Blackspot disease control is central to disease management and maintaining yield potential in field pea. by Alan Meldrum, Pulse Australia industry development manager
Don’t sow field pea too early
Blackspot control in field peas is critical to avoid yield losses. Careful paddock selection to avoid a recent history of field pea is important to minimise the risk of blackspot spores from old stubbles reaching a newly emerged field pea crop. Delaying sowing until after spores from the previous season have been released and rendered ineffective is the next most important decision.
The Department of Agriculture and Food (DAFWA) ‘Field pea blackspot sowing guide for Western Australia’ provides the latest sowing guide for locations in WA. The sowing guide is based on recommendations from the very robust ‘DAFWA Blackspot Model’ and provides a best bet guide to the safest time to plant field pea in various localities. Sowing before the forecast indicates it is ‘safe’ to do so is likely to lead to higher disease pressure and consequently poorer crop yield.
Conditions in 2015 appear to be following a similar path to those that occurred in 2013 in Esperance. Good soil moisture early in the season enabled growers to sow crops early, finishing their programs with field pea but before it was safe to do so. The result was a high level of blackspot disease and the resulting yields were only half what was expected, leaving many growers very disappointed.
In 2015, this same scenario is possible. April rain has had growers planting canola, beans and lupins early before moving into wheat. Growers may be ready to consider planting field pea soon, but in some of the key field pea growing districts the blackspot sowing guide is indicating that the blackspot risk is still too high, up to the week of 19 May, 2015.
Blackspot disease occurs when the spores from stubble material are released after a period of rain and low temperature, and land onto emerged field pea. If the spores land onto bare soil, they cause no harm. The aim of the model is to forecast when the spore release has happened in each district, such that the spore release occurs before field pea has germinated.
This year, as in 2013, the early rainfall has not coincided with a sharp drop in temperature, meaning that there has not been a significant spore release. Delaying the completion of seeding for 2015 is a small price to pay for a healthy field pea crop.
Discuss your specific situation with your advisor or agronomist and visit the DAFWA website to check the sowing guide https://www.agric.wa.gov.au/crops/grains/pulses/field-peas
For more detailed information refer to ‘Field pea disease management: Southern and Western Region’
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Originally published May 2015