Loose Smut in Barley Update

Why was there so much loose smut around in barley crops again this year?

Loose smut in barley is internally seed borne so if you are seeing infected heads then it means your grain source was contaminated. It is the hardest of the smut diseases to control because it is an internally seed-borne infection and most current seed treatments are not fully effective on internally seed borne diseases.

But I used a seed treatment!Due to the lifecycle of loose smut, a fungicidal seed treatment that penetrates the seed at germination is required to control the disease. Most smut diseases can be controlled by a seed treatment that sterilises the surface of the seed but this is not the case for loose smut as the fungus is within the seed.

Excellent seed treatment coverage of every seed is also required to ensure control. Even with a highly effective seed treatment such as EverGol Prime, control will be reduced if seed treatment coverage is poor.

Disease lifecycle:Barley crops infected with loose smut will have the characteristic dark spore fi lled heads within the crop which is actually the appearance of infection from the previous season which has been within the seed. At maturity, the spores will rupture and be spread by wind infecting neighbouring crops at fl owering. Moist conditions at fl owering combined with mild temperatures will favour infection. Grain infected this season will appear completely normal. When the seed is sown and germination occurs the following season, the fungus will begin to grow within the plant with a mass of spores replacing the head and continuing the disease cycle.

In this update article we cover the lifecycle of loose smut in barley and how Bayer’s recently registered seed treatment EverGol® Prime can help provide more effective management of this disease next season. EverGol Prime sets a new benchmark for loose smut control in barley. EverGol Prime is registered for the suppression of rhizoctonia root rot and for the control of smut diseases* in wheat and barley.

Diagram 1 source: Lifecycle adapted from McMullen and Lamey (2000). Seed Treatment for Disease Control, NDSU.

Loose smut.

Diagram 1: Lifecycle of loose smut in barley and wheat.

Diagram 1 source: Lifecycle adapted from Seed Treatment

LooseSmutLooseSmut

Impacts:

As the disease affects all tillers of plants grown from infected seed, if the incidence of disease is high within a crop it will result in signifi cant yield loss as no grain will form from an infected plant. Additionally, when grain is delivered to receival points, it is assessed for the presence of loose smut. According to Grain Trade Australia trading standards, if the level of spores per half litre of grain is high, the whole grain load may be rejected.

Options for disease control:Due to the ability of EverGol Prime to penetrate the seed at germination, it offers exceptional control of this disease.

Trial data in Graph 1 from two trials conducted during the 2013 season shows how effective EverGol Prime is at registered rates compared to other seed treatments for loose smut control in Hindmarsh barley. Graph 2 shows further trial data for loose smut control in barley.

EverGol Prime gives outstanding control of barley loose smut beyond many other seed treatments currently in the market place.

Loose Smut in Barley Update

www.bayercropscience.com.auBayer CropScience Pty Ltd, 391–393 Tooronga Road, Hawthorn East, Vic 3123.ABN 87 000 226 022. Technical enquiries 1800 804 479.EverGol®, Baytan® and Raxil® are Registered Trademarks of the Bayer Group.Seedgrowth™ is a trademark of the Bayer Group.

December 2013

Graph 1: Loose smut control in Hindmarsh barley (% utc inf) WA trials 2013 (13WE04 & 05)

EverGol Prime80 mL

EverGol Prime40 mL

Baytan® T100 mL

Vibrance®

180 mLTri-Power®

400 mL

30

50

40

60

70

80

All rates per 100 kg of seed.

All rates per 100 kg of seed.

90

100

Graph 2: Barley Loose Smut Control (Average of 2 Trials *WA31 *NW23)

EverGol Prime80 mL

Raxil® T100 mL

Baytan T100 mL

Dividend®

130 mL

30

50

40

60

70

80

90

100

% c

ontro

l%

con

trol

Regans Ford (WE05 - 4%) West Wubin (WE04 - 2.8%)