Summary of Insects on Crops in Manitoba in 2016

A “Summary of Insects on Crops in Manitoba in 2016” is posted on the Manitoba Agriculture insect page at the link http://www.gov.mb.ca/agriculture/crops/insects/pubs/2016-summary.pdf

This report is based partially on observation by myself and my summer assistant. A large part of this information, however, is based on observations and reports from agronomists, farmers, farm production extension specialists, extension coordinators, and others who contributed information over the season. This information was helpful in providing timely updates on where and when insects were of concern throughout the season, and it is a compilation of this data that makes up this summary. Thank you very much to those who contributed information over the growing season.

Note also that the information in the summary is what has been observed personally or reported, and may not be complete in many instances. Although we encourage the reporting of information on insect populations and control to make our weekly updates as complete and useful as possible, some areas of high insect populations and areas where control took place may not have been reported.

I hope this information is useful in your winter planning and preparations for next year

Submitted by: John Gavloski, Entomologist, Manitoba Agriculture

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

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

 

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Will storage of infected grain for over 1 year reduce Fusarium spp. infection and DON levels?

The viability of various Fusarium spp. during storage is dependent on the storage conditions, with temperature playing a key role. Scientific studies have demonstrated that Fusarium infection levels will be reduced when infected grain is stored for at least 6-9 months at a constant temperature of 25 °C and where either relative humidity is >62% or seed moisture content is at least 10-14%. One study demonstrated elimination of Fusarium graminearum when corn seed was stored in sealed containers at 30°C and a seed moisture content of 14%. However, the same is not true for infected grain stored at cooler temperatures (less than 15°C) which are more consistent with the recommendations for grain storage on the Canadian Prairies. At temperatures below 15C the viability of the pathogen (Fusarium spp.) is unchanged, unchanged, especially under drier conditions, making long term storage of infected grain a poor strategy for reducing Fusarium infection levels. Also, if the grain is to be used for seed, prolonged storage of infected grain at higher temperatures and moisture levels may result in reduced vigour and germination rates.

The mycotoxin deoxynivalenol (DON) in Fusarium infected grain is also unaffected by long-term storage, regardless of the temperature. Under safe storage conditions changes in DON levels would be unlikely.

Submitted by

Holly Derksen, Field Crop Pathologist, Manitoba Agriculture

Barbara Ziesman, Provincial Specialist, Plant Disease, Saskatchewan Ministry of Agriculture

Michael Harding, Research Scientist, Plant Pathology, Alberta Agriculture & Forestry

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If my grain has high levels of DON can I still use it for seed?

Deoxynivalenol (DON) is a mycotoxin produced by the fungus that causes fusarium head blight (FHB). The importance of determining DON levels in your harvested grain relates to the use of that product for human/animal consumption. DON is poisonous to humans so it is carefully monitored in grain used for food. Additionally, it is poisonous to livestock and can cause feed refusal and poor weight gain in livestock if present above recommended levels.

The relationships between fusarium-damaged kernels (FDK), seed infection by Fusarium spp., and DON levels are not consistent. Just because FHB was observed in the field and/or FDK were observed in a harvested sample it does not necessarily mean that DON is present. Conversely, the lack of these symptoms does not necessarily mean that DON is not present. The latter situation is often the case in years where conditions are conducive for Fusarium infection after anthesis. These DON levels are not accounted for when grading grain is based solely on the percentage of FDK.

While DON levels may affect the suitability of harvested grain as food or feed, seedling health and seed germination is affected by the extent of infection of seed by hyphae of Fusarium graminearum.  Thus, the level of infection by Fusarium spp., including F. graminearum, is a better measure of whether or not the grain should be used for seed in a subsequent season.

Recommendations:

For purposes of replanting, growers should have seed tested by an accredited lab for germination, vigour, and Fusarium infection levels. Based on this information growers can determine whether or not a grain sample is appropriate for planting (with or without a seed treatment) and whether the seeding rate would need to be adjusted. (See future questions in this series that will address whether or not to plant Fusarium-infected seed.)

For purposes of marketing and livestock feeding, growers should have grain tested for DON levels by an accredited lab. Grain companies and buyers are increasingly requesting information on DON levels as opposed to just FDK.

Submitted by:

Holly Derksen, Field Crop Pathologist, Manitoba Agriculture

Barbara Ziesman, Provincial Specialist, Plant Disease, Saskatchewan Ministry of Agriculture

Michael Harding, Research Scientist, Plant Pathology, Alberta Agriculture & Forestry

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Getting the Facts on Fusarium Head Blight

Fusarium head blight, or FHB, is a major disease that wheat and other cereal producers deal with each year to varying levels. The conditions in 2016 were conducive for infection in both winter and spring wheat as well as other cereal crops (symptoms were observed in both barley and oats). While 2016 was not the worse year on record for FHB in Manitoba (see post on FHB survey results), levels across the prairies were amongst the highest they have been in recent years.

Manitoba Agriculture has partnered with Alberta Agriculture and Forestry and the Saskatchewan Ministry of Agriculture to develop a Q & A series “Getting the Facts on Fusarium Head Blight”. This series will address FHB issues producers faced in the 2016 season as well as issues they are facing regarding infected seed. The answers provided will be a combined effort of the provincial disease specialists with input from researchers at Agriculture and Agri-Food Canada, the University of Saskatchewan, and the University of Manitoba.

If you have a question you would like to see addressed please submit via Crop Chatter or contact your provincial disease specialist.

Submitted by

Holly Derksen, Field Crop Pathologist, Manitoba Agriculture

Barbara Ziesman, Provincial Specialist, Plant Disease, Saskatchewan Ministry of Agriculture

Michael Harding, Research Scientist, Plant Pathology, Alberta Agriculture & Forestry

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2016 Manitoba Fusarium Head Blight Survey

The following are the results of spring and winter wheat fields surveyed for Fusarium head blight (FHB) by Manitoba Agriculture Staff. Fusarium head blight was observed in nearly every field surveyed (97% of winter wheat fields surveyed and 93% of spring wheat fields surveyed). The average FHB index for winter wheat in 2016 was 2.7% which was slightly below the 10-year-average (3.1%). The average FHB index for spring wheat in 2016 was 2.4% which was slightly above the 10-year-average (2.2%).

Winter wheat:

FHB was observed in 30/31 fields surveyed.

Region # Fields Surveyed Average Incidence Average Severity Average FHB Index
Central 13 18% 19% 3.6%
Eastern/Interlake 13 11% 16% 2.6%
Southwest 5 6% 11% 0.6%
MANITOBA 31 13% 16% 2.7%

*No winter wheat fields in the Northwest region were surveyed

Spring wheat:

FHB was observed in 50/54 fields surveyed.

Region # Fields Surveyed Average Incidence Average Severity Average FHB Index
Central 17 29% 12% 3.9%
Eastern/Interlake 17 8% 11% 1.1%
Northwest 10 7% 8% 0.7%
Southwest 10 23% 19% 3.9%
MANITOBA 54 17% 12% 2.4%

 

Submitted by Holly Derksen, Field Crop Pathologist, Manitoba Agriculture

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The Slow Dry Down & Harvest of the 2016 Grain Corn Crop

Modified from a previous Crop Chatter post made November 18, 2014.

November is here and there remains grain corn to be harvested in some parts of Manitoba. In some cases, moisture contents are still higher than wanted or wet field conditions are hampering progress. But with winter approaching, many are opting to harvest under the less than ideal conditions.

What are normal dry down rates in corn? The best dry down rates are in September. Under good weather conditions from the mid to end of September, dry down rates can vary from 0.75 to 1.0% per day (can be greater in some cases when conditions are warm, sunny and dry, or zero on cool, rainy days!). Into early October, dry down ranges from 0.5% to 0.75% per day. In late October, dry down rate will decrease to less than 0.33% per day. And into November, dry down rate will further decrease to 0.15% per day to negligible amounts.

It is important to keep in mind that moisture loss for any particular day may be higher or lower depending on the temperature, relative humidity, sunshine, wind or rain conditions that day.

However, regardless of kernel moisture content in November, if left standing the crop can dry down throughout the winter months to moisture contents below 20%.

Potential Yield Loss.  If the crop remains out longer than anticipated and into the winter months, potential yield loss will depend on many factors, including stalk strength, ear drop, snow cover or wildlife damage. Ear drop will vary by hybrid and environmental conditions as well as the amount of grain on the ear (smaller ears should stay attached better than larger ears).  Stalk strength should also be considered when evaluating harvest timing (and this includes assessments of stalk rots). Compromised stalk strength could lead to increased stalk breakage, resulting in lost yield.

If winter conditions are cool with minimal snowfall, then corn will continue to dry and can be harvested throughout the winter.

If you do find yourself in the position of needing/wanting to overwinter your corn, please touch base with your local MASC agent.

Submitted by:  Pam de Rocquigny, Provincial Cereal Crops Specialist, Manitoba Agriculture

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

 

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Is Manitoba’s Winter Wheat Crop Set Up to Survive Winter?

The most common question I receive over the winter months related to winter wheat production is “How is the cold weather/warm weather/lack of snow impacting my winter wheat?” Unfortunately, there are no easy answers over the winter months as we typically have to wait until spring when winter wheat breaks dormancy and stand establishment is known.

However, there can be a few key factors during fall establishment and weather conditions over the winter months that can provide guidance in terms of assessing weather and its impact to Manitoba’s winter wheat prior to the crop actively resuming growth next spring.

First step: record crop condition prior to winter. The crop stage and health/vigour of the crop as it heads into winter will provide an indication if the crop has a high chance of surviving the winter with minimal winterkill or winter injury. Ideally plants should be at the 3 leaf to 1 tiller stage and have well-developed crown tissue (and of course established into adequate standing stubble to ensure snow catch). And remember, the stage of crop development in the fall influences not only winter survival, but also yield potential, crop competitiveness, maturity and the risk of infection with diseases such as rust and fusarium head blight.

Second step: note the weather after seeding and prior to winter. Cool conditions in the fall where plants grow for 4 to 5 weeks, followed by 4 to 8 weeks (October to November) of growth that allow plant to acclimate and vernalize, is the ideal situation (relates back to an optimum seeding date of the first couple weeks of September). Read more about cold acclimation and vernalization here: http://cropchatter.com/winter-wheat-survival-impacted-by-fall-management-decisions-the-weather/. Another key weather factor is open field conditions with little or no snow cover until freeze-up as this allows soil temperatures to gradually decline to freezing levels.

If your winter wheat crop and the fall weather met the above conditions, your crop is likely well-positioned to survive Manitoba’s winter.

Third step: record any weather stresses over the winter months. In the fall, winter wheat producers can take all the necessary steps to set their crop up to survive winter with minimal winterkill or injury. However, it is often the winter/early spring weather in Manitoba that can impact winter survival.  Producers should take notes of cold snaps (how long they lasted, when did they occur) and the snow cover during those events to gauge potential impact to their winter wheat crop.

Regardless of the amount of cold acclimation, we typically need to receive good snow cover to protect the crop from the sustained cold temperatures normally seen in January and February in Manitoba. The ideal situation would be a minimum of 4 inches of trapped snow cover through December to early March to buffer soil temperature changes and provide protection to the crown tissue.

To assist with recording any soil temperature stresses, there is real-time monitoring of soil temperatures in the four winter wheat fields across Manitoba (see http://cropchatter.com/monitoring-real-time-soil-temperatures-in-manitoba-winter-wheat-fields/). The data will also be made available in the near future to the Winter Cereal Survival Model website at https://www.wheatworkers.ca/wcsm.php which can provide additional information on potential injury due to cold soil temperatures.

Submitted by:  Pam de Rocquigny, Provincial Cereal Crops Specialist, Manitoba Agriculture

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Monitoring Real-Time Soil Temperatures in Manitoba Winter Wheat Fields

Over the past three winters, Manitoba Agriculture through the AgWeather Program has been measuring soil temperatures real-time in winter wheat fields.  The monitoring of soil temperatures can provide an early indication if there is a concern for winter injury or winterkill.  The earlier a problem is identified or suspected, we are able to provide that information to industry so careful assessment of acres occurs in the spring.

There are 4 Manitoba Agriculture AgWeather Program weather stations measuring real time soil temperatures in winter wheat fields.  The sites are at Crystal City, Kleefeld, Oakburn and Virden.  Bookmark the link: ftp://mawpvs.dyndns.org/Tx_DMZ/WWST2016_17.png

In the coming weeks, the data will also be made available to Western Ag for their Winter Cereal Survival Model, available at the following link: http://www.wheatworkers.ca/FowlerSite/winter_cereals/WWModel.php.

I would highly recommend taking the time to read instructions on how to use the site and interpret the results.  Click here for instructions on how to use the model.

Submitted by:  Pam de Rocquigny, Provincial Cereal Crops Specialist, Manitoba Agriculture

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Can Stripe Rust Overwinter in Manitoba?

Short Answer: Yes.

Long Answer: Normally in Manitoba, the majority of our inoculum blows in from the central US states by what is known as the “Puccinia Pathway”. However, according to Dr. Brent McCallum, a Research Scientist with AAFC in Morden, MB, there was evidence of both stripe and leaf rust overwintering on winter wheat in Manitoba a few years ago but at such low levels it wasn’t a concern. Dr. Kelly Turkington, a Research Scientist with AAFC in Lacombe, AB, also indicated overwintering of stripe rust occurred in Alberta and parts of Saskatchewan in 2010/11 where there were measurable losses. In that particular year, there was a breakdown of resistance in the 2010 planted winter wheat crop and that led to higher infections into 2011.

So yes, stripe rust can overwinter. However, the ability of stripe rust to overwinter in Manitoba, or elsewhere, would depend on factors such as the severity of the winter and snowfall amounts.

If stripe rust is seen in the fall, take note of the variety and its resistance rating. Although nothing can be done about variety selection at this point, in the future consider stripe rust resistance when evaluating and selecting winter wheat varieties. Genetics….it’s a fast and easy way to protect your crop from disease pressure!

If winter weather conditions allow for overwintering of stripe rust, it could provide a local source of inoculum early in the spring – as early as the crop starts actively growing. A cool, wet spring could also favor spread and infection of stripe rust, not only to winter wheat but to other crops such as spring wheat.

If you do see stripe rust this fall in your winter wheat crop, mark those fields as ones to watch as soon as the crop breaks dormancy next spring. If stripe rust does overwinter, a fungicide application may be necessary.

Should a fall fungicide application be considered?

There has been some recent research conducted looking at the yield response and economics of a fall fungicide application in winter wheat. From 2011 to 2013, researchers from AAFC conducted a study across Western Canada looking at a variety of management factors, including one looking at a fall fungicide application. Results were recently reported in Top Crop Manager at http://www.topcropmanager.com/business-management/improving-winter-wheat-19554. The following statements are from the article.

In regards to the fall fungicide treatment, “the study showed some benefit from the fall foliar fungicide treatment, however the increase was small and resulted in decreased net returns,” says Turkington (who was involved with the study). “In areas with confirmed stripe rust in the fall, the yields gains were a bit better. However the cost of application is prohibitive at this point compared to no application. ”

More research is currently underway by Turkington and Dr. Randy Kutcher (University of Saskatchewan) looking at a fall fungicide application, a spring fungicide application at flag leaf emergence, and a dual application (one in the fall and one in the spring).  “The preliminary results after the first two years aren’t showing much of a benefit from the fall foliar fungicide application, similar to our recent study,” Turkington says. “Some of the results suggest a dual fall and spring application does not provide any additional benefit over a spring application in Western Canada.”

So for this fall, don’t pull out the sprayer if you see stripe rust in your winter wheat.  But, be ready to scout in the spring! And look for more updates to current winter wheat research underway across Western Canada.

Submitted by: Pam de Rocquigny, Provincial Cereal Crops Specialist and Holly Derksen, Field Crops Pathologist, Manitoba Agriculture; with assistance from Dr. Brent McCallum, AAFC Morden and Dr. Kelly Turkington, AAFC Lacombe.

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

 

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Testing Weeds for Herbicide-Resistance

Do you have weeds that survived this year’s herbicide application(s)? Since there are many factors that can contribute to weed escapes, consider:

  • The distribution of escaped weeds. Herbicide-resistant weeds tend to occur in patches as opposed to geometric patterns (e.g. spray miss) or throughout the field (e.g. tolerant weeds).
  • Possibility of reduced herbicide efficacy. 2016 was a challenging year for weed management due to untimely and excessive rainfall. In many cases, weeds escaped because of herbicide application timing with respect to weed growth stage, limited herbicide choices because of crop growth stage (when producers finally could get on their fields) and product rainfastness.
  • Weed species. Annual weed species, like wild oat, green foxtail, cleavers, kochia, hemp-nettle, smartweeds, ragweeds and wild mustard, may be more likely to develop resistance compared with other weed species. Because the development of herbicide-resistance is based on chance, resistant weed patches are typically a single species, as opposed to non-resistant weed escapes, which may affect multiple weed species.

Suspect weed escapes can be confirmed as resistant or susceptible by herbicide-resistance testing. For most weeds, dry, mature seed is required for the analysis.  Although more is better, many labs require at least 100 g of small weed seeds (e.g. cleavers) and 200-250 g of large weed seeds (e.g. wild oat).  Weed seed samples should be submitted by December 31st, 2016 to either:

For suspected glyphosate-resistant kochia, a genetic-based tissue test is also available from the Pest Surveillance Initiative: http://www.mbpestlab.ca/field-testing/. In this case, about 5 to 10 g of green plant tissue (e.g. leaves and stems from plant tips) is needed for the analysis. Samples should be placed on ice and shipped immediately after collection. The advantage of the genetic test (vs. seed analysis) for kochia is the ability to determine resistance in-season.

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Submitted by: Jeanette Gaultier, Provincial Weed Specialist, Manitoba Agriculture

For more information on resistant weeds and weed management, visit the Manitoba Agriculture website: http://www.gov.mb.ca/agriculture/crops/weeds/

 

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