Management of disease in chickpea
Ascochyta blight
(causal fungus: Ascochyta rabiei, also known as Phoma rabiei)
Industry note: Ascochyta blight is a serious disease of chickpeas. Complacency about Ascochyta is a significant threat to the northern region chickpea industry. It is vitally important for the industry to follow protocols for managing Ascochyta blight.
Symptoms of early Ascochyta blight infection are often very difficult to detect, because they tend to be in the lower plant canopy.
There can be a strong temptation to back off in both seed treatment and program spraying, and adopt a wait-and-see approach.
This approach should be avoided, because:
- several successive winter growing seasons of dry weather usually results in low levels of Ascochyta blight in chickpea crops, which can lead to complacency in years of good rainfall, when the risk from the disease is much greater
- the consequences of adopting a wait-and-see approach can result in higher levels of the disease, requiring multiple fungicide applications and even the possibility of crop failure under wet conditions
- it is critical that we stay on top of the Ascochyta problem in this region and that we continue preventative disease management strategies as developed in consultation with the industry.
Key points preventing Ascochyta
- Implement the Ascochyta management strategy appropriate for each variety, your region and the paddock’s risk situation (high, medium or low).
- If high levels of Ascochyta infection have been observed on volunteer chickpea plants over the summer fallow period, avoid planting adjacent to, or near last year’s chickpea ground. Use a registered herbicide to kill chickpea volunteers.
- Sow within the optimum planting window for your district. Consider deep planting (moisture seeking) provide you have high-germination, high-vigour seed. Sowing rates will need to be increased when moisture seeking.
- Always sow seed treated with a thiram-based fungicide. Growers in coastal and central Queensland are urged to use seed sourced from crops grown in central Queensland.
- Assess whether row-cropping configurations and band-spraying of fungicide/insecticides is practical.
- Assess your capability to implement early harvest management. Understand the correct growth stage for application of desiccants.
The information above is based on current knowledge and understanding. However, because of advances in knowledge, growers are reminded to ensure that information they rely on is up-to-date and to consult with their local Department of Employment, Economic Development and Innovation (DEEDI) or private agronomist.
Ascochyta Blight, a serious fungal disease
Three levels of Ascochyta risk in the northern region
Low-risk areas (Central Queensland)
Ascochyta has now been detected in Central Queensland (Highlands) as well as in the Dawson-Callide valleys, but has not been found in coastal Queensland regions. The seasonal weather conditions in Central Queensland are considered to be not as conducive to Ascochyta blight development as conditions in southern Queensland. Please check protocols for managing an outbreak and check on media reports and this webpage for updates.
Medium-risk areas
Most chickpea crops grown in southern Queensland and northern New South Wales are considered to be in the medium-risk category. Chickpea crops in this zone are expected to contain some level of Ascochyta, which could result in serious economic losses if not effectively managed.
High-risk situations
The crop is considered to be at high risk of Ascochyta infection if:
- susceptible and very susceptible varieties (see table in step 4 below) are being grown
- planting in close proximity, or adjacent to last year’s chickpea paddocks
- where the preventative management strategies have not been followed (i.e. using untreated seed of unknown disease status).
In these situations the control measures should be strictly followed. The major change in the fungicide recommendations is that chlorothalonil will often be required much earlier in the spray schedule, particularly during showery, wet conditions.
