Crop Watch August 2021

Get your pulse fungicides ready for spraying

Current weather conditions are ideal for infection with botrytis and sclerotinia diseases in pulse crops, particularly lentil, faba bean, canola and lupin. The wet weather is providing damp conditions in soils and crop canopies.

Sclerotinia develops rapidly in wet conditions irrespective of the temperature. Botrytis grey mould (BGM) and chocolate spot diseases develop rapidly in wet conditions when the air temperature is above 15°C. Continuous wet conditions will also allow BGM and chocolate spot to slowly develop even at temperatures lower than 15°C.

Growers should be prepared for foliar fungicide sprays in their pulse crops leading up to canopy closure and then continue to monitor conditions for additional sprays during spring.

If rain continues during spring and or the crop canopy remains damp, then these diseases will remain a threat. Additional fungicide sprays may be required after canopy closure 2-3 weeks apart depending on weather conditions.

Most of the fungicides registered for these crops and diseases can only be sprayed twice into a crop, however, a number of fungicides are registered for this purpose including carbendazim, procymidone, AviatorXpro®, Miravis Star®, and Veritas®. This provides the opportunity to rotate different chemistries to protect against disease and this rotation also reduces the risk of fungicide resistance.

Keep sending your crop disease samples

SARDI is seeking diseased samples from this year’s commercial pulse, canola, barley and oat crops. The samples will assist research scientists Sara Blake and Tara Garrard with monitoring the nature and extent of disease in 2021.

Grain growers and advisers are being asked to help in providing samples of:

• ascochyta blight in lentil, faba bean and chickpea
• Sclerotinia in pulse and canola crops
• net form net blotch and scald in barley
• Septoria in oats.

These samples will contribute to GRDC project investments that screen for any changes in ascochyta blight disease resistance of current cultivars, to monitor pathogen population changes and to also understand how serious a disease sclerotinia is for the southern pulse industry.

The barley disease samples will contribute to a national GRDC survey pathotyping key barley foliar pathogens to monitor pathogen population changes and to screen for any disease resistance changes.

Oat Septoria samples will contribute to a GRDC project identifying novel sources of oat Septoria resistance and understanding the virulence of the pathogen.

Collection kits with return envelopes will be provided to growers and advisers willing to provide samples.

For ascochyta and sclerotinia in pulses and canola, please contact:

Sara Blake
Phone: (08) 8429 2248
Email: sara.blake@sa.gov.au

For net form net blotch and scald in barley, and Septoria in oats, please contact:

Tara Garrard
Phone: (08) 8429 2247
Email: tara.garrard@sa.gov.au

Monitor your cereal crops for wheat stripe rust now

Wheat stripe rust in the Victorian Wimmera near Stawell has been reported in a crop of Trojan. This is the first report of stripe rust this season and is cause for concern given how early in the season the disease has been reported.

Wet winter conditions across the state have allowed crops to establish well after the late opening rains but will also make crops prone to stripe rust as temperatures begin to rise.

The disease can develop rapidly in susceptible cultivars in temperature conditions of 8-15°C. Stripe rust spores can travel long distances in the wind and growers are encouraged to monitor their paddocks, particularly in the South East near the Victorian border.

Please get in touch with the SARDI Cereal Pathology team if you encounter stripe rust in your paddock.

To check the disease resistance rating for your varieties, go to the Cereal Variety Disease Guide 2021 (PDF 464.8 KB).

Need some support on how to manage stripe rust?

If you'd like further decision support, the StripeRustWM app is available from Apple and Google Play stores.

StripeRustWM uses a forecasting model to assist wheat growers with fungicide application decisions and generate predictions on economic returns from those decisions.