps activate nitrogen into the plant to enhance seed development and transference of sugars throughout the plant, sulphur is one of 17 elements essential for crop growth. Although sulphur is considered a secondary nutrient it is often referred to as the fourth major nutrient ranking just below NPK. Sulphur deficiency can often be mistaken as nitrogen deficiency. The pale yellow symptoms of sulphur deficiency often appear on the younger or uppermost leaves whilst nitrogen deficiency initially appears on the older leaves.

Crops lacking sulphur appear stunted, spindly and thin stemmed and maturity in cereal grains is delayed. When deficient, Mg is transferred in the plant from older to new tissue. As a result, deficiency symptoms occur first in older leaves. Tissue between the veins becomes light green to whitish in colour. In cereals this leads to striping between veins that may be intermittent rather than continuous. With severe deficiencies, purple colouration may follow. I have observed quite a lot of mildew especially on winter barley crops across the province over the last couple of weeks. I am advising a T0 fungicide treatment as rhynchosporium levels have also become quite high. It is also important to observe the winter wheat varieties when considering a T0 bearing in mind the low resistance some varieties have to mildew.

Weed Control Starts in Wheat & Grass Reseeds

Autumn 2018 was again kind to us, allowing much of the winter barley and some winter wheat to receive a herbicide treatment during October and November. Mixtures of CRYSTAL and SEMPRA were widely used and by and large, performance has been excellent.

Control of Annual Meadow Grass (AMG) is the first priority in all crops if not already done with an autumn treatment. OTHELLO or HAMLET is an excellent contact solution for AMG in wheat in the spring, however there is no similar contact option for barley. None of the autumn products will control AMG beyond the mid tillering stage, yet they are the only AMG options for barley. Note that the actives in both HAMLET and OTHELLO that control AMG (iodosulfuron and mesosulfuron) will only control AMG that has already emerged; unlike the autumn actives these are not residual and have no pre-emergent activity. HAMLET provides a useful alternative to OTHELLO and is very effective on a wide spectrum of grass weeds. HAMLET has greater flexibility as the label allows a higher rate giving better activity in larger weeds. HAMLET works extremely well in cooler temperatures.

Both OTHELLO and HAMLET will also control a wide range of pre or early post emerged broad leaved weeds, but where these weeds have size then a contact product needs to be added to ensure larger overwintered BLW are controlled effectively. Where the AMG has been controlled in the autumn but for example over-wintered chickweed, cleavers or groundsel are problems weeds now, ZYPAR is a more effective option controlling these and most other emerged BLW.

Brome grass and wild oats

Brome grass infestations continue to be prevalent right across the province. Last season saw a decline in the numbers of infested fields, Effective control can only be achieved using a combination of cultural and chemical control methods. Cultural control methods (break crops, stale seedbeds).Chemical control then is a sequenced approach of an autumn treatment followed up with a spring treatment. CRYSTAL at 4lt/ha in the autumn was the first part, and should have been applied to wheat and barley. The follow-up then in the spring is BROADWAY STAR but note this product can only be used on wheat. There is no follow-up brome product available for barley and therefore in a severe infestation situation, only wheat allows effective control.

To avoid crop damage, do not spray any crop under stress. Note that performance of some wild oat/brome herbicides can be adversely affected by other herbicides used on the crop. To avoid these antagonisms, a minimum time interval must elapse between applications of the various herbicides.

Need a T0 Treatment?

Rhynchosporium and Septoria are the two most damaging cereal diseases in NI. Both have always been more effectively controlled protectantly, but in previous times where the curative properties of the azoles were able to rescue a bad situation later, particularly in wheat this is no longer the case. Growers must now change their approach, looking to keep ahead of both diseases by starting earlier than before and maximising the protectant activity of the chemistry available then right through to crop senescence.

In barley the lower leaves contribute more to grain fill than the upper leaves and therefore particularly in a year like this where crop was drilled early last autumn, plants are forward and disease is already present, so a relatively cheap T0 applied within the next few weeks will reduce the level of inoculum present keeping the newly emerging leaves clean and allow the T1 be better timed and protectant focused. Most of the azoles still have good curative activity on Rhyncho and the addition of morpholine will help control the high level of mildew present.

Treating Chickweed In Reseeds

There was a large amount of reseeding of poor performing grass fields last autumn. Now is a good time to check whether a herbicide spray is required to clean these fields up. Getting rid of annual weeds such as chickweed or seedling perennial weeds such as docks and thistles, is vital to ensure the investment in reseeding realises its full potential.”

Even though only an annual, chickweed is the most competitive and potentially damaging weed to new grass leys. This year’s mild winter has allowed chickweed to become very strong and competitive in the sward. If not controlled, chickweed levels will build up and will very effectively choke out the young grass; populations of 10plants/m2 can reduce the ryegrass population by as much as half. Therefore chickweed should be treated as soon as possible if ground conditions allow.

Whilst in the past many hormone herbicides had approvals for use on new sown leys, in recent years almost all of these approvals have been revoked, and the range of products today is limited to a handful. Product choice will be dictated first depending on whether clover is an important part of the reseed mixture or not. Where clover is important, broad spectrum product choice is limited specifically to TRIAD in mix with SPRUCE. Where clover is not important, the choice is essentially between ENVY and LEYSTAR depending on which weeds are to be controlled. Leystar from Corteva Agriscience has three effective active ingredients, fluroxypyr, clopyralid and florasulam, which combine to control a wide spectrum of annual weeds, such as fat hen, red shank and mayweeds, as well as seedling docks and thistles.

Leystar can be applied from 1 February to 31 August in new sown leys in 200 litres of water, so can be used on autumn-drilled and spring-sown grass reseeds. It has good grass safety, but will kill clover or any broad-leaved weeds that have not germinated when the herbicide is sprayed..

For best results apply to weeds that are small and actively growing, and when the grass has reached the three-leaf stage.

ENVY is an excellent herbicide choice for autumn reseeds as it works very well in cooler temperatures. ENVY can be applied between 1st February and 30th November. Trials done with ENVY have shown excellent results on chickweed much better than straight fluroxypyr.

Allow an interval of four weeks after application before cutting grass to optimise the effect of the herbicide. Do not roll the grass for ten days before or seven days after application. If the fields are to be grazed, animals can return just seven days after application. Farmers must be certified to use professional use herbicides on their fields.

Kerb Granules – Weed Free Trees & Shrubs!

Welcome to the first crop crack of 2019. It is possible to still achieve excellent weed control for some weeks yet in situations on farm, commercial forestry, ornamental plantings and recreation areas.

Season long control of grasses and most broad-leaved weeds is possible by applying Kerb Granules at this time. KERB is a pre- and post-emergence residual herbicide for the control of annual and perennial grasses and a wide range of other weeds. Propyzamid the active ingredient in Kerb works by inhibiting cell division, disrupting the growth process and leading to eventual death of the weed. Kerb can be applied to all soil types, therefore allowing its use in many areas where weed control is needed.Kerb is the ideal herbicide for forestry and woodland (including farm forestry), ornamental shrubberies and rose beds, hedges, fence lines and gravel pathways. Where shrub beds are mulched Kerb Granules must be applied immediately prior to mulching if weeds are to be prevented from growing through the mulch.Kerb requires soil moisture for root uptake to take place. KERB Granules are mobile in the soil profile and therefore the best results will be achieved when applying in cooler conditions, usually between October and February. If warm, dry conditions prevail after application then weed control may be reduced. Although KERB can be applied in all weather conditions, application to severely frozen ground should be avoided if there is any risk of surface run-off.KERB Granules is non- irritant, non-sensitising and has no known bio-accumulation which gives you the confidence to use this product in areas open to the general public. For further information contact your local agrochemical merchant.

Keep New Leys Weed Free This Autumn

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Programmed Approach Required To Tackle Brome Grass

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Autumn Drilling Progressing Well

Soil conditions are excellent for cultivation at the moment, and there is a lot of field work going on, mainly grass reseeding , but also the drilling of cereals. With a longer gap than usual between harvesting and drilling autumn crops, some stale seedbed cultivations have been carried out, to assist control of brome and other problematic grass weeds.

Be aware though, early drilling of crops brings its own problems. When temperatures remain mild, aphids numbers remain high and will quickly move into new crops as these emerge, therefore increasing the likelihood of BYDV infection in all emerged winter crops. Early drilling also increases the likelihood of disease infection. Lush crops of winter barley going into the winter are much more susceptible to Rhyncho and Mildew, as was prevalent last winter. Early drilling of winter wheat in particular significantly increases the likelihood of Take-all and an appropriate Take-all seed treatment should be applied as a matter of course. Winter oats are particularly susceptible to Mildew.

Annual meadow grass and broad leaved weeds

Annual meadow-grass (AMG) continues to be the most problematic weed in autumn cereals. If not properly controlled, this weed grass will continue to grow throughout most of the winter and once well tillered is impossible to control effectively. Flufenacet, available in various mixes, is the principle active in autumn herbicide programmes to control AMG, giving pre and post emergent activity of the weed grass. It has limited broad-leaved weed activity but is very effective on a wide range of other grass weeds, including all species of brome. Whilst HAMLET and OTHELLO are effective alternatives to flufenacet for controlling AMG in winter wheat, in the early spring, there are no such options for barley, rye or oats. The key to effective control in winter barley and rye is to apply flufenacet (not oats) before or soon after emergence of the crop, critically before the AMG has begun to tiller. Only when soil temperatures have dropped, pre-emergence of the crop is very effective and with GPS technology this is an option.

Other actives used at this time include pendimethalin (PDM) and diflufenican (DFF). PDM is also active on AMG but pre-emergent only. It is relatively insoluble and so persists for an extended period in the soil. PDM also has a wide broad leaved weed (BLW) pre-em spectrum, including chickweed and fumitory, but not groundsel. DFF is a residual with both pre and post emergent activity. It has no AMG activity but has a wide spectrum of BLWs including large chickweed and field pansy, but no activity on fumitory or groundsel.

FMC (formerly Headland) have introduced a new broad spectrum autumn herbicide called NUCLEUS, containing flufenacet and DFF. Whilst the grams of both actives are the same as LIBERATOR and therefore performs in an identical way in the field, NUCLEUS has a broader label with full approval for use on winter rye and triticale, alongside winter wheat and barley.

The persistency of any herbicide product that has residual activity is directly linked to soil temperature – the lower the temperature the longer the duration of its persistency. As soils cool in the coming weeks and months, product performance will improve the longer application is delayed into the winter.

Soil acting herbicides also require adequate soil moisture to work, but a persistently wet winter will also adversely affect performance, the more soluble actives being leached out of the soil, before the crop canopy has sufficiently covered the soil surface to prevent a late weed infestation reoccurring.

Manganese Deficiency

In known deficient soils, manganese should be applied during November. Treatment of the condition before deficiency symptoms are seen will mean stronger healthier plants going through to spring. A follow-up treatment should also be applied in the early spring.

 

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