Ascochyta blight spotted in chickpeas
- Mingenew region
Researchers from the Centre for Crop and Disease Management (CCDM) spotted some ascochyta blight in chickpea varieties Genesis836 and Neelam in the Mingenew region as they travelled across WA’s Midwest region recently.
Ascochyta blight is caused by the fungus Ascochyta rabiei (now referred to in some literature as Phoma rabiei) and it is a serious disease of chickpeas in Australia.
Initial crop infection is due to the introduction of either infected planting seed or from movement of infected plant material by wind, machinery or animals. The spores of ascochyta can adhere to clothing, machinery, vehicles, people and animals when moving through infected paddocks, so hygiene is a vital component of management when ascochyta is found in a crop.
Subsequent in-crop infection and spread occurs when inoculum is moved higher in the canopy or to surrounding plants by wind or rain splash during wet weather. There are no other known hosts of Phoma rabiei in Australia.
Ascochyta blight can be identified by lesions or dead areas which develop on the stems, leaves and pods of the chickpea plant. Symptoms of diseased plants are stem breakage or young growth drooping over. Inspection of these areas will show elliptical brown lesions on the stem, some of these will contain black fungal fruiting bodies (pycnidia). Whole plants can be killed and patches of dead and diseased plants develop in the crop. Patches may vary from 1-15m in diameter.
Ascochyta blight is managed through crop rotation, hygiene, seed treatment, prophylactic fungicide application and growing varieties with improved resistance. Plant pathologist Jean Galloway (DPIRD) says that in the eastern states, a virulent strain of ascochyta rabiei has overcome this resistance. In WA, this virulent strain has not yet been detected, however strains have been found that can cause high disease in HatRick and Genesis 090.
All growers and advisors are being urged to inspect their chickpea crops regularly, from emergence through flowering right up to plant maturity. Inspections should be undertaken 10–14 days after rain events, when new infections will be clearly evident as lesions on plant parts. If any ascochyta blight is found in HatRick or Genesis 090 then these varieties should be sprayed, do not rely on resistance ratings. For other varieties, if the disease levels seem to be higher than expected based on their resistance rating then these should also be sprayed.
Differing spray programs have been developed based on each chickpea variety’s ascochyta rating. Chickpea ascochyta fungicides should be applied before rain events. The key to a successful ascochyta spray program is regular monitoring combined with timely application of registered fungicides. A full list of fungicides is available at the Pulse Australia website
Growers are being urged to check their chickpea crops and if they spot any in their paddocks they can send samples to Jean Galloway at DPIRD Northam or to CCDM. If you have any questions for CCDM researchers, please don’t hesitate to get in touch via firstname.lastname@example.org . CCDM’s Canola and Pulse Diseases researchers are working hard to identify key pathogenicity factors in Ascochyta Blight and to find more information about their work click here.
For more information about ascochyta and how to manage this disease see Pulse Australia’s Chickpea: Ascochyta blight management bulletin and DPIRD’s Chickpea variety specific ascochyta management, Mingenew 2016 trial report page.
For more information contact Jean Galloway, Plant pathologist, Northam on +61 (0)8 9690 2172.
Article authors; Jean Galloway (DPIRD Northam) and Cindy Webster (DPIRD Narrogin).
Article input by: Carole Kerr (CCDM).