Field Scouting Necessary

REGINA - May 10/04 - SNS -- Much of the pulse planting seed in use this year is disease free, but growers still need to scout fields for early signs of disease outbreaks so they can work early on controlling their spread, warns Saskatchewan Agriculture.

Based on disease surveys conducted in the field last year, as well as on reports from commercial seed-testing labs, the incidence of all crop disease was low during the 2003 growing season in Saskatchewan. This will result in less disease risk in 2004.

"But this situation could change if we get more rain. It's still important that farmers scout their fields at the appropriate time," says Penny Pearse, plant disease specialist with Saskatchewan Agriculture, Food and Rural Revitalization.

Last year's hot dry weather during July and August is responsible for diseases that, in some cases, hit the lowest levels in six years, says Pearse. It's no surprise that seed-borne diseases are not an issue for 2004: there were few reports of in-field disease issues in 2003 - even in chickpea, says Pearse.

More specifically, the results of the Fusarium Head Blight (FHB) Survey show the lowest prevalence (percentage of fields infected) and severity (percentage of kernels infected) since the survey began in 1998. The severity values of FHB on wheat, for example, were trace for all soil zones. Fusarium graminearum, the Fusarium species that is most dangerous because of its production of mycotoxins, was isolated at low levels from only three wheat fields, and these were in areas where this species is considered established: south-east Saskatchewan and irrigated regions.

The incidence and severity of FHB in barley in 2003 was the lowest reported since the survey began in 1999, again because of the hot dry weather.

Low levels of pulse crop diseases were also reported from the province's seed-testing labs. Infections of lentil, pea and chickpea by ascochyta fungi were at the lowest values recorded for the past five years. In fact, the majority of seed samples were free from ascochyta infection in 2003. The majority of seed samples tested were free from botrytis infection as well. As in previous years, very few pulse samples were infected with sclerotinia, and very few lentil samples with anthracnose. The only significant pulse disease in the fields in 2003 was powdery mildew of field pea.

Samples received by the province's seed-testing labs also indicate good-to-excellent germination rates. They are substantially higher than last year, in fact. "Germination and disease often go hand-in-hand: high disease levels and low germination; or, as is the situation this year, low disease levels and high germination," Pearse explains.

The dry conditions of 2003 did not amortization sclerotinia infection on canola. The mean incidence was 0.4 per cent for the province. In fact, no significant yield loss has occurred as a result of this disease in recent years. Blackleg on canola was similar to previous years, with a mean incidence of 3.4 per cent for the province. Pearse says blackleg is one disease that is not deterred by dry weather.