The choices you make when growing a barley crop can have a significant effect on what disease management is going to be needed.

The variety should be chosen carefully, looking at the main agronomic characteristics, taking note of its weaknesses in disease resistance ratings, straw and lodging.

This is not always possible for malting barley growers as variety choice is restricted, but it highlights the need to have a good understanding of the variety being sown and what challenges might occur.

Application timing

High yields in barley are achieved by high grain numbers per m2.

To achieve this, good early season disease control is essential to protect tillers to help produce high-yielding crops.

Extensive research has been carried out on both winter and spring barley, looking at optimum timing for fungicide applications. In spring barley, four possible timings were looked at, late tillering (

The key timings were found to be late tillering (

In winter barley, five possible timings were included in the experiments. In addition to the timings used on spring barley, an autumn application was included; again all possible combinations were used.

The key timings to maximise the response from fungicides was found to be a three-spray programme including late tillering (

Product choice and rate

There is a large selection of chemistry to choose from, from solo products to three-way mixes. Research carried out at Oak Park found that the key to using the chemistry successfully in a spray programme is through the use of mixtures of actives that complement each other at each timing. This also helps as part of an anti-resistance strategy, by reducing the overreliance on any one product/active.

The product choice and rate should reflect the level of disease risk present, based on variety, disease levels and weather pattern.

There should be a minimum of two actives (azoles, SDHIs, strobilurins and multisite) in the tank at each timing; an additional mildewicide may also be included, where required.

The addition of Chlorothalonil at the later timing is a must for Ramularia control in both winter and spring barley.

The decision on what rate to apply is always a topical issue, as fungicides are considered an insurance policy. Over the last number of years, a large number have experiments have been conducted to try to tackle this issue.

From the experiments carried out, the optimum rate of application for both winter and spring barley is approximately a half rate of each mix partner.

One of these experiments looked at three varieties of spring barley with increasing resistance rating to Rhynchosporium ranging from a four to a seven on the rating scale, over six site seasons. The trial found that there was no economic benefit from going above a half rate (Figure 1.).

For both winter and spring barley fungicide programmes, the spend should be spread equally across the timings.

At Crops & Cultivation, experiments showing a range of spring barley disease programmes will be on show, with a number of standard fungicide programmes at different dose levels, from quarter-rate programmes up to full-rate programmes, to help identify the optimum rates to use.

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Focus supplement: Crops and cultivation