Manitoba Insect & Disease Update – Issue 6: June 22, 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-2016-06-22.html

Some highlights from the update:

Insects:

  • Cutworm and flea beetle levels and damage continues to decline.
  • Alfalfa weevil is being noted at high levels in some alfalfa fields
  • Barley thrips are quite noticeable in some barley fields in Eastern Manitoba.
  • Low levels of English gain aphid and oat-birdcherry aphid are being found in some cereal fields.
  • Pea aphid is showing up in some pea crops.

Plant Pathogens:

  • Cereal rust diseases continue to develop and spread.
  • Bacterial blight symptoms in winter wheat and oats were also reported.
  • Root rot pathogens continue to cause problems in soybean fields.

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 5: June 15, 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-2016-06-15.html

SUMMARY:
Insects: Cutworms continue to be an issue in some areas. Flea beetle feeding continues, although foliar use of insecticides for flea beetle management has not been widespread. In many fields plants are now getting to stages more tolerant to feeding by flea beetles. Alfalfa weevil is being noted at high levels in some alfalfa fields.

Plant Pathogens: Rust diseases in cereal crops and sunflower have been observed in Manitoba. Root rots in soybeans have also been reported from various locations in Manitoba. Scouting and monitoring progression of disease symptoms in the field will help in making fungicide application decisions.

Several samples of soybeans showing root rot symptoms have been submitted to Manitoba Agriculture’s Crop Diagnostic lab. Root rot is soybeans are caused by pathogens like Fusarium spp, Phytophthora sojae, Rhizoctonia spp and Pythium spp

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 4: June 8, 2016

The Manitoba Insect and Disease Update for this week is now posted at: http://www.gov.mb.ca/agriculture/crops/seasonal-reports/insect-report-archive/insect-report-2016-06-08.html

Summary
Insects: Cutworms are getting larger and have been an issue in some fields. The highest level of damage appears to be in the Northwest, where there has been some reseeding because of cutworm feeding. Flea beetle feeding continues, although foliar use of insecticides for flea beetle management has not been widespread. In many fields plants are now getting to stages more tolerant to feeding by flea beetles.

Plant Pathogens: Stripe rust has been detected in Manitoba. Scout for stripe rust and report any detection. Stripe rust incidences will need to be closely monitored.

Stripe Rust in Winter Wheat Near Gladstone, MB (June 8, 2016)_A.Knaggs

Stripe Rust in Winter Wheat Near Gladstone, MB (June 8, 2016). Photo by A. Knaggs.

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 204.745.5668.

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

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Manitoba Insect & Disease Update – Issue 3: June 1, 2016

The Manitoba Insect and Disease Update for June 1, 2016 is now posted at: http://www.gov.mb.ca/agriculture/crops/seasonal-reports/insect-report-archive/insect-report-2016-06-01.html

SUMMARY

Insects: Cutworms and flea beetles on canola continue to be the insects of greatest concern. The cool, damp weather from the last few days would have slowed cutworm feeding, and the soil moisture, where not excessive, may help the plants compensate for feeding. Cutworm levels are quite variable, hard to find in some fields, more noticeable in others. So scout for potential cutworm feeding on emerging plants and dig for the larvae if you find an area that is showing signs of cutworm feeding. Precautionary insecticide applications, if cutworm levels are not economical, is not encouraged because of the potential damage to beneficial invertebrates.

Plant Pathogens: Rain has not only provided enough moisture for crops, but also for pathogens causing various crop diseases. Look for early signs and symptoms of diseases in crops. Scout! Scout! Scout!

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

Visit the Insect Pages of our Manitoba Agriculture website at http://www.gov.mb.ca/agriculture/crops/insects/index.html
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Manitoba Insect & Disease Update – Issue 2: May 25, 2016

The Manitoba Insect and Disease Update for this week is now posted at: http://www.gov.mb.ca/agriculture/crops/seasonal-reports/insect-report-archive/insect-report-2016-05-25.html

SUMMARY

Insects: Cutworms and flea beetles on canola are the insects of greatest concern currently. Seed treatments should still be effective against flea beetles in most canola fields, although scouting for feeding damage is encouraged, especially in the earlier seeded fields where seed treatments may soon start losing effectiveness. Cutworm levels are quite variable, hard to find in some fields, more noticeable in others. So scout for potential cutworm feeding on emerging plants and dig for the larvae if you find an area that is showing signs of cutworm feeding.

Plant Pathogens: Scouting for stripe rust in wheat and seedling diseases in emerging crops will be important.

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

Visit the Insect Pages of our Manitoba Agriculture website at http://www.gov.mb.ca/agriculture/crops/insects/index.html

 

 

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Manitoba Insect & Disease Update – Week of June 23 to 27

A Manitoba Insect and Disease Update for the week of June 23-27, 2014 has been posted at: http://www.gov.mb.ca/agriculture/crops/seasonal-reports/insect-report-archive/2014-06-24-insect-update.html

A few quick highlights from the update:

  • Fusarium head blight risk is currently high for winter wheat close to or already heading.
  • Rhizoctonia root rot is also being seen in some soybean fields.
rhizoc-root-rot-soy

Rhizoctonia root rot with reddish-brown discoloration. Photo courtesy: Vikram Bisht, MAFRD

  • Cutworms remain a concern in some areas, although levels of larvae should start to decline as they pupate.

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

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Manitoba Insect & Disease Update – Week of June 16th

A Manitoba Insect and Disease Update for the week of June 16-20, 2014 has been posted at: http://www.gov.mb.ca/agriculture/crops/seasonal-reports/insect-report-archive/2014-06-17-insect-update.html

Highlights include:

  • Cutworms continue to be an issue in some areas.
  • Flea beetle populations remain a concern in some areas, although the cool weather and advance of many canola fields to stages more tolerant to feeding has resulted in decreased damage.
  • Grasshoppers are emerging, but generally still in the first and second instar stages.
G

Juvenile grasshopper (left) and non-economical species of leafhopper (right) (MAFRD)

  • Alfalfa weevil larvae are starting to be noticed in some alfalfa fields.
  • Brown spot (Septoria) and bacterial leaf blight have been observed in soybeans.
S

Early stage of bacterial blight spots and brown spot disease on unifoliate leaves of soybean (MAFRD)

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

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Manitoba Insect & Disease Update – Week of June 9 to 13th

A Manitoba Insect and Disease Update for the week of June 9-13, 2014 has been posted at: http://www.gov.mb.ca/agriculture/crops/seasonal-reports/insect-report-archive/2014-06-10-insect-report.html

HIGHLIGHTS INCLUDE:

Current Insect Scouting Priorities

  • Flea beetles: Foliar spraying, in addition to the seed treatments, is occurring in many areas.
  • Cutworm: Dingy and redbacked cutworms seem to be our dominant species.  How long will they feed? Will crops compensate for some cutworm feeding?
D

Dingy Cutworm

  • Check field edges to assess levels of emerging grasshoppers.

Insect Monitoring Update

Diamondback Moth: It is likely that we had a moderate population of diamondback moth blow into some areas of Manitoba.  Weekly maps for the monitoring program for diamondback moth can be found at: http://www.gov.mb.ca/agriculture/crops/insects/diamondback-moth-monitoring.html

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

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Manitoba Insect & Disease Update – Week of June 2 to 6, 2014

A Manitoba Insect and Disease Update for the week of June 2-6, 2014 has been posted at: http://www.gov.mb.ca/agriculture/crops/seasonal-reports/insect-report-archive/2014-06-03-insect-update.html

Highlights Include:

  • When does the canola become more resistant to flea beetles?
  • Estimating % defoliation. Estimating % defoliation can be tricky, as our eyes are drawn to the damage and it is easy to overestimate  how much feeding has occurred. Having a photo key as a guide can be useful for learning to assess defoliation levels.
  • Cutworm Feeding.  High levels of feeding by cutworms has been noted in sunflowers in the Carman and Sanford areas, and in corn in the Starbuck area.
  • Insecticide application tips for cutworms.
  • Insect Monitoring Programs: 
    • Diamondback moth: Diamondback moth counts have increased in some locations in eastern Manitoba and the Swan River Valley.
    • Bertha armyworm: The map provided in the report indicates at what stage the pupae of the bertha armyworm are in their development. Currently, some may have accumulated enough heat to be about 60-75% through their pupal development.

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

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Four Early-Season Insects to Look For

Cutworms

  • There are different species, which will affect crops differently and may be present at different times.
  • Dingy cutworm overwinter as partially grown larvae, so will be ready to feed as the crop emerges. They will feed on emerged plant tissue, but don’t do a lot of clipping of stems.
  • Redbacked cutworms overwinter as eggs, so may not be noticed until later in May or June, when larger larvae are feeding on plants. They potentially will clip stems.
  • Cutworms can be patchy in a field. Areas of the field that had later flowering crop or weed patches last year may have higher levels of cutworms.
  • Cutworms are nocturnal, feeding during the night, then burrowing into the soil during the day. They will burrow deeper if the soil is dry.
  • If insecticides are needed to control cutworms, they should be applied as late in the day as practical, and may only be needed on patches, depending on how the population is distributed in the field.
  • More information on cutworms can be found at : http://www.gov.mb.ca/agriculture/crops/insects/cutworms-field-crops.html

Flea beetles in canola

  • The 2 main species of flea beetles in canola in Manitoba are the striped and crucifer flea beetles.
  • These are potentially a concern from the time canola emerges until about the 3 to 4 leaf stage in canola.
  • Seed treatments will provide early season control. None of the seed treatments currently registered work as well under cool, wet conditions as they do in warmer, drier conditions.
  • Insecticide effectiveness can vary with the species of flea beetle. Neonicotinoid-based seed treatments (Helix, Prosper) work well against crucifer flea beetle, but control will be less on striped flea beetle. This is not a developed insecticide resistance, just natural variation in effectiveness between species.

Wireworms

  • Are larvae of click beetles. Will have 3 small pair of legs at the front the body, but don’t have the fleshy prolegs at the back like cutworms.
  • Feeding is all underground.
  • Foliar insecticides will not be effective.
  • Seed treatments can stop wireworms from damaging young crops, however current seed treatments result in little mortality of the wireworms.
  • Are hard to monitor; bait balls can be used, but growing vegetation and other sources of CO2 near a bait ball will compete for wireworms and reduce effectiveness.
  • Practices that result in quick germination and early growth can help minimize damage form, wireworms.
  • More information on wireworms, as well as some insects that could be confused with wireworms, can be found at: http://www.gov.mb.ca/agriculture/crops/insects/wireworms.html

Grasshoppers

  • It will probably be early-June before we see much hatch of our potential pest species of grasshoppers this year.
  • Any larger grasshoppers seen in May will not be pest species.
  • Heavy rains and standing water will not kill grasshopper eggs. Newly hatched grasshoppers, however, are quite susceptible do being killed because of heavy rains. So heavy rains in April or May will likely do little to our pest species of grasshoppers. Heavy rains in June could potentially reduce populations significantly.
  • Areas that had lush green vegetation late last year, such as along field edges, are more likely to have higher concentrations of grasshopper eggs, and early-season grasshopper levels will be heaviest in these areas. These areas should be monitored in June.
  • If grasshopper control is needed:
    1. Control of young grasshoppers is more effective than controlling adults
    2. Control may only be needed along field edges or areas where they are concentrated early.
    3. Bran baits (with an attractant that lures the grasshopper to the bait) as well as foliar sprays are available.

Submitted by:  John Gavloski, MAFRD Extension Entomologist

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