Winter barley crops are looking really 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, 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 so 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 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 wetter’s to enhance its performance. The potassium salt in Roundup Energy is taken up significantly faster than isopropylamine salt; as a result Roundup 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, Resplend and Revus move into the leaf and redistribute throughout the leaf tissue as it increases in size whilst systemic products such as Consento, Fubol Gold 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.