Agronomy Update – July 4

Hi everyone,

I’m back after a great experience at the World Potato Congress in Australia last week.  I will have a couple of articles on the WPC in the next issue of the Potato News to share some highlights of the Congress.  It was well attended (more than 1000 delegates from more than forty countries), with an interesting collection of presentations and post-conference tours.  It was a pleasure to present on some of the work that we’ve been doing here in PEI through AIM, Living Labs, and more that focus on both improving yields and profitability while also prioritizing sustainability.


Pest and Disease Update:

Aphid Alert:

  • The first week of aphid collections began last week.
  • Average number of aphids collected was 3.1 aphids per traps for the first week.  This is higher than our first week of collection in 2023.
  • The majority of aphids collected so far are “other aphids” and buckthorn aphids.  These are non-colonizing aphids that are more transient in nature but can carry virus if they visit infected plants before landing in your field.  A small number of potato aphids were collected in Prince County.
  • No green peach aphids were collected in PEI last week; however, green peach aphids have been detected two weeks in a row in Maine, earlier than last year.
  • An online data platform for aphid data is being developed by the PEI Department of Agriculture.  We hope to have that available to share soon.
  • The number of participating growers in aphid alert is up this year, with better coverage of the Island
  • All seed producers should be following a consistent spray schedule with a minimum of 2L of oil per week plus aphicides while aphid numbers are high. 


Spore Trapping:

  • Collections under both the Spornado and Airspore programs began this week.
  • No late blight spores were detected in PEI this week.  No spores were detected in either NB or Maine as well.
  • We have 12 sites across PEI this year under the Spornado program as an “early-warning network” for late blight and grey mold.  This program is funded by the PEI Agri-Watershed Partnership.
  • Alternaria spores (early blight and brown spot) have started high at a couple of locations in West Prince already but without many detections elsewhere in the province.  Alternaria numbers have generally progressed from west to east in previous years.  With the crop largely being in rapid growth and ahead of normal, growers are recommended to ensure they get fungicide targeting early blight/brown spot on now ahead of row closure, to ensure sufficient coverage on the lower leaves before full canopy.
  • There was a small number of Bortrytis (grey mold) spores identified earlier this week; however, with the warmer and drier weather this week and in the forecast, concern for grey mold is low.


Additional Pest/Disease notes:

  • There have been multiple reports of large numbers of European corn borer egg masses this week in West Prince.  Growing degree-days (GDD) are trending ahead of average this year, especially in West Prince.  Some egg masses are already at blackhead stage and sprays are going on.
  • Lots of catch-up on spraying happening this week after challenging conditions to spray last week.  Some reports of significant weed pressure so far, both grasses and broadleaf species.  A reminder that post-emergence application of Sencor is most effective mid-day on sunny days, according to the label.  If grasses are the primary weed issue, consider a tank-mix with a grass targeting herbicide such as Arrow.
  • Colorado potato beetles are present in many fields, but systemic insecticides appear to be working well in most fields, with highly levels of mortality observed.  In the last few years, we’ve seen that the effectiveness of the neonic (Titan/Actara) insecticides seems to be reduced after 60 days after planting, so for early planted acres, key an eye on CPB the next couple of weeks.
  • Under AIM, we are looking for growers to submit samples of early blight and brown spot as part of a fungicide resistance project with Dr. Rick Peters at AAFC.  If you have suspected early blight/brown spot symptoms, please contact me to arrange for collection of leaf samples.
  • There have been isolated reports of emergence issues, primarily related to identified issues with specific seed lots.  Emergence in the majority of fields appears consistent and even, with plants growing vigorously in the last 10 days.


June Weather Totals:

 Bethany tallied up rainfall and GDD totals from May and June across the Island:

Table 1: Rainfall amounts for the month of June (current year 2024 vs historical records 1981-2010)

  Rainfall (mm)      
Location June 2024 Historical 1981-2010 Difference Cumulative

May + June


Cumulative May + June Historical
O’Leary 172.4 84.8 87.6 192.6 187.7
Summerside 185.4 91.7 93.7 203.8 190
Charlottetown 83.9 98.8 -14.9 111.3 189.8
Souris 106.4 100.9 5.5 149.2 194


Table 2: Growing Degree Days for the month of June (current year 2024 vs historical records 1981-2010)

  Growing Degree Days (GDD)      
Location June 2024 Historical 1981-2010 Difference Cumulative May + June


Cumulative May + June Historical
O’Leary 344 284 60 503.5 408
Summerside 274 285 -11 447.4 428
Charlottetown 341 286 55 493.5 424
Souris 307 273 34 443 410


Substantial rains in June in Prince County has made up the deficit from May, but Eastern Queens and Kings County are running a bit behind on total rainfall.  West Prince is also running significantly ahead on GDD so far, more so than the rest of the province; that being said, all parts of the province are ahead of average on GDD so far.


Plant Diagnostic Testing Update:

The following update has been provided by the PEI Analytical Lab:  Due to unforeseen staffing shortages, the plant diagnostic section of PEI Analytical Laboratories is currently closed and will not be receiving samples until further notice.  Please do not hesitate to contact the lab with any questions or inquiries on how to proceed with alternative measures at 902-620-3300. An update will be made mid-August on the status of this service. PEI Analytical Laboratories apologizes for any inconvenience this may cause and remain committed to helping our clients. 

You can also reach out to me with any questions on plant health and I’m happy to help connect you with the right resources to meet your needs.


Living Labs BBQs next week:

Mark your calendars! Join us next week for the Living Lab – PEI field tours and free BBQs. Open to all PEI producers and Living Lab partners. We look forward to seeing you there and sharing some of the farmer-led research being done in PEI this year!

➡️ Monday, July 8th: Souris
11 a.m. 
Wetland Tour at

(46.35041, -62.28725)

12 p.m. BBQ at Souris Wildlife, 1358 Souris Line Rd, Souris

➡️ Tuesday, July 9th: Kinkora
11 a.m.
 Cover Crop Tour at

(46.33941, -63.59105)

12 p.m. BBQ at Smith Farms, 1010 Newton Rd, Kinkora

➡️ Thursday, July 11th: West Prince
11 a.m.
 Legume Tour at

(46.74365, -64.13847)

12 p.m. BBQ at Fox Island Elite Seed Farm, 269 Fox Island Rd

Tours on Tuesday and Thursday will include stops at trial fields under my direction as part of AIM and Living Labs.  I would encourage everyone to come out!

Have a great rest of the week,