Crop Crack

Thoughts Turn Towards Harvest

All winter barley crops are looking well and the gates are now closed until desiccation pre-harvest. Most winter wheat crops have received their T3 earwash with a few later drilled crops still to be sprayed.  The cornerstone for the T3 head spray fungicide remains the double dose triazole mixes, despite their decline in Septoria efficacy.  Tebuconazole is the most effective triazole for Fusarium in particular and an important active in its own right at this time.  The addition of a strobilurin is essential to maximise the persistence of the triazole, to strengthen activity on Yellow Rust, and delay early leaf senescence. Good grain fill is totally dependent on retaining green leaf area for as long as possible, and the addition of the strobilurin extends the retention of green leaf tissue. ADHB trials continue to show pyraclostrobin (COMET) to be the highest rated strob for use in wheat, being the strongest performer on Yellow rust and the late ear diseases.

Aphids in cereals

As the grains begin to fill the aphids begin to feed at its base on the ear, drawing off the sugars that should be filling the grain if left unchecked. Growers need to continue checking crops for aphids right up to early milky ripe stage (GS73) in barley, late milky ripe (GS77) in wheat, and spray if present in numbers. Where aphids are not present, unnecessary application should be avoided as any insecticide application at this time is not bee friendly. Of the aphicides approved for use for this purpose, SUMI-ALPHA is the least harmful to bees.

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 the level of performance is being obtained from each. Glyphosate itself is not very soluble, therefore it depends very much on the salts and wetter’s 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.

Potatoes

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,Ranman Top, 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 Revus move into the leaf and redistribute throughout the leaf tissue as it increases in size whilst systemic products such as 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 and  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 at 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.

 

Dry Weather Challenging For Young Crops

Most crops continue to benefit from the recent hot weather with many racing through the early stem elongation 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 much or 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 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.

Spring Barley

Dry conditions have held back disease and at present all crops are 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. The T1 application should be applied at the end of tillering to the start of stem extension, GS24-31. The T2 is then applied 3-4weeks later during late flag leaf emergence to booting, GS38-49.

Product options continue to be 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 continue to improve the performance of the triazole partner, improving Rhyncho, Net Blotch and Rust activity. MOBIUS is a mix of prothioconazole and strobilurin, and is one of the strongest barley products available. SDHIs will also give very good disease control at T1 but if they are only going to be used once then the T2 timing is the better fit for them as it is the most responsive timing in spring barley. Chlorothalonil is also an important component, enhancing the control of Ramularia when applied onto the flag leaf and ear.

 

All trial work continues to underline the responsiveness and therefore improvement in yield and margins of spring barley to a correctly timed 2-spray fungicide programme, consistently outperforming a single application programme. The ‘single hit’ approach attempts to provide protection for the 8-10 weeks required, an unlikely task in almost any scenario.

Where however a low input approach is been adopted, the one application will give best response when applied during mid stem extension GS32-33, maximising Rhyncho control on the upper leaves. This is normally some weeks after the optimum timing for the herbicide application. Mid stem extension is too soon however to get reliable Ramularia control and unlikely to prevent a late infection of Rhyncho.

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.

Spring Oats

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

CAPALO and COMET 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

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 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.

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 only, as the flag leaf is emerging. The correct timing for treating spring oats is at 2nd node, GS32.

 

Good Weather Drives On Crops

The spell of glorious weather experienced over the last couple of weeks has made a huge difference with all of spring cereal crop now emerged and the early ones at mid tillering and beyond. 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.

Winter cereals for the most part are racing through the growth stages, while the majority look remarkably well, growth stages range hugely particularly in wheat, reflecting the extended sowing period throughout the autumn and winter months. Disease levels are variable with the more advanced crops showing higher levels of Rhynchosporium or Septoria.

Winter barley varies from awns appearing to heads fully out on the most advanced. Disease levels are generally low, with Rhyncho contained to the oldest leaves. However Ramularia is now appearing onto the upper leaves of some crops and this disease must be robustly controlled at the T2 timing along with Rhyncho, Net Blotch and Mildew.

 

 

Winter wheat crops range from those at 3rd node to flag leaf fully out. Septoria lingers on the lower leaves of all crops, and is rapidly moving up onto new growth in some. Yellow Rust has been found in recent weeks and surprisingly appearing in the variety Graham.

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).

Managing disease resistance and maintaining reliable control with the fungicide options available means using a range of different actives over the course of the growing season. 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 essential partners to protect the triazoles and maximise the yield in all but the most backward crops, adding some 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 disease strains controlled. It is good practise to use different actives from within the same chemical group at the different spray timings. Where possible, use different triazoles and SDHIs at each fungicide application over the course of the season to give the widest possible activity across the different strains of fungi of all diseases.

 
Page 1 of 21123...Last »

Recent Crop Crack

  • Thoughts Turn Towards Harvest

    All winter barley crops are looking well and the gates are now closed until desiccation pre-harvest. Most winter wheat crops have received their T3 earwash with a few later…

  • Dry Weather Challenging For Young Crops

    Most crops continue to benefit from the recent hot weather with many racing through the early stem elongation stages in a matter of days. However the late planting in…

  • Good Weather Drives On Crops

    The spell of glorious weather experienced over the last couple of weeks has made a huge difference with all of spring cereal crop now emerged and the early ones…

Recent News