WINNIPEG, Manitoba (Reuters) - A few, rare fields of Canada's canola crop are blooming into the critical flowering stage when yields are made or lost, but widely ranging plant growth makes forecasting the harvest tough this year.
In a normal year, canola flowers for a few weeks in late June and early July. Excessive heat causes its yellow petals to fall off before they can turn into seed pods.
This year, flooding caused staggered planting times across the Prairies and wet, cool conditions have also delayed growth.
"It could be the whole of July (that canola will flower) depending on when they seeded," said Venkata Vakulabharanam, oilseeds specialist for Saskatchewan, the top canola-growing province. "This weekend, we usually see yellow fields, but it's going to be rare this year."
The most flooded areas are southwestern Manitoba and southeastern Saskatchewan, both of which normally grow significant acres of canola. But crops are much healthier this year in northeastern Saskatchewan, a more critical area.
"This is not a normal year and that's why Stats Canada has a difficult time to predict what the numbers are," Vakulabharanam said. "It's really tough."
Statistics Canada will give its first estimates for production on August 24.
Canada is the biggest exporter of canola, also called rapeseed, which is used as a vegetable oil and meal for livestock feed. It is Canada's second-biggest crop after spring wheat.
The weather turned hot across much of the Prairies this week, with the next several days reaching as high as 30 C (86 F) at times.
Canola can survive hot days during flowering if temperatures cool overnight, which seems likely with the ground so wet, said Don Roberts, analyst at Canolainsight.com.
In a normal year, ICE canola futures add a premium if July gets too hot, but futures traders will be hard-pressed to gauge the weather's impact this year during flowering, said Ken Ball, commodity futures and options broker at Union Securities.
"If you get a week of heat, the impact isn't going to be as great (as usual) -- it's going to be impacting a smaller portion of the crop," Ball said.
The result may be that canola futures settle into a cautious, tight range in July, Roberts said.
Moist soils also lessen the risk of excessive heat.
"If it's really hot, I don't think it's going to have that much of an influence as opposed to other years," Roberts said.
Canola faces other threats tied to the Prairies' wet spring. Sclerotinia stem rot disease, which thrives in cool, wet weather, may be "a scourge" because of wet conditions and the presence of it last year, said Murray Hartman, Alberta's oilseed specialist, in an interview posted online by Alberta Canola Producers Commission.
Some crops are also turning yellow as their roots fail to get enough nutrients in waterlogged soil. That can cause loss of yield, but plants may recover as weather improves, said Ingrid Kristjanson, oilseeds agrologist for the Manitoba government.
Past the flowering stage, the next critical event will be the timing of the first major frost. It usually comes in early September, but this year most crops will be too immature to withstand damage at that time.