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Manitoba Agriculture, Food and Rural Initiatives

Manitoba Insect and Disease Update

May 17, 2010                   

Compiled by: John Gavloski, Entomologist, Manitoba Agriculture, Food and Rural Initiatives
                    Phone: (204) 745-5668; Fax: (204) 745-5690, and
                    Vikram Bisht, Plant Pathologist, Manitoba Agriculture, Food and Rural Initiatives
                    Phone: (204) 745-0260; Fax: (204) 745-5690

To report observations on insects or plant pathogens that may be of interest or importance to farmers and agronomists in Manitoba, please send messages to the above contact address.

To be placed on an E-mail list so you will be notified immediately when new Manitoba Insect and Disease Updates are posted, please contact John Gavloski at the address or numbers listed above.


• Wheat streak mosaic has been confirmed on wheat from a few fields in Central and Southwest Manitoba.
• Diamondback moth have been found in some traps.
• Flea beetle feeding can be seen on volunteer canola.

Recent Insect and Plant Pathogen Activity

Flea beetles: Flea beetle feeding is common on volunteer canola across Manitoba. This feeding is expected this time of year, particularly on hot and calm days. Canola that has been seeded without a seed treatment containing an insecticide, and canola seeded in April should be monitored for the amount of flea beetle feeding that is occurring.

Wheat Streak Mosaic: Volunteer winter wheat from 3 fields has tested positive for wheat streak mosaic virus. The fields where it has been found so far are south of Brandon, near Somerset, and near Boissevain. Wheat curl mites, which vector the virus, were also observed using a microscopic.

Volunteer winter wheat must be completely dried/ killed before spring wheat can be planted safely. Otherwise the risk of infective mites spreading into the spring crop is very high. Seven to 10 days of no grassy crops or grassy weeds is recommended to prevent live grassy plants “bridging” the mites to the next crop.

Tan Spot: Volunteer spring wheat plants from last year’s wheat crop were found to have tan spots in one field in the Carman area. High moisture provided good conditions for the pathogen to infect the young seedlings. An effective control of infective volunteers would prevent inoculum getting into the regular spring crop.


Surveys and Forecasts

Diamondback moth: Adult diamondback moths have already been found in pheromone-baited traps in several areas of Manitoba. Trap counts so far include; 18 from a trap near Emerson, 5 near Altona, 5 near Carman, 2 near Hamiota, and 1 near Teulon. This does indicate an early arrival of the moths. Conditions have been good over the past several days for survival and egg-laying, and with favorable weather in the forecast diamondback moth could get off to an early start. Traps for diamondback moth are placed in fields (even if not yet seeded) in early May to monitor when diamondback moths begin to arrive in Manitoba.

Data for the diamondback moth monitoring program is updated at the beginning of every week on the MAFRI website at:


New Resources

Addendum to Guide to Field Crop Protection 2010. The addendum for the Guide to Field Crop Protection 2010, in addition to the guide, is now posted online at:

Integrated Pest Management of Sunflower Insect Pests in the Northern Great Plains. A guide to “Integrated Pest Management of Sunflower Insect Pests in the Northern Great Plains” is now available either as hardcopy or online at: