Be prepared and avoid the spot

Views

Spot Form of Net Blotch (SFNB) is a barley foliar disease that thrives in early sown crops, susceptible varieties, in conditions where stubble is retained and when climatic conditions are cool and wet, which mirror current seasonal conditions.

Conducive conditions in 2016 saw a spike in SFNB levels and subsequent crop damage which was most evident in susceptible varieties La Trobe, Hindmarsh, Rosalind and Spartacus.

Over the past few years, BCG has worked with Agriculture Victoria to investigate the management of SFNB. The past two seasons have focused this work on effectiveness of seed applied fungicide Systiva® (fluxapyroxad), and foliar applied fungicides Prosaro® (prothioconazole/tebuconazole) and propiconazole for SFNB suppression and yield advances. Different timings and growth stage treatments where used in Rosalind barley when testing the foliar applied fungicides.

Research results from 2014 into the impact of SFNB on varieties highlighted that SFNB can cause up to 11 per cent yield loss in very susceptible varieties and reduced grain plumpness.

In contrast, 2015 found no benefit to SFNB management from using Systiva®, or foliar applications of propiconazole or Prosaro®, with seasonal conditions not being conducive to heavy disease development, and use of management strategies not offering yield or financial benefit.

In 2016, under exceptional growing conditions, SFNB caused up to 20 per cent (1.1 t/ha) grain yield loss, but there was no grain quality loss.

Effective suppression of SFNB and significant increases in grain yield were seen (Figure 1) in treatments where seed had been treated with Systiva®, or propiconazole or Prosaro® were used at two timings, GS31 (first node) and GS39 (flag emergence).

SFNB Mark McClean article 2016

 

 

 

 

 

 

 

 

Figure 1. SFNB severity (% leaf area affected) at ripening (GS85) and grain yield of Rosalind in response to fungicide treatments at Curyo in 2016.

Systiva® offers effective management for a large part of the season however with sowing nearing completion the emphasis may now be back on foliar fungicide applications. Making sure that effective and timely foliar sprays are used are the key to minimising yield loss from SFNB. Whether you choose to use propiconazole or Prosaro®, performance on SFNB does not appear to be that different from the work carried out but the costs may be.

Growers should assess fungicide requirements based on yield potential and seasonal conditions. For crops with average to above average (>2.5t/ha) yield potential, the best strategy for managing SFNB in-season is an application of fungicide at GS31 and GS39. Members can access the full trial report on the website: Effective SFNB management using fungicides during a wet Mallee season.

Upcoming Events

Become a BCG Member

BCG exists for its members. Research and extension activities are designed to provide members with information and resources that will help them improve the productivity, profitability and sustainability of their farm businesses.

Improve your profitability

Receive the latest research, extension and event news direct to your inbox! For a limited time, receive a free technical bulletin when you subscribe.