A novel seed treatment could contain the ravages of anthracnose, which wiped out Western Australia’s 80,000 hectare albus lupin industry after its arrival in 1996.

Interestingly, however, holding seed at 60° C to 70° C for four to five days before seeding can reduce seed infection without diminishing viability or germination.

Anthracnose is a seed-borne disease which spreads when spores from infected crops or stubble are carried to new hosts by rain droplets or spray. Seeds with low infection levels, therefore, are valuable to help restrict the spread of the disease. Heating seed could emerge as a quarantine requirement for the movement of lupin seed between states and internationally to reduce anthracnose proliferation.

According to Geoff Thomas of the Western Australian Department of Agriculture, who investigated anthracnose management with support from growers and the Federal Government via the Grains Research & Development Corporation (GRDC), seed infection rates as low as 0.02 per cent can erupt into an epidemic, robbing growers in high rainfall zones of more than 10 per cent in yields

Because rain aids anthracnose spread, growers must try to match variety with the annual rainfall in their area. Susceptible varieties, such as Quilinock, Wodjil and Kiev Mutant, risk yield losses if exposed to high moisture seasons, even with low initial seed infection rates. Growers from wetter areas, such as the northern agricultural zone, should look more to resistant varieties such as Tanjil or Wonga.

The GRDC project also found that contact and systematic foliar fungicide applications helped cut infection and protect yields in glasshouse and field trials. However, timing was crucial and spraying should occur no more than four days before rainfall (when infection events occur).

Using more resistant varieties was more economical, but where not an option, such as with highly resistant varieties grown under intense disease pressure, or where soil types limited grower choice to highly susceptible varieties, responses to foliar fungicides were encouraging.

Mr Thomas believes industry interest may prompt the Department to use these results to support an application to register foliar fungicides for anthracnose control.

Between these investigations and discovering that heat management could help reinforce future quarantine efforts, this GRDC project demonstrated a clear future for anthracnose management.