April is the month when winter barley crops develop fastest and demand for plant nutrition is highest.
Depending on the total amount of nitrogen (N) to be used, growers should make sure to apply the last division before Growth Stage (GS) 32, Teagasc advises.
Barley crops do not use late N efficiently. To maximize returns, N must be running before the flag leaf is visible. Manganese deficiency is also quite common in barley crops and requires attention.
Where disease Control As far as Teagasc is concerned, he reports that the decision to use a two or three spray strategy will depend on variety and location.
Growers should use a three-spray schedule on susceptible varieties (eg, cassia) or where disease levels are moderate or high. This is especially so in the southern half of the country.
However, with crops in the northern half of the country using clean varieties, growers can get away with two applications.
A suggested spray plan follows: First spray: GS30; second spray – GS31 to 33; and third spray – GS39 to 49.
Fungicides that can be used include: Siltra at 0.6 l/ha; lure cups; Elatus Era at 0.8 l/ha; MacFare Xpro or Proline at 0.4 L/h plus SDHI or strobilurin (Imtrex, Zulu, etc.)
When mold is evident, a mold repellent should be used. Additionally, Folpet can be added to the last spray for ramularia control.
Plant growth regulator for winter barley and crops.
Growers should try to apply a plant growth regulator (PGR) on two-row varieties between GS32 and GS37 to achieve effective shortening.
Products that can be used in this context include Terpal at 1.2-1.5 l/ha, Cerone at 0.5-0.7 l/ha and Meddax Max at 0.3-0.5 kg/ha.
For six-row varieties or two-row varieties on very fertile sites, two applications are usually required.
Growers should consider a mix of Moddus at 0.2 l/ha plus Chlormequat Chloride (CCC) at 1.0 l/ha around GS30 or 31. This would be repeated at the normal time in GS32-37.
Growers need to be very weather-aware when applying PGRs.
Frost will decrease the effect of products, while increasing the chance of burning. Growers should also avoid complicated mixes, as crops can be prone to burning at this time of year.
Meanwhile, in Northern Ireland, advisers from the College of Agriculture, Food and Rural Enterprise (CAFRE) are confirming high levels of downy mildew and rhynchosporium infection in some advanced winter barley crops.
The advice here is to keep fungicide rates high, particularly if a T0 fungicide was not applied or T1 has not yet been applied.
