The rising temperatures over the last week have been very welcome for all crops but unfortunately awns have begun to appear on winter barley with critical plant growth regulator missed. Mildew is present on almost all winter cereal crops and should be treated at T2 timing. In spring barley & spring wheat an early application of ADJUST increases root development and the numbers of surviving tillers which will improve crop establishment and yield. Because of the spring crops more rapid progression through the growth stages than the winter crop, 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.
Leatherjacket numbers are considerably higher this year with widespread damage to grass swards particularly in the west of the Province. Damage is now becoming evident in some of the earlier drilled cereals. Feeding activity and therefore the likelihood of damage will increase as soils continue to warm. Crops most at risk are those drilled into old ley or dirty stubble, but monitor all emerging crops closely for signs of damage. The grubs will be quite easy to find in areas of poor emergence, when the soil is dug down to a depth of 4-5cm.
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,Oxytril Cm and Spitfire. Each of these partner options are very tank mixable, and other products such as ADJUST 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.
All winter barley crops have now received their T1 fungicide, with the T2 planned for the coming weeks. Prothioconazole in (MOBIUS or SILTRA) or epoxiconazole in (MANTRA or ADEXAR) at this critical timing will give maximum benefit over straight triazole products. Mildew levels are extremely high and thereforeTALIUS should be added.
Like the winter barley, the mild winter means Septoria and Mildew levels are higher than seen at the same time in recent years. Yellow Rust has also been found in some earlier sown crops and the threat will remain high. Robigus and Einstein have both broken down to new races of this disease and are more susceptible than ever. Like the barley, the T2 application should now be planned as recently applied fertiliser coupled with warmer temperatures will push crops through the growth stages very quickly.
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 this week’s 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.
SHOGUN has a full recommendation for scutch control on ware potatoes. It will also give excellent control of perennial ryegrass, wild oats and volunteer cereals. If the crop is under drought or temperature stress when sprayed, transient yellowing may occur. For this reason its use is not approved on seed crops since these symptoms could be confused with viral disease.
Grass and weeds have been under stress up to now and where silage is still some weeks away there is an opportunity to apply herbicide.