Ascochyta blight is a fungal disease caused by Phoma rabiei (formerly known as Ascochyta rabiei). While one type of ascochyta blight is established in Australia it is limited to asexual reproduction unless a second mating type (required for sexual reproduction) also establishes here.
Sexual reproduction of the fungus would allow it to develop resistance to fungicides far more rapidly as well as get around the defences of chickpea varieties bred to tolerate the blight
Symptoms differ depending on whether ascochyta blight is introduced to a paddock through infected seed or through airborne spores known as conidia from nearby infected plants. Infected seeds result in early plant death whereas infection from airborne conidia often develops symptoms later in the season. Small patches of blighted plants will appear through a crop, spreading into larger patches with cool, wet weather as rain splashes spread the spores further.
The asexual phase of ascochyta blight produces distinct dark fruiting bodies (pycnidia) which contain and release the conidia. Pycnidia are arranged in concentric circles that occur in the centre of lesions found on infected leaves, stems, pods and ultimately developing seed. Severe stem lesions can lead to girdling which can kill the upper part of the plant or result in stem breakage.
The sexual stage, not known to occur in Australia, uses chickpea stubble as a host, producing a different type of fruiting body and spores which could go unnoticed unless stubble is checked.
Report any unusual outbreaks of chickpea ascochyta blight, especially if they occur on known resistant varieties.
Protect your farm from exotic plant pests by checking crops frequently. Make sure you are familiar with the symptoms of common plant pests and diseases so you can tell if you see something different.
If you suspect soil borne diseases or nematodes in your chickpea crops, limit movement into and out of affected paddocks.
Protect your farm from exotic plant pests by checking crops frequently. Make sure you are familiar with the symptoms of common plant pests and diseases so you can tell if you see something different.
If you suspect soil borne diseases or nematodes in your chickpea crops, limit movement into and out of affected paddocks.