Canaryseed growers should start checking fields for aphids about mid-July, said Scott Hartley, pest management specialist with Saskatchewan Agriculture.
Canaryseed is affected by the dark green bird cherry-oat aphid and the light green English grain aphid, said Hartley.
“Often these aphids are not abundant enough to cause economic losses but, if airflow conditions are favorable for early infestations, significant crop injury can occur,” he said.
Aphids often hide along the small stem inside the canaryseed head. When making counts to determine infestation levels, bend the plant head and inspect it. The bird cherry-oat aphid will also feed on the stems, underside of leaves and in the boot – the area where the flag leaf joins the central stem – before heading.
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Researchers have yet to determine the economic thresholds for aphid infestations in canaryseed in Saskatchewan. Hartley said information from the United States and research into other cereal crops suggests if 50 percent of the tillers have 10 to 20 aphids per stem, chemical treatment might be warranted.
“Canaryseed prices are lower this year so the approximate economic threshold level is 20 aphids per stem. The economic threshold is reduced as the price of canaryseed increases.”
Malathion and dimethoate (Cygon) are registered for control of aphids in canaryseed. Spraying should take place at early heading when aphids are present in sufficient numbers.
Don’t spray after the soft-dough stage of the seed because aphids do little economic damage after that time.
Producers should keep in mind the pre-harvest intervals for these chemicals: seven days for Malathion and 21 days for Cygon.
Hartley said natural biological control exists in the form of beneficial insects such as predatory ladybird beetles and parasitic wasps. He says weather extremes can also reduce aphid numbers.
Further information
More information on control of aphids in canaryseed may be found in the annually updated Saskat-
chewan Agriculture publication Guide to Crop Protection, available at all Sask Ag rural service centres.
Information on aphid control in canaryseed may also be found on the department’s internet site www.agr.gov.sk.ca/saf/crops/crppro98.htm.
