By: Faye Bouchard PAg, MSc, Crop Protection Laboratory Manager
256 Disease and Disorder Diagnosis Samples
Our most common disease diagnoses in 2016 were root rots and herbicide damage. While most of the root rot samples were from pulses, we did see some cereal root, crown and foot rot samples later in the season (see Photo 1). Premature ripening is one of the symptoms associated with this disease complex, but confirmation was achieved by looking for brown lesions on the stem, crown, sub-crown internode, and/or roots. We were also usually able to isolate Cochliobolus or Fusarium from these samples. Thanks to many of our Plant Industry specialists for their help with samples this season, as well as our Provincial Specialist for Plant Disease, Barb Ziesman.
13 Insect Identifications, 29 Weed Identifications, plus weed seeds for Herbicide Resistance Testing
Thanks to assistance from our Insect Specialist Scott Hartley, IPM Agrologist Danielle Stephens and Weed Control Specialist Clark Brenzil, we were able to provide insect and weed IDs for clients as usual this season.,/p>
While we don’t receive as many insect and weed ID samples as we do disease diagnostic samples, we are expecting many more weed seed samples for herbicide resistance testing. It’s not too late to submit samples, bearing in mind some important points:
Sampling for weeds
- If possible, collect only mature, healthy seed from the suspect plants. Green or diseased seed will not germinate properly and will impede the diagnosis or make testing impossible.
- A minimum of 2,000 seeds per herbicide group is desirable. When there is a need for several groups of herbicides to be tested, the number of seeds should be increased accordingly.
- Collect seed from specimens that appear to have survived the herbicide application. If other labelled weeds have been controlled in the area, there is stronger reason to suspect resistance.
- Note the crop from the current and the previous four years, the herbicide(s) used and its rate of application, the timing of application (month, year, growth stage of crop, growth stage of weed), climatic conditions around the time of application, the weed's distribution, and level of control.
- Do not submit seed that has been treated with a pre-harvest herbicide.
- Indicate the Herbicide Resistance Group(s) that you want to be tested.
- Samples are processed on a first come, first serve basis with the duration of the test varying based on the group and type of weed being tested.
- Complete and include the online Herbicide Resistance Diagnostic Lab Form.
Packaging and handling
- Allow seeds to air dry before shipping. This is done by placing the seeds in paper bags and allowing them to air dry for a few weeks in a dry environment. This prevents mould developing in shipment. It is not critical to get the samples to the laboratory quickly, as testing will not commence until January so that seeds have time to break their dormancy period.
- Seed should be relatively clean with as little foreign material as possible.
- Once the seeds are dry they should be packaged in any durable container including strong plastic bags and then placed in sturdy cardboard containers (or equivalent) prior to shipping to the laboratory.
Check out our Herbicide Resistance Testing web page for information and forms.
Payment Options at the Crop Protection Laboratory
We now accept credit card payment at the lab, so if you have an old invoice yet to be paid, please contact us at 306-787-4998, with your invoice number, customer number and credit card handy. Stay tuned for more exciting changes to our lab reporting and payment options next season.
199 DED Samples
As usual, Dutch elm disease (DED) has been keeping surveyors and homeowners on their toes. There were 199 DED sample submissions to the Crop Protection Laboratory. Out of these submissions:
- 55 samples (28 per cent) tested positive for Ophiostoma novo-ulmi, the pathogen that causes DED. An additional 14 trees were identified as positive without a sample and reported to the DED summer student.
- 17 samples (9 per cent) tested positive for Dothiorella ulmi, the pathogen that causes dothiorella wilt. This condition has symptoms that are similar to DED.
- 127 samples (64 per cent) tested negative for DED or dothiorella wilt
DED testing is conducted free of charge for Saskatchewan residents. The Crop Protection Laboratory is no longer accepting samples for 2016 testing, but will resume testing June 1, 2017. The Crop Protection Laboratory has online directions outlining how to take a representative sample.
What to do when the tree is tested positive for DED
- Dutch elm disease is provincially regulated under The Forest Resources Management Act and is federally regulated under The Plant Protection Act. Trees confirmed to have DED (a positive test result) are to be removed immediately and the wood must be promptly disposed of at the nearest elm tree disposal site. The Saskatchewan Ministry of Environment will be notified of any positive results.
Approximately 210 FHB Samples and Approximately 120 Clubroot Soil Samples – In Progress
The Saskatchewan Fusarium Head Blight Survey monitors the severity and spread of fusarium head blight (FHB) within the province and determines the Fusarium species responsible for infection. Saskatchewan Crop Insurance adjusters collect 50 heads per field from 10 fields within their regions, when the crop is in the early milk to early dough stages. Samples are sent to the Crop Protection Laboratory for species identification and a disease severity rating from a subsample of 30 heads per field.
Sample analysis is currently underway (preliminary data as of Oct. 7, 2016). Of the 128 samples processed to date (out of approximately 210 samples expected for the survey), 89 per cent of the 27 completed barley samples, 98 per cent of the 42 completed durum samples, and 100 per cent of the 59 completed common wheat samples had at least one suspected fusarium damaged kernel.
The average preliminary (based on visual assessment) mean severity ratings (FHB index) are 1.3 per cent for barley, 3.6 per cent for durum, and 2.1 per cent for common wheat. Symptoms of septoria glume blotch were observed in 31 per cent of the samples, ergot was observed in 8 per cent of the samples, wheat midge was observed in 24 per cent of the samples, and aphids were observed in 8 per cent of the samples. Survey samples are still being analyzed and results will be made available this winter.
We are also currently processing about 120 soil samples collected through the provincial canola disease survey. These samples will be tested for the presence of the clubroot pathogen, Plasmodiophora brassicae, using qPCR.