Crop Crack

Time For Pre-Harvest Roundup

Pre-Harvest Glyphosate

Winter barley crops are ripening well and thoughts will now turn to grain quality, moisture levels, and ease of harvesting. This year in particular grasses and other weeds are a real problem in many fields. Pre harvest application of glyphosate is an essential tool to improve the efficiency of harvesting, giving a range of benefits:

Harvest management

-all green tissue removed – ripens any green stems, leaves and pickles  allowing cutting to start earlier in the day & continue for longer

-no green pickles reducing overall grain moisture and drying costs

-less grain lost over straw walkers caused by green material during threshing

-faster straw clearance reduces length of weather window required

-limits sprouting in laid crops


Scutch & general weed control

-the most effective time to control scutch in tillage ground

-desiccates any other green grass & broad-leaved weeds present, facilitating lower grain moisture, faster harvesting and sooner baling of straw

Note however, do not use glyphosate on any crops where seed may be saved for re-sowing.

Independent trials carried out over a number of years in GB looking at the effect of using Roundup in various replicated treatments consistently show moisture contents being reduced by 2.0-2.5% at harvest compared to plots where no treatment is applied.

With a wide range of glyphosate products available, which offers the best performance in the field, and best value for money? First off, it is not the price per drum that should be compared. With different formulation types having different strengths of active per litre and therefore different rates of use, it is the price per acre treated that should be compared, and what level of performance is being obtained from each. Glyphosate itself is not very soluble therefore it depends very much on the salts and wetters to enhance its performance. The potassium salt in Roundup Energy is  taken up significantly faster than isopropylamine salt; as a result ENERGY is rainfast within 1 hour of application and cultivation can commence as soon as 2 days after application whereas the IPA glyphosate products need a minimum of 6 hours to be rainfast and 5 days minimum before cultivating.

Application should be made once the grain moisture gets down to 30% or below, ideally 10-14 days (and not less than 7 days) before cutting. An easy and reliable test to estimate this 30% moisture level is to press the thumbnail into a number of grains; if the indentation holds on all the grains the crop is ready for spraying.


Grassland Weeds Coming Back After Silage Cutting


Attention must now be given to those fields which were not sprayed prior to first cut. Grassland herbicides use growth function to kill weeds, therefore peak growth periods should be used for herbicide application. There must be sufficient growth to allow herbicides to be effective and vegetative growth is the key time to apply, as the chemical then gets drawn down into the roots. Herbicides are less successful once plants have progressed to the reproductive stage and have thrown a stem or began to seed. Once weeds are beyond the ideal growth stage for spraying, they should be mowed or topped and allowed to regrow again, and a herbicide applied to the fresh young growth.

To optimise efficacy of any herbicide, recommended water volumes should be observed, even when it means more time spent spraying. It is important to note ragwort plants in their second year are now coming close to flower and should be sprayed immediately as flowering ragwort is poorly controlled. The routine herbicide treatments for this weed are full rate MCPA or 2, 4-D, and they are most active on growing rosettes with reduced activity as the stem starts to extend. They are not clover safe. You can use a mixture of both these products as Nufarm Lupo which allows an increased dose herbicide compared with either alone, with a consequent activity benefit. Forefront is also very effective on ragwort. Stock must be kept off until the weeds have rotted away, which can take up to six weeks.

Buttercups are now ready for treatment. Best results are achieved if sprayed before flowering. ENVY is very effective on both buttercup and dandelions. Envy contains florasulam and fluroxypyr. Together they deliver excellent control of weeds found in pastures which typically get over grazed, receive minimal nitrogen or have poorly competing grass species present. Envy has no manure management restriction and has a short seven-day stock withdrawal period so animals can return quickly. Envy is very safe to grass and won’t hold back its growth. Buttercups are best controlled when they are still green and leafy and before the main flowering period. You will still get control during flowering but for the best effect treat now. Product choice depends very much on which other weeds are being targeted. Where clover is important SPRUCE may be applied to control buttercup.



Where broad –leaved weed control has yet to be completed and the crop has passed the latest timing for Sencorex a reduced rate of Sencorex tank-mixed with Titus will provide a wider weed spectrum of weed control than Titus used alone and can be used on emerged crops up to 25cm high where the label allows .Scutch, other grasses or volunteer cereals are not controlled by the Titus/Sencorex mix. Where these weeds become a problem in coming weeks the graminicide Falcon can be used. Falcon can cause transient yellowing and is therefore not approved for use on seed crops.

As canopies close, the soil surface will tend to remain damper, encouraging slugs onto the soil surface. Timing is critical for effective control, just before the crop meets across the rows. Take advantage of any rainfall by applying pellets just afterwards, as this will bring slugs up onto the soil surface. Potato varieties particularly susceptible to slug damage include Maris Piper, Desiree and Kerrs Pinks.

Blight fungicides move through the plant in three different ways contact, translaminar and systemic. Dithane, Shirlan and Tizca are all contact fungicides. These Products protect only the outer surface of the leaf onto which they are deposited.Translaminar products such as Curzate M, Invader and Ranman Top move into the leaf and redistribute throughout the leaf tissue as it increases in size whilst systemic products such as Zorvec and  Infinito move in through the leaf surface and upwards into the new growth protecting this from infection also. Products that have zoospore activity are the most effective 1st spray, applied at the rosette stage prior to rapid haulm growth. Shirlan or Tizca will control any zoospores that may be in the soil and provide good protection of the new plant. During the main canopy development phase with the considerable amount of new growth it is essential the product being used is fully systemic to properly protect the new leaves being put on between applications. Later planted crops are higher risk as they produce more new growth between applications than earlier drilled crops, at a time when the level of inoculum in the air is progressively increasing. The way the blight product is applied is as important as the product choice. Make sure nozzle type used is correct to ensure sprayer pressure; droplet size and water applied is as directed on the label. Inspect and calibrate nozzles regularly to maintain performance. Never use any blight product at reduced rates. Do not spray when the leaves are wet as this will significantly increase the likelihood of runoff.


Crops Racing Through Growth Stages

Crop Nutrition

Most spring cereal crops continue to benefit from the recent hot weather with many racing through the growth stages in a matter of days. However the late planting in May and dry weeks since make a challenging combination. With temperatures well above average and daylight hours considerably longer than for a crop drilled in early April, such conditions increase the likelihood of crop stress through too little moisture, or not enough nutrient availability to support the potential rate of growth. As a result many fields are beginning to show variation of colour and growth, and such variation is very difficult to address in a satisfactory way. Manganese (Mn) deficiency is widespread in much of our local soil types, and particularly damaging 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.

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. 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.  Applying Cereal Plus High N will help your crop overcome these deficiencies.  Cereal Plus High N supplies 250gm Nitrogen, 125gm Sulphur, 93gm Manganese, 38gmMagnesium, 45gm Copper and 15gm Zinc per hectare.Winter cereals are struggling for moisture at present especially winter barley. Disease pressure has been lower than that seen for a long time and fungicides are now complete on winter barley. As temperatures are now a bit lower hopefully this will cause less stress on the flag leaf asT2 applications should now be done on winter wheat crops.



Spring Barley

Dry conditions have held back disease and at present all crops are fairly clean, but in our typically moist climate the likelihood of Rhyncho and Net blotch infections breaking out are inevitable unless controlled in good time.

Even where crops are considered to be clean, controlling Rhyncho early is much more effective than leaving it until it is seen. Once this disease comes into the crop, any eradicant treatment has limited efficacy, will stress the crop and increase the risk of Ramularia infection.


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, GS31-32, 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.

Lodging Control

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 has happened this season because of late planting and high temperatures) 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/Moddus 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.

Selon applied at mid to end of tillering (GS23-30) on spring wheat gives reliable later season lodging control, therefore it is less likely that spring wheat will need a growth regulator towards flag leaf unless the crop is particularly dense.

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