News

The last couple of weeks have offered a good opportunity for farmers to get up to date with much needed fieldwork. Grass growth has been slow due to low night time temperatures but chickweed has grown away through the winter and will need controlled especially in autumn reseeds. The presence of broad-leaved weeds will always take away from grass yield and quality. Docks and chickweed are nutrient loving weeds, thriving in nutrient rich regimes, ie more intensively managed swards.  Docks have only 65% of the feed value of grass and are unpalatable to stock.  Where infested swards are ensiled, their high nitrogen content adversely hampers a good fermentation, so leading to high pH silage that spoils quickly when opened and depresses intake. Dock seeds can also survive in silage and pass through the cow, infesting a field where slurry has been spread. The best defence against perennial broad-leaved weeds is to stop them establishing in the first place. This can be achieved by having a well-managed, dense sward, growing in well-structured non-compacted soil.  Over or under-grazed leys that have been poached, offer perfect conditions for weed seeds to germinate. Topping or mowing weed plants provides short-term visual satisfaction but stimulates active regrowth – so the problem gets worse not better. The long-term solution for controlling persistent weeds in grass is to use modern systemic herbicides. A well-timed treatment with an appropriate herbicide can transform a weedy pasture into a productive ley, without the need for costly reseeding.  Farmers may have to be more pro-active this year, as weeds have generally survived the mild winter and kind spring, so weed numbers are much higher than usual. As many of our traditional herbicides have disappeared this season we will need to choose alternatives. Pastor Pro from Dow has been replaced with a new agronomy pack PAS•TOR.  Another new product for grassland is LEYSTAR which has approval for use on new sown leys delivering a very wide spectrum of weed control. This product is not clover safe. THRUST from Nufarm is also new to us for 2017 and is very effective on docks, thistles and ragwort and again is not clover safe. So whilst we have lost some of our grassland products we have also now in our possession some very effective new armoury.

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.

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 will reappear because 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 is the most commonly found type, with a smooth leaf 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.  LEYSTAR 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.

PAS.TOR applied at 1lt/ha of PAS and 1lt/ha of TOR, and DOXSTAR applied at 1lt/ha, will control both types of chickweed in established swards. Neither will check the growth of immature grass plants but 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 also.

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.

To ensure a well fermented silage sufficient fertiliser must be applied at the correct time for intended cutting dates. On average allow one day’s growth for each 2-3 units of nitrogen between application and cutting. The younger the grasses the higher the feed value but the lower its yield. In general aim to cut before 50% of the ears have emerged to gain as much yield as possible. Short chopping speeds up fermentation and aids consolidation ensuring not to cut too short as long fibre is required for rumen function. Where conditions allow fast wilting in good weather will increase the concentration of sugars and reduce effluent production.

WINTER BARLEY

The increases in temperatures over the last couple of weeks have made a marked impression on winter crops as they start to grow. Yellowing and patchy areas are becoming evident across fields as a result of localised variations in soil conditions varying the availability of N, P and K to the crop; wetter spots and compaction on headlands in particular are now showing up. Depending on when and if a T0 treatment was applied, diseases are prevalent in all fields, with mildew levels higher than those seen in recent years. All have completed tillering, with the most forward approaching 1^st node GS31. A considerable area of winter barley crops received this treatment during the latter half of March this year and disease levels now being seen reflect this, with higher levels of both Rhyncho and Mildew present higher up the plant in those not treated.

Winter Wheat

Growth stages are more varied depending on drilling date, varying from mid tillering, GS23 to the most forward at 1^st node GS31. Most are looking well with less yellowing than the winter barley. Some received a T0 and infection is markedly lower in the youngest leaves of these crops, but Septoria is present and moving upwards in all fields with varying levelsl of Mildew. There have also been reports of yellow rust in some winter wheat varieties, especially Reflection.

The pleasant weather over the last week has got most of us thinking about fertiliser and spray applications.  Crops have begun looking for nitrogen and as daylight hours are longer it is essential to apply fertiliser onto crops to maintain healthy foliage.  Who knows what the next few weeks have in store for us so it has been my advice to get on as soon as possible with fertiliser.  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  often appear on the younger or uppermost leaves whilst nitrogen def 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. Infinity seems to be the weakest variety against this disease but I am also seeing it on other varieties. I am advising a T0 fungicide treatment as rhynchosporium levels are also quite high.It is also important to observe the winter wheat varieties when considering a T0 bearing in mind the low resistance the variety Leeds has to mildew. Whilst this has proved to be an excellent yielding variety it is critical to be aware of this when planning fungicide programmes.

Weed control decisions for winter cereal crops will depend on what has already been done in the autumn and what weeds have overwintered since that treatment. Where no treatment has yet gone onto wheat, Othello is the product of choice, controlling AMG and certain broad leaved weeds (BLW) in this crop in the spring. However this product is not safe to use on barley, and with the loss of chlortoluron (CTU), there is no spring alternative to control emerged AMG in this crop. None of the autumn products control AMG beyond the mid tillering stage, and in all winter barley crops the AMG will be well beyond this stage now. With the loss of Lexus Class there is nothing to control emerged grass in winter oats.

Unlike the autumn actives, the actives in Othello that specifically control AMG (iodosulfuron and mesosulfuron) are not residual and have no pre-emergent activity, and therefore will only control AMG that has already emerged. In addition they require the weeds to be growing actively, so delay use until all grasses have emerged and temperatures have risen to allow growth to have resumed.

The third active in Othello, diflufenican has residual activity as well as contact and therefore will control a wide range of pre or early post emerged broad leaved weeds. However where these weeds are well established beyond the seedling size, then a contact product needs to be added to ensure larger overwintered BLW are controlled effectively. The cheapest option is Duplosan, improving control of chickweed, fumitory and cleavers, but this product is temperature sensitive, therefore needs a milder spell to work properly.

In past years both IPU and CTU controlled groundsel very effectively in the autumn. However none of the current autumn replacements control this weed, and therefore it is now a common overwintered problem requiring control in the spring. Other overwintering/late germinating weeds can include chickweed and cleavers. Spitfire is a more effective option controlling these and a wider range of other emerged BLW, and is the best tank-mix option with Othello in wheat or for use alone in barley and oats. As it is also a contact post emergent only herbicide, it works also best when the weeds are growing actively.

Brome grass and wild oats

Satisfactory brome grass control can only be achieved using a combination of cultural and chemical control methods over the course of the growing season; no single herbicide treatment is effective by itself. Cultural control methods are based around stale seedbed routines pre-drilling, switching to spring cereals, or the use of a break crop for a season.

Chemical control should have begun in the autumn with Crystal applied at the higher 4lt/ha rate, following up now in the spring with Broadway Star, but note this product can only be used on wheat. There is no spring follow-up product safe for barley; therefore some re-infestation of brome is likely in this crop in the spring.

To maximise the efficacy of Broadway Star, it is important to pay attention to a number of points;

-the smaller the brome, the better the control; ideally not after 3 tillers, GS23

-apply when soil temps at 10 cm are >8ºC and air temp >7ºC for 4 days before and after application

-apply to crops that are actively growing and not under stress

-always use an adjuvant along with the BROADWAY STAR

Because BROADWAY STAR works by contact activity only, any brome or wild oats that germinate after the application will not be controlled. The addition of a residual therefore such as pendimethalin brings control of brome and wild oats germinating after the BROADWAY STAR application.

Growth regulation – managing tiller numbers

When applied before 1^st node, GS31, application of certain chlormequat growth regulators can significantly increase tiller numbers. Chlormequat works by suppressing apical dominance, ie main stem development. In doing so it diverts the plant’s resources into producing and supporting more tillers. Particularly in wheat but in barley also, more tillers will go a long way towards compensating for low plant counts, ultimately increasing yield.

Optimising timing is important to maximise this effect. The earlier it is applied during tillering the greater the tiller effect, but note early application to increase tiller numbers will also reduce its effect on lodging. Application of a chlormequat based growth regulator often goes on with a T1 fungicide application sometime around 1^st-2^nd node, GS31-32. At this timing it is too late to affect tiller numbers and survival but will maximise the stem stiffening effect.

Early application will also increase root growth and so reduce stem-base lodging.   Stem-base lodging is where the plant folds over at the soil surface as a result of poor anchorage in the soil, and is caused by poor root ball development, more likely when the seedling develops in wet soils that limit root development.  Only chlormequat works by suppressing apical dominance, but the active itself does not work effectively at temperatures below 8°C.  SELON is a formulation of chlormequat in combination with a particular adjuvant mix which enhances the uptake of the chlormequat in low temperature conditions and therefore improve the reliability of performance, consistently working right down to 1°C. The adjuvant mix also works as a crop safener, particularly when applied in tank-mixes with other pesticides.  SELON is very flexible in terms of crop timings and tank mixes.

Welcome to the first crop crack of 2017. It is still possible to achieve excellent weed control for some weeks yet, in hedgerows, commercial forestry, ornamental plantings and recreation areas using Kerb Granules.

Season long control of grasses and most broad-leaved weeds is possible by applying Kerb Granules at this time of year. 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 Granules 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 Granules 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 are 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.