G1 Blackspot Manager model predicts the maturity and release of ascospores in relation to ascochyta blight on field pea

Combining management and breeding advances to improve field pea (Pisum sativum L.) grain yields under changing climatic conditions in south-eastern Australia

“…Investigation of flowering period showed that this genotype has earlier and longer flowering period than Kaspa, making it less susceptible to yield loss when sowing is delayed in short growing seasons. This early flowering germplasm combined with sufficient disease resistance to ascochyta blight may provide growers with the flexibility to either sow earlier using current disease management strategies or sow later if high disease risk is predicted through disease modelling (Salam et al 2011).…”

“…However forecasting of ascochyta blight risk (Salam et al 2011) will enable growers to make informed decisions with respect to sowing date and the need for strategic fungicides to control this disease. Furthermore fungicide applications appear more viable on the earlier flowering germplasm such as OZP0602 but need to be considered on the basis of predicted ascochyta disease, yield potential early in the growing season and likely value of the grain at harvest.…”

G2 Blackspot Manager model to guide field pea sowing for southern Australia in relation to ascochyta blight disease

“…This model (G1), a weather-based system, constructed by synthesising knowledge generated in the field of epidemiology of ascochyta blight on field pea, reliably predicts the temporal dynamics of seasonal ascospore release from infected stubble (Salam et al 2011b). It may be re-stated that the epidemics of this disease in southern Australia are primarily initiated by airborne ascospores released from the matured pseudothecia that develop on the infected field pea stubble from the previous year (Bretag 1991).…”

“…Pseudothecia on infected stubble release a succession of ascospores over a period of several months. This mechanism has been captured in the model by using the cumulative Beta distribution function to describe the relationship between the cumulative number of mature ascospores (CNMS) and total FPM days (described in detail by Salam et al 2011b). Ascospores are presumed to be discharged in discrete daily events on or after the onset of pseudothecial maturity, when daily rainfall meets or exceeds a threshold value.…”

“…Thus, the principal disease management strategy advocates delay the sowing as far as possible towards the end of the sowing window to avoid the majority of ascospores falling on the emerging field pea seedlings (Bretag et al 2000;McMurray et al 2011). Recently, a reliable weather-based system, the G1 Blackspot Manager model, has been developed to forecast the temporal dynamics of seasonal ascospore release in order to formulate a safer sowing times of field pea in southern Australia (Salam et al 2011b). This model predicts, based on pre-seasonal daily temperature and rainfall, the quantified amounts of ascospores a field pea crop is exposed to when sown on a given date at a given location.…”