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Manitoba Insect & Disease Update – Issue 10: July 20, 2016

The Manitoba Insect and Disease Update is now posted at: http://www.gov.mb.ca/agriculture/crops/seasonal-reports/insect-report-archive/insect-report-2016-07-20.html

Some highlights from the update:

Insects:

  • Pea aphid levels are still a concern in some pea fields, although many fields will be getting to the stage where management would no longer be economical.
  • Aphid levels have dropped in many cereal fields where previously levels had been increasing. High levels of natural enemies have been noted in some of these fields, and some intense rains may have also contributed.
  • In some areas of Central and Southwest Manitoba, greater than 90% of the wheat midge are expected to have emerged. In many areas of Manitoba about 50 to 90% of wheat midge are expected to have emerged. A reminder that wheat that has already produced anthers is no longer susceptible to feeding by wheat midge. Even if adults are still active in these more advanced fields, the larvae will not feed on the grain.
  • Egg masses of European corn corer are starting to be noted in some fields of corn. So far there are no reports of high levels, but now is the time to be checking fields for the egg masses.
european-corn-borer-egg-masses

Figure 1. Egg masses of European corn borer.

Plant Pathogens:

  • Some infections of blackleg in canola and fusarium head blight in cereals have been reported.
  • A few cases of loose smut in barley were also reported.
  • Two positive identifications of Goss’s Wilt in corn were made. The positive identifications were made based on immunostrips and/or polymerase chain reaction (PCR) assays.

Submitted by: John Gavloski, Entomologist & Pratisara Bajracharya, Field Crop Pathologist, Manitoba Agriculture

Manitoba Agriculture website: www.manitoba.ca/agriculture
Manitoba Agriculture on Twitter: @MBGovAg
Manitoba Agriculture on YouTube: www.youtube.com/ManitobaAgriculture

 

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Manitoba Insect & Disease Update – Issue 7: June 29, 2016

The Manitoba Insect and Disease Update is now posted at: http://www.gov.mb.ca/agriculture/crops/seasonal-reports/insect-report-archive/insect-report-2016-06-29.html

Some highlights from the update:

Insects:

  • Alfalfa weevil is still at high levels in some alfalfa fields. Some alfalfa hay fields are being cut early as a result.
  • Pea aphid levels are near or above economic threshold in some pea fields, although levels are sporadic as other fields have quite low levels.
  • A map is provided that shows the percent of wheat midge that are expected to have emerged, based on models using degree days to calculate percent emergence. We are generally above average for degree day accumulation in Manitoba, and it is likely that wheat midge emergence has started in Manitoba, although in many areas it may only be about 10% of the wheat midge that have emerged (light yellow on the map). Some areas of Central and Southwest Manitoba may have closer to 50% emergence (darker yellow on the map).

Plant Pathogens:

  • Brown spot and root rots were found in some soybean fields.
  • Scouting should be continued for rust diseases in cereal crops.
  • A few cases of bacterial blight in cereal crops have been reported.
  • A few cases of downy mildew in sunflowers have been reported.

Submitted by: John Gavloski, Entomologist & Pratisara Bajracharya, Field Crop Pathologist, Manitoba Agriculture

Manitoba Agriculture website: www.manitoba.ca/agriculture
Manitoba Agriculture on Twitter: @MBGovAg
Manitoba Agriculture on YouTube: www.youtube.com/ManitobaAgriculture

 

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Manitoba Insect & Disease Update – July 28 to August 1, 2014

A Manitoba Insect and Disease Update for the week of July 28-August 1, 2014 has been posted at: http://www.gov.mb.ca/agriculture/crops/seasonal-reports/insect-report-archive/insect-update-2014-08-01.html

Highlights include:

Pathology:

  • Fusarium head blight risk for wheat is moderate to low in different areas of Manitoba. Most of the wheat crops have finished flowering and thus at low risk. By end of the month, Fusarium head blight risk maps may not be needed.
Entomology:
  • Grasshoppers continue to be a concern in some fields.
  • Canola growers should be checking canola for Lygus bugs. Lygus can potentially be of concern when they feed on the pods of canola if levels are high, although feeding to flowering crops is not likely to be economical as canola has a very good ability to compensate for damage to flowers, especially when soil moisture is good. So far Lygus levels appear to be below economic levels in canola, with a few exceptions in the Eastern part of Manitoba.

Note: For those monitoring traps for bertha armyworm, the traps can be removed after you do your counts this week. We have enough weeks of data to know what the regional risks are. Overall trap counts in Manitoba were quite low this year. A map of the cumulative counts, as of July 28th, is posted in the update, and risk maps are also posted at the following MAFRD website (the July 28th map will be posted tomorrow): http://www.gov.mb.ca/agriculture/crops/insects/bertha-armyworm-forecast.html

Submitted by: John Gavloski, Entomologist & Vikram Bisht, Pathologist, MAFRD

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Manitoba Insect & Disease Update – Week of July 21st to 25th

A Manitoba Insect and Disease Update for the week of July 21-25, 2014 has been posted at: http://www.gov.mb.ca/agriculture/crops/seasonal-reports/insect-report-archive/insect-update-2014-07-25.html

Highlights include:

Pathology:
  • Goss’s wilt and leaf blight disease are showing up in corn.

Corn leaf with well developed leaf blight of Goss’s Wilt disease. Photo: Vikram Bisht, MAFRD

  • Ergot disease infection is now showing up in fall rye and grasses.
  • Blackleg infection on lower stems/roots on canola is showing up.
  • Downy mildew on sunflowers is reported.
Entomology:
  • Grasshoppers are starting to mature to the adult stage. How much they move into crops from surrounding vegetation may partially depend on how lush the roadside vegetation remains relative to the crop.
  • Still no soybean aphids found in Manitoba in 2014.

Submitted by: John Gavloski, Entomologist & Vikram Bisht, Pathologist, MAFRD

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Manitoba Insect & Disease Update – Week of July 14th to 18th

A Manitoba Insect and Disease Update for the week of July 14-18, 2014 has been posted at: http://www.gov.mb.ca/agriculture/crops/seasonal-reports/insect-report-archive/insect-update-2014-07-16.html

Highlights include:

  • Flowering canola crop needs to be protected against white mold since there have been many rain events lately.
  • Phytophthora root rot of soybean has started showing up, especially in flooded fields.
  • Early lesions of sunflower rust have been found in a 2nd location.
  • Alfalfa weevil levels were quite noticeable in some alfalfa fields, but they are now starting to pupate, so levels are declining.

Submitted by: John Gavloski, Entomologist & Vikram Bisht, Pathologist, MAFRD

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Manitoba Insect & Disease Update – Week of June 30 to July 4

A Manitoba Insect and Disease Update for the week of June 30 to July 4, 2014 has been posted at: http://www.gov.mb.ca/agriculture/crops/seasonal-reports/insect-report-archive/2014-07-02-insect-update.html

  • Information is provided on the potential effects of flooded fields on grasshoppers and wireworms.
  • Brown spot and bacterial leaf blight have been occurring in some soybean fields; risk of Fusarium head blight in cereals is high to extremely high.
2014-07-03-brownspotdisease

Brown spot disease on lower leaves of canopy. Photo courtesy: Vikram Bisht, MAFRD

  • Forecasts for emergence of wheat midge and a key parasitoid of wheat midge are provided.

Submitted by: John Gavloski, Entomologist & Vikram Bisht, Pathologist, MAFRD

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