Manitoba farmers harvested a generally average sunflower crop in 2008, despite ongoing disease and insect problems.
Producers reaped an average 1,480 pounds per acre of confectionery and oil-type sunflowers from 182,000 planted acres, according to provincial crop insurance figures.
That compared favourably with the long-term four-year average yield of 1,460 pounds per acre from an average of 184,000 acres.
But cool, wet weather during the growing season kept 2008 sunflower yields below those for 2007 (1,550 lb./ac. from 176,000 acres) and 2006 (1,910 lb./ac. from 192,000 acres), producers heard here at last week’s St. Jean Farm Days.
Long-term average yields in Manitoba are also skewed by a poor crop in 2005, when yields averaged only 900 lb./ac.
Recurring pest problems were again common in Manitoba sunflower fields this past year, Anastasia Kubinec, a provincial oilseed specialist, told producers.
Surveys detected sunflower rust in 74 per cent of fields between July and September. By late September, 100 per cent of surveyed fields showed signs of the disease.
This was the first time since 2003 that sunflower rust was very visible in Manitoba, Kubinec said. A previous outbreak occurred in 1999. No fungicides are currently registered in the province for sunflower rust control.
Sclerotinia is a disease seen almost every year in sunflowers and 2008 was no exception. Its forms are basal wilt, caused by sclerotia from a previous crop, and mid-stalk and head rot resulting from spores which arrive on the wind.
Insects observed in 2008 included the sunflower bud moth (prevalent throughout the province), the banded sunflower moth in the central region and the lygus bug in the eastern and central regions. The red sunflower seed weevil was also detected, but at very low levels.
A 2008 National Sunflower Association of Canada survey found 72 per cent of inspected fields had damage from the
bud moth. Of those, an average 28 per cent had “holes” in the heads of plants. Damage was highest in areas east of Carman.
Insect sightings were high for both bud moths and lygus bugs, and medium to high for the banded moth.
Chemical controls for diseases and insects in sunflowers are limited. For weed control in sunflowers, only eight herbicides are listed in the provincial Agriculture Department’s Guide to Crop Protection. Clearfield-tolerant sunflowers are grown in Manitoba.
Kubinec said NSAC is working to get a minor use label for Headline, a fungicide to control sunflower rust.
In the meant ime, she advised growers to watch their crops rotations and use clear fields with no history of sclerotinia or other disease infection.