Wendy Fearon

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.

There have been several blight warnings recently and it is important not to stretch spray intervals at this critical time. Combines have been busy in many areas over recent weeks but this week it has been a bit stop start. I would urge all farmers to assess both land intended for reseeding and winter cereals to monitor for slugs as numbers are greater than they have been for some years. Treated seed is a priority if slugs are present. I would like to impress on you the need to carry out soil samples at this time to ensure all nutrients will be readily available to the growing crop.

Grassland Weed Control

Ragwort is appearing in many grass situations at present and is becoming a greater problem especially in lower fertility situations; it is an ‘injurious weed’ and is not permitted to grow unchecked. Ragwort is a biennial plant i.e. it grows from seed the first season to produce a rosette plant and then the following season it will produce a flowering stem, produce seed then die. Ragwort contains alkaloids which are poisonous to all livestock. Each plant can produce up to 150,000 seed with a 70% germination rate and seeds can remain dormant in the soil for up to 20 years. Treatment of plants, which are at the rosette stage now, can be very effective and an autumn application allows a check on the efficacy of the treatment to be made in early spring before allocating fields for silage or hay. Autumn is a good time to spray as the grass growth slows down and grass utilization and withdrawal periods are not as critical as they can be in the spring time when stock are turned out. Whilst ragwort is unpalatable when it is green it becomes extremely palatable once sprayed. It is important to remove as much of the root as possible; ragwort can regenerate like docks from its root fragments. A single application of weed killer is unlikely to completely eliminate a ragwort infestation due to overlapping generations of the weed. A follow up treatment should be made in the spring.

Docks are a particular problem in intensively managed grassland, especially where seeds are spread through slurry applications or poaching has occurred. Docks look unsightly, but more importantly, can reduce the grass yield and productivity. Early autumn is often overlooked as a potential time to achieve effective dock control. At this time the dock plant will revert back to vegetative growth. During vegetative growth the plant food being produced in the leaf is moved into the root for storage. Translocated herbicides are moved through the plant along with the food, hence if they are applied at this stage more product will end up in the root giving better root control.

Where clover is not considered important products such as Doxstar, Pastor and Forefront should be used. If clovers are an important component of the sward Squire Ultra should be used .Remember in most circumstances treatment is most effective where a second application takes place within a 12 month period.

Potatoes

Growers should continue to maintain fungicide protection of the haulm until the crop is harvested or the haulm is 100% desiccated. Timely desiccation is an essential part of good seed and ware production. Diquat is the most widely used farmer applied chemical desiccant .The rate of haulm desiccation is slow and therefore fungicide protection should continue after application. Even after two split applications of Reglone certain varieties of potatoes are difficult to burn off completely and be certain no regrowth will appear. Spotlight Plus is a desiccant recommended for use after a 7 day interval as a follow up T2 treatment to the T1 application of Reglone and gives complete kill of any stems remaining and stolons below the ground but it is poor on leaves.

There have been several blight warnings recently and it is important not to stretch spray intervals at this critical time.

Combines have been busy in many areas over recent weeks but this week it has been a bit stop start. I would urge all farmers to assess both land intended for reseeding and winter cereals to monitor for slugs as numbers are greater than they have been for some years. Treated seed is a priority if slugs are present.

I would like to impress on you the need to carry out soil samples at this time to ensure all nutrients will be readily available to the growing crop.

Grassland Weed Control

Ragwort is appearing in many grass situations and is becoming a greater problem especially in lower fertility situations; it is an ‘injurious weed’ and is not permitted to grow unchecked. Ragwort is a biennial plant i.e. it grows from seed the first season to produce a rosette plant and then the following season it will produce a flowering stem, produce seed then die.  Ragwort contains alkaloids which are poisonous to all livestock. Each plant can produce up to 150,000 seed with a 70% germination rate and seeds can remain dormant in the soil for up to 20 years. Treatment of plants, which are at the rosette stage now, can be very effective and an autumn application allows a check on the efficacy of the treatment to be made in early spring before allocating fields for silage or hay. Autumn is a good time to spray as the grass growth slows down and grass utilization and withdrawal periods are not as critical as they can be in the spring time when stock are turned out. Whilst ragwort is unpalatable when it is green it becomes extremely palatable once sprayed. It is important to remove as much of the root as possible; ragwort can regenerate like docks from its root fragments. A single application of weed killer is unlikely to completely eliminate a ragwort infestation due to overlapping generations of the weed. A follow up treatment should be made in the spring.

Docks are a particular problem in intensively managed grassland, especially where seeds are spread through slurry applications or poaching has occurred. Docks look unsightly, but more importantly, can reduce the grass yield and productivity. Early autumn is often overlooked as a potential time to achieve effective dock control. At this time the dock plant will revert back to vegetative growth. During vegetative growth the plant food being produced in the leaf is moved into the root for storage. Translocated herbicides are moved through the plant along with the food, hence if they are applied at this stage more product will end up in the root giving better root control.

Where clover is not considered important sprays based on the chemicals fluroxypyr, triclopyr or dicamba mixtures should be used. If clovers are an important component of the sward Squire may be used .Remember in most circumstances treatment is most effective where a second application takes place within a 12 month period.

Potatoes

Growers should continue to maintain fungicide protection of the haulm until the crop is harvested or the haulm is 100% desiccated. Timely desiccation is an essential part of good seed and ware production. Diquat is the most widely used farmer applied chemical desiccant .The rate of haulm desiccation is slow and therefore fungicide protection should continue after application. Even after two split applications of Reglone certain varieties of potatoes are difficult to burn off completely and be certain no regrowth will appear. Spotlight Plus is a desiccant recommended for use after a 7 day interval as a follow up T2 treatment to the T1 application of Reglone and gives complete kill of any stems remaining and stolons below the ground but it is poor on leaves.

Grain Store Hygiene

Some winter barley crops have been harvested. In order to ensure harvested crops are kept free from pests,stores need to be thoroughly cleaned to ensure any debris that may be harbouring pests is removed.Pests arise from within the store and not from harvested grain.Reldan 22 can be applied to empty stores to combat grain store pests.

Potatoes

The risk of blight remains high with great variations in particular areas due to localised showers. To try and keep crops free from blight where pressure is severe, requires short intervals appropriate for high risk and also the use of fungicide products with curative activity. Fungicides with good rainfastness will be very beneficial given the current spells of heavy rain, especially because it’s been difficult to accurately predict the timing and location of showers.

Propionic Acid

Propionic acid has an energy value of 1.5 times that of barley, so as well as preserving the grain it also adds to its energy value. With Propionic treatment, harvesting can take place when there is still surface dampness on the grain, dew or rain. Harvesting can start earlier in the morning or after rain and continue later at night, giving a quicker more flexible harvest, which leaves extra time for autumn cultivations. By harvesting before grain is fully ‘ripe’ a higher yield is also obtained, reduced shedding losses may save 200kg per hectare.

Natural vitamin E levels in moist grain, whether treated or not, are destroyed during storage. When moist grain forms a major part of the diet a mineral/vitamin supplement high in vitamin E should be used.

Grain at 18% moisture will require application of 7 to 8 litres of propionic acid per tonne and an additional half a litre added for each percentage of moisture above 18%.  Application to rolled cereals or beans should be increased by 10%.  Moisture levels should be checked regularly during the day to ensure that the correct application rates are used as it has been well established that under treatment of grain will fail to halt mould and bacterial activity.  The flow rate of the auger should also be checked to calculate the treatment rate

Treated grain can be stored simply on a dry floor. It should not be stored with untreated grain.

The rising temperatures over the last couple of weeks have been very welcome for all crops, but unfortunately awns have appeared very quickly on winter barley with critical plant growth regulator timings missed. In spring barley & spring wheat an early application of SELON increases root development and the numbers of surviving tillers which will improve crop establishment and yield. Due to the more rapid progression through the growth stages in spring crops, the growth regulator must be applied very early to maximise the suppression of apical dominance and therefore divert nutrients and growth to promote secondary tiller development. Optimum timing for barley is from the 2nd expanded leaf stage to beginning of tillering, GS12- 21 whilst in wheat the optimum timing is slightly later, 5 leaf to mid tillering, GS15-24. This treatment also gives a consistent straw shortening effect in wheat, but not in barley.

Spring Barley

To minimise the effects of competition on the crop and optimise the level of weed-control, the herbicide application should be carried out sooner rather than later, once all the weeds have emerged but are still small, and before they begin to compete with the crop for nutrients and light. Product choice depends on the weed type and size present and crop growth stage. Broad leaved wise, Sulfonyl-urea (SU) herbicides will likely be the starting point, controlling a wide range of weeds and are very safe to the crop. However they must always be tank-mixed with another BLW herbicide to control SU resistant weeds (chickweed) and those weeds not controlled by the SU’s (cleavers, fumitory and fat-hen). Ideal partners are Compitox,Minstrel and Starane.I have found over the last couple of years the Spitfire, Foundation mix to be the belt and braces for weed control in spring cereals. Each of these partner options are very tank mixable, and other products such as SELON and MAXMAN can also be safely added.

Where the range of BLWs present are limited to chickweed, redshank, fat hen, fumitory & day nettle, the hormone mixture products will work well without the need to tank-mix, but must be applied by GS31. Where the likes of field pansy, forget-me-not, speedwells & corn-marigold are also present however, sulphonyl-ureas products will improve control. Spring barley, spring wheat and spring oats undersown with grass and clover should be treated with TRIAD and where clover is not important MIRCAM PLUS should be applied. If seedling docks, thistles and buttercup are also problem weeds, SPRUCE must be added to the TRIAD to improve control of these also. SPRUCE is 2,4DB, a clover safe hormone type herbicide.

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 high disease pressure and declining kickback activity from core chemistry, the T2 timing becomes even more critical to ensure effective product performance.  Managing resistance and maintaining reliable disease control now means using a range of different actives over the course of the growing season. Therefore ensure there are a number of different modes of action are in the tank at every treatment, that way maximising the range of strains sensitive to the mix. SDHIs are now regarded as essential partners to triazoles to maximise the yield of all but the poorest crops, adding both to curative as well as preventative activity. Having a completely different mode of action to the triazoles, they will improve the kickback activity of the treatment, as well as widening the spectrum of Septoria strains controlled.  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.

Potatoes

With planting progressing well to date, this year’s crop is going in in almost perfect conditions right across the Province. Drills are moist and with increased temperatures rapid emergence of both crop and weeds will occur. Therefore growers should be planning weed control now, taking good advantage from the moist soil conditions. Most weed control programmes are based on residual products ie products that are taken up through the soil, and are therefore very dependent on sufficient soil moisture to work effectively. Soil conditions are ideal therefore at the moment, moist enough on the tops of the drills to allow the herbicide be taken into the soil and taken up by the germinating weeds. Contact products such as RETRO,ROUNDUP and TITUS may be applied. All require the inclusion of a residual partner to maintain clean drills up to the time of the crop canopy closing the drills. Residual products are DEFY, SENCOREX, AFALON and GAMIT.

All potato herbicides carry timing restrictions and some, namely SENCOREX, have varietal restrictions and it is therefore important to seek advice on the best product choice

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 will have 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.

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 PASTOR, 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.

PASTOR applied at 2lt/ha, 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 this will increase the concentration of sugars and reduce effluent production.