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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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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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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Are Herbicides Still Effective After a Fall Frost?

Fall is a great time to control perennials such as Canada thistle, perennial sow thistle and dandelion. As temperatures cool, nutrients move from the leaves down into the roots and if a herbicide can be taken up and translocated with those nutrients, it can equal better control. Glyphosate and/or the group 4s are examples of herbicides that provide effective fall control of perennials.

A frost event though, can kill some weeds or can damage leaf tissue which will reduce herbicide uptake and reduce the level of weed control. Within the next few days after the frost, you need to assess the target weeds in the areas that you want to obtain control – are the weeds still growing?  How much leaf tissue has been damaged?

Light frost: A light frost (0 to -3°C) can actually improve weed control by increasing herbicide translocation to the root.  However, duration of the frost also plays a role.  Check your weeds for frost damage if you plan on a herbicide application after a light frost.  Herbicides can only be taken up and translocated by weeds that are healthy and actively growing.

If you do spray – spray in the afternoon when temperatures are warm and sunny, as this will help with herbicide uptake.   You’re looking for daytime temperatures of ~8 to 10°C for at least 2 hours. Use rates appropriate to the stage and time of year – fall applications of glyphosate are recommended at a higher rate than when controlling weeds pre-harvest.

Hard frost: Depending on the damage, a hard frost (≤ -5°C) can put an end to (effective) post-harvest weed control. However, if the plant leaves are still shiny green with minimal leaf tissue damage (i.e. not blackened/brown or brittle) or if less than 40% of the plant has more serious leaf tissue damage (i.e. blackened/brown or brittle) there may still be a window to make a herbicide application. Wait at least 48 hours before assessing frost damage after a hard frost.

If you do spray – read the ‘If you spray’ paragraph above, it still applies.  You need those daytime temperatures to hit ~8 to 10°C for at least 2 hours. In addition, consider your coverage – higher water volumes may improve uptake in more heavily damaged weeds.

One last thing – look at the forecast for the next week following the application.  If daytime temperatures are below 8°C and/or if night-time temperatures are forecasted to continually be below freezing, it may be too late to make the application to get the economic control you are looking for.

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

Visit Manitoba Agriculture Crops webpage for more current topics: www.gov.mb.ca/agriculture/crops/seasonal-reports/current-crop-topics.html#agronomy; or the Manitoba Agriculture Weeds webpage for more information on fall control of dandelion and quackgrass: www.gov.mb.ca/agriculture/crops/weeds/.

 

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ANNUAL OR WINTER ANNUAL?

Fall is the most effective time to manage certain weed species. The recommendations seem clear-cut:  winter annuals = fall herbicide application/tillage; annuals = no fall management.  But figuring out the life cycle of the weeds in your field this fall is the catch……

Bromes, cleavers, chickweed, night-flowering catchfly, narrow-leaved hawk’s-beard, shepherd’s-purse and stinkweed are all facultative winter annuals, meaning that they can germinate in either the fall or the spring depending on environmental conditions.  These weeds are often best managed in the fall, if populations warrant it.  In general, waiting until about this time of year maximizes fall-germinating flushes of winter annuals.  If using a herbicide, consider weed stage and the weather forecast, prior to application.

The problem is, given the right conditions – like the long falls and mild winters we’ve had the last few years –several of our annual weed species can also successfully overwinter:

Biennial wormwood – Despite its name, biennial wormwood behaves like an annual in agricultural fields.  When scouting, estimate the average growth stage of biennial wormwood populations in a field.  If the majority of the plants have already set seed, a fall herbicide application won’t help.  An application may be worthwhile only if there is a large flush of biennial wormwood that haven’t set seed and are less than ~3 inches tall.  Herbicide tank-mixes containing glyphosate + group 4 are more effective than glyphosate + group 2 on this weed.

Round-leaved mallow (RLM) – This annual weed can act as either a winter annual or a short-lived perennial, although it is more sensitive to freezing than our common winter annuals.  Mild winters in 2015 & 2016 provided the right conditions for RLM to overwinter, allowing it to become (even more) problematic in certain fields over the last few growing seasons.  Long range forecasters are predicting a harsh winter across the prairies this year, which should control RLM.  However, if you have little faith in forecasts and decide to apply a herbicide, glyphosate mixed with either Distinct or DyVel DSp has activity on this weed.

IMG_20150915_081215

Round-leaved mallow post-harvest


Stork’s bill –
Like biennial wormwood, stork’s bill tends to be predominantly an annual in Manitoba.  If this is a problem weed for you, scout affected fields to determine average weed stage.  Again, if most of your stork’s bill has set seed you’re better off working on a plan for next year.  Stork’s bill, especially larger plants, is relatively tolerant of many herbicides.  If you decide to apply a herbicide because of stork’s bill this fall, glyphosate + group 2 or glyphosate + group 2 + group 4 on weeds up to the 4 to 6 leaf stage is probably your best bet.

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

Information on more weeds and their life cycles is available at: www.gov.mb.ca/agriculture/crops/weeds/
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Winter Wheat Survival – Impacted by Fall Management Decisions & the Weather!

For winter wheat, survival through our cold Manitoba winters is directly influenced by fall management decisions, including variety selection, seeding date and depth, adequate plant stands, fertility and stubble height/density. Optimal winter survival can also be influenced by fall weather conditions and snow cover.

What is the ideal situation heading into the winter?

  • Plant stage would be at the 3 to 4 leaf with 1 to 2 tillers, and well developed crown tissue.
  • Cool conditions in the fall, where plants would grow for 4-5 weeks, followed by 4-8 weeks (October to November) of growth that allowed plant to acclimate (harden off) and vernalize (giving the plant the signal to flower next spring).
  • 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.

What is cold acclimation and vernalization? 

Cold Acclimation. The ability of the winter wheat plant to survive the winter often depends on its ability to withstand low temperatures.  Under normal field conditions, eight to twelve weeks of growth is usually required for the full development of winter hardiness.  The first four to five weeks is a period of active growth that takes place when average daily soil temperatures at a depth of two inches (5 cm) are above 9°C. Both the cold acclimation process and winter survival require energy and this period of warm temperature allows for the establishment of healthy vigorous plants. Plants with well developed crowns before freeze-up are most desirable.  However, plants that enter the winter with two to three leaves are usually not seriously disadvantaged.

Cold acclimation of winter wheat plants begins once fall temperatures drop below 9°C.   In the field, four to eight weeks at temperatures below 9°C is usually required to fully cold harden plants. However, regardless of the amount of cold acclimation, the wheat plant must receive insulating snow cover to survive the cold prairie winters.

Vernalization. During the period of cold acclimation, the low temperatures also initiate in the plant a physiological response called vernalization.  During vernalization, the plant converts from vegetative to reproductive growth and the reproductive structures are developed.  Because of this vernalization requirement, winter wheat produces only leaves for both the main stem and tillers aboveground in the fall in preparation for winter.  The growing point and buds of both the main stem and tillers remain belowground, insulated against the cold winter temperatures. Once vernalization requirements are met, the growing point differentiates and develops an embryonic head.  At this time, wheat head size or total number of spikelets per head is determined.  What is important to note here is neither seedling growth nor tillering is required for vernalization to occur.  This process can begin in seeds as soon as they absorb water and swell.  Hence, late planted wheat that has not emerged prior to winter should be adequately vernalized.   Or in extreme conditions, vernalization may occur under cool spring conditions.

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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