New ascochyta and botrytis grey mould advice for 2016 for chickpeas

Take home message

• Guidelines for managing Ascochyta and Botrytis in 2016 have been revised as a result of changes to predicted winter and spring rainfall.
• Growers are advised to take a conservative approach to Ascochyta management and use an integrated management strategy of agronomy and fungicide application in Northern Region chickpea crops (with the exception of Central Queensland).
• Have at least 2-3 Ascochyta and 1-2 Botrytis fungicides on farm.
• In most situations, apply an Ascochyta fungicide to ALL varieties (including PBA HatTrick and PBA Boundary) BEFORE the first post-emergent rain event.
• Be prepared to apply a BGM fungicide in early-mid September

Changes to the 2016 winter crop weather 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 (AB) 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 foliar 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.  Planting deeper will prolong emergence and achieve a similar result to delaying planting.

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 will 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, but 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 BGM fungicide. Consult your agronomist as to whether to apply a second BGM spray.

Acknowledgements

This research is made possible by the significant contributions of growers through both trial cooperation, paddocks access and the support of the GRDC, the authors would like to thank them for their continued support. 

Contact details

Kevin Moore
Department of Primary Industries, Tamworth, NSW
Ph: 02 6763 1133
Mb: 0488 251 866
Fx: 02 6763 1100
Email: kevin.moore@dpi.nsw.gov.au

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