Spring barley crops face high disease pressure after a wet spring

After a challenging drilling season for many spring barley growers, the need to respond to the likely impacts the wet conditions will also have on disease pressure have never been more important.

Rhynchosporium and net blotch are well established as the key wet weather diseases in barley, and we can anticipate a higher pressure this year as a result.

Low disease pressure in recent years

It is important however, to place high pressure years in context. In the last 10 years, the national spring barley crop has experienced low pressure from wet weather diseases like Rhynchosporium and net blotch, although this has varied in different areas of the UK. The table below details the number of Rhynchosporium scores reported in the AHDB harvest results over the last 10 years from across the entire UK RL spring barley trial network. The number of separate scores reported were relatively low in most years; only in 2014 did the number of records reach double figures.

	2013	2014	2015	2016	2017	2018	2019	2020	2021	2022
Rhynchosporium	6	16	7	5	7	1	5	0	1	4

Source: AHDB RL harvest results archive

Cultural risk factors

While the recent weather will undoubtedly increase the risk of wet weather diseases in all spring barley crops this year, it is worth being aware of additional cultural factors that also come into play too. Sowing date, variety choice and rotation are some of the key elements to consider here.

• Earlier drilled crops are expected to be at increased risk of disease. With the first spring barley crops being sown before Christmas and many only going in the ground recently, the range of drilling dates nationally is huge.
• Rotation has big implications for disease risk, as growing consecutive barley crops increases the risk of inoculum carryover, particularly important for Rhynchosporium and net blotch.
• Knowing the variety resistance ratings can help you to tailor your fungicide programmes accordingly and help achieve the full potential from the genetics.

Adapting fungicide programmes

Given the elevated risks of Rhynchosporium and net blotch this season, SYNGENTA strongly recommend that all growers review their fungicide programme with a BASIS qualified advisor to ensure it is still appropriate for their individual situation.

Trials have identified the T2 timing as having the biggest influence on yield in spring barley, but that there is still a yield benefit associated with using a 2-spray programme.

The following table contains the latest SYNGENTA fungicide guidance for spring barley, including a tailored 2-spray programme targeting Rhynchosporium and net blotch along with guidance for other situations. Ramularia, another key barley disease to control, should also be a target where risks are high. The expression of Ramularia is increased where crops are stressed so maintaining healthy crops overall will reduce yield loss from infection here too.

A wide range of drilling timings, a growing area of early sown crops and a wet spring may have created the perfect storm for disease this year, and there could be a need for growers to review their spring barley fungicide programmes. There are many good chemistry options available to control these diseases effectively in high pressure seasons, the likes of which we do not see every year.

Always consult a BASIS qualified advisor. Use plant protection products safely; always read the label and product information before use.