27 February 2004: Pacific Seeds has warned farmers to follow useage recommendations “to the letter” if they plant its BLT 9 (sylvestris resistance) varieties of canola seed for the 2004 season.

Pacific Seeds supports the Canola Association of Australia (CAA) recommendations that the sylvestris resistance varieties should not be sown on the Eyre Peninsula or around Bordertown, in South Australia, this season, following outbreaks of blackleg in the previously highly blackleg-resistant sylvestris varieties.

Although blackleg severity in sylvestris-based crops in other canola regions last season was low, many plants had low levels of infection.

Pacific Seeds’ plant scientists believe stubble from infected plants may produce blackleg spores during 2004 that will infect the sylvestris-based varieties, and rate the risk of yield loss as very high.

Pacific Seeds Canola Business Manager David Strong said today that where growers chose to use the sylvestris-based varieties this year they should take all steps to reduce disease pressure from blackleg.

“Farmers using our BLT 9 varieties should follow the CAA recommendations to the letter, maintaining a minimum isolation distance of 500 metres from previous canola stubble and also destroying stubble,” Mr Strong said.

“We’re treating all our sylvestris-based varieties with Jockey® fungicide before sale this season, which will boost resistance but may not prevent yield loss.”

The sylvestris-based varieties are sold under the product names Hyola 43, Hyola 60, Surpass 400, Surpass 402CL, Surpass 404CL, Surpass 603CL and Surpass 501TT.

“Other varieties should not be affected and farmers should anticipate similar levels of blackleg infection in canola varieties with conventional resistance this season as in previous years,” Mr Strong said.

Pacific Seeds has participated in a recent round of workshops conducted by the Grains Research and Development Corporation and is briefing seed resellers, consultants and farmers about the blackleg risks.

It conducted a series of workshops in December in three states to alert the farming community to the breakdown of blackleg resistance to the previously resistant sylvestris-based varieties.

“The development of a new form of blackleg that has rendered the sylvestris-based varieties susceptible to blackleg is a great disappointment to us,” Mr Strong said.

“When they were first introduced four years ago the BLT 9 varieties were virtually immune to blackleg, leading to widespread adoption and substantially reduced yield losses from blackleg.

“This put strong selection pressure on blackleg, which responded with a new, more virulent strain which appears to be progressively attacking sylvestris-based varieties and rendering them very susceptible, except under strict crop management regimes.

“Eyre Peninsula had the highest level of disease last year, because it was the first region to adopt these varieties. Unless the strict management regimes are followed sylvestris-based varieties planted in other regions in 2004 are likely to be subject to similar levels of disease,” Mr Strong said.

Pacific Seeds co-operated with a GRDC-funded survey late last year which determined the extent of blackleg infestation in sylvestris crops during 2003.

“Our new varieties which have conventional Blackleg resistance, Tornado 555TT and Hyola 61, have proven extremely popular for the 2004 season, and we will be working on both these varieties and our sylvestris resistance varieties in the coming months to ensure we maintain our position as Australia’s leading non-government canola breeder and a major supplier of seeds to the Australian canola industry,” Mr Strong said.