chickpEa disEasE managEmEnT FACT SHEET - Grains Research ...

Figure 1. The concentric circles ofbrown-black dots in the centre of the leaflesions are known as pycnidia. Thesefruiting bodies are unique to ascochytablight and are useful in identifying thedisease. Leaf death may also be causedby frost or herbicide injury but in thosecases, there will be no pycnidia present.It can be seed-borne, attacking theseedling during emergence and causingrot on the upper taproot and collar.Affected areas develop a soft rot anda fluffy grey mould (See Figure 3).Significant losses can occur in wet springsin crops with dense canopies.Use seed from disease-free crops for sowing;apply a seed dressing and foliar fungicides.Fungicides such as chlorothalonil ormancozeb for ascochyta blight can givesome protection against BGM, dependingon the timing of application.However applying a product, such ascarbendazim, that specifically targets BGMduring flowering to protect flowers andsubsequent pods will be more effective.SclerotiniaSclerotinia (S. sclerotiorum and S. minor) cancause significant crop losses in chickpeas ineastern Australia, but it is sporadic.Photo: Gordon CummingFigure 2. Round, sunken lesions indicatingascochyta blight infection on chickpeapods later in the season. The funguspenetrates the pod wall and infects theseed, resulting in reduced seed set anddiscoloured seed.The disease is readily identified as whitemycelial growth on infected plant tissue,which later produces small, black survivalbodies called sclerotia (See Figures 4 and 5).It is favoured by cool, wet conditions inwinter and spring, and may first appear ifthere are very wet conditions in July.Control by using disease-free seed and byrotating with cereals and other non-host crops.Fungal disease managementOn-farm hygieneAB and BGM carry over from one seasonto the next on infected stubble, seed oron volunteers. Control volunteers preseedingto limit build-up of diseaseinoculum for the new crop.It is a good idea to reduce stubble(chop, bury, destroy, graze or burn infectedcrop residue) where it will not create anerosion risk.Photo: DPI VictoriaPaddock selectionDo not sow adjacent to old chickpea stubble,particularly downwind, and aim to separateby a distance of at least 500 metres.A break of at least four years betweenchickpea crops will minimise soil inoculum.Herbicide residues may increasesusceptibility to disease. Observe themaximum plant-back period for:sulfonylurea;imidazolinone;pyridine;phenoxy;benzoic;quinoline; andtriazine.Note that plant-back periods for someherbicides have a rainfall requirement. Forexample, for OnDuty ® (Group B), the plantbackperiod requires 150 to 200 millimetresof rain over 10 months. For 2,4-D Ester(Group I), the plant-back period (dependingon rate applied) is 14 days following at least15mm of rain in a single event.Paddocks with low soil fertility or nutrientstatus can lead to stress, predisposingchickpeas to disease.VarietiesYield and marketability, along with diseaseresistance, are the major factors toconsider in variety choice (See Table 1).Seed for sowingUse seed of the highest possible purity,germination and disease-free status.Photo: kevin moorePhoto: kevin moorePhoto: DPI VictoriaFigure 3. Botrytis cinerea producesdiffuse, whitish fungal growth which thenturns grey due to the production of hugenumbers of spores born in clusters atthe ends of dark stalks. Free moisture isnecessary for germination and infectionof botrytis grey mould.Figure 4. Sclerotinia is identified as whitemycelial growth on infected plant tissue,which later produces small, black survivalbodies called sclerotia. When thesesclerotia germinate in the soil they releaseairborne spores that infect above-groundparts of the chickpea plant, often startingin leaf axils.page 2Figure 5. Fungal weft of sclerotinia inthe lower canopy of a chickpea crop.The disease produces a white mycelialgrowth, like cottonwool, that covers theinfected tissue.