Recommended management for Ascochyta blight and Botrytis Grey Mould (BGM) in the Northern Region has been altered as a result of changes to predicted winter and spring rainfall. It is recommended that growers take a conservative approach to Ascochyta management and use an integrated disease management strategy of agronomy and fungicide application to combat increased risk and incidence of Ascochyta blight and BGM in Northern chickpea crops (with the exception of Central Queensland).
Changes to long term forecast
For the Northern Region the long term seasonal forecast has moved from predicted average early winter rainfall, and a probable El Niño, to above average winter rainfall combined with La Niña conditions in spring. This forecast, combined with evidence that the Ascochyta blight fungus is changing and concerns about varietal purity in the northern region, means chickpea growers will need to take a conservative approach to Ascochyta management. Mild, wet winter conditions will also produce high biomass crops and, combined with a wet spring, will favour Botrytis Grey Mould (BGM).
Reducing disease risk through agronomy
Delaying planting will reduce the number of disease cycles to which the crop is exposed, however this increases the risk that it may start raining and remain too wet to plant. In this situation, planting on wider rows (75cm or greater) will provide better aeration, delayed canopy closure and improved penetration and coverage by foliar fungicides.
Be prepared – have fungicides on farm
There is a high possibility of a global shortage of chlorothalonil and mancozeb fungicides in 2016. If possible, stocking 3-4 Ascochyta sprays in high Ascochyta risk areas and 2-3 sprays in lower risk areas on farm would protect growers from such a shortage. There will also be strong demand for BGM fungicides from the lentil industry and growers are advised to have 1-2 BGM sprays available on farm. In addition, Pulse Australia has already obtained Minor Use Permits for alternative Ascochyta fungicides.
Be proactive with Ascochyta fungicide application
In the 2016 season, growers may face a few different scenarios with regard to Ascochyta management.
Irrespective of whether Ascochyta was detected in 2014 or 2015 in your district, all varieties rated Susceptible (S) (e.g. Kyabra) or Moderately Susceptible (MS) (e.g. PBA Monarch) should be treated with a registered Ascochyta fungicide before the first post emergent rain event. Central Queensland growers should consult with their agronomist.
In the following situations, it is recommended that growers spray with a registered Ascochyta fungicide before the first post emergent rain event:
- If Ascochyta was found in your district in 2014 or 2015;
- If Ascochyta was found on volunteers over the 2015/16 summer;
- If you are uncertain of purity of your variety – purity of your variety is best determined by asking yourself: How confident am I that every plant in my crop of PBA HatTrick is a HatTrick plant?
- If Ascochyta was not detected in your district in 2014 or 2015 and was not found on volunteers over 2015/16 summer; however, you want to minimize your risk of Ascochyta.
If none of the above scenarios apply to your situation and you are prepared to accept some risk of Ascochyta, wait until Ascochyta is detected before activating a fungicide program. It should be noted that a lack of detection of Ascochyta in your crop or district does not mean it is not present. There have been several cases where Ascochyta was not detected in a previous crop, as was the case in 2014 and 2015, but became widespread on a subsequent crop or on volunteers.
Botrytis Grey Mould (BGM)
Unlike Ascochyta, if conditions favour BGM in 2016 it will occur irrespective of what has happened earlier in the season, including the use of Ascochyta fungicides. If the canopy is likely to close by mid to late September, apply a registered fungicide. Consult your agronomist as to whether to apply a second BGM spray.
Contact Kevin Moore (NSW DPI) – Mob: 0488 251 866, Fax: 02 6763 1100, Email: email@example.com
- Pulse Australia has a number of publications on Ascochyta blight in chickpea including symptoms, identification and management.
- Chickpea Ascochyta: latest research on variability and implications for management – 2016 GRDC Updates Paper
- The Northern Chickpea Ascochyta Diaries is updated throughout the season to inform growers of the current Ascochyta situation in New South Wales and Queensland.