VCR – Vegetable Crop Report – September 10th, 2020

The weather and pest forecasting dashboard is live! Check out values specific to your region at https://onvegetables.com/weather-dashboard/

Temperature – Temperatures remain stable in the high teens and low 20s throughout the week though some regions in southern Ontario may see higher temperatures over the weekend with the humidex. Night temperatures are forecasted to be in the single digits in some areas and Environment Canada has put out a frost advisory for northeastern and central Ontario. Cabbage maggot is at threshold in Huron, Wellington, Simcoe, and Peterborough. Degree day data for each region is shown below.

Rainfall – Many regions received rain in the past week. Huron county has now surpassed the 10 year average and many other regions have received around half their 10 year averages. There is a chance of showers across Ontario over the weekend and again towards the end of next week. Precipitation data for each region is shown below.

Crop Updates

Brassica Crops – Downy mildew has been found in fields without any preventative fungicide applications. Alternaria is becoming widespread. Keep spore levels low in the area by incorporating blocks as soon as they are harvested. Keep an eye open for late season flushes of thrips.

Carrot – The carrots have been loving this past stretch of cooler temperatures and are bulking up by the day. Unfortunately leaf blights have also been enjoying it so remain vigilant with scouting and fungicide applications. Although we haven’t had many reports of it yet, Sclerotinia white mould will also be increasing with this weather. Look for fluffy white growth at the bottom of the canopy on older leaves.

Celery – Harvest is underway. When scouting late in the season, avoid moving through the crop when the leaves are wet as pathogens can spread easily on clothes/equipment throughout the field. Scout for aphids, tarnished plant bugs, aster leaf hoppers, and Leafminers.

Cucurbits – Sustained wet soil conditions are conducive to infection by Oomycetes such as Phytophthora which can lead to extensive damage in the field (Figure 1), and can lead to storage rots. Workers harvesting pumpkins and squash with Phytophthora infections should sanitize their hands after handling infected fruits before handling uninfected fruit. Management of Phytophthora infestation in cucurbit fields requires a long (4-5 year) rotation. Listen to discussion of Phytophthora “Phytophthora Phthoughs”, and the final weeks of pumpkin production “Pumpkin Decisions in the Final Stretch” at the Great Lakes Vegetable Producers Network: https://www.glveg.net/listen.

Figure 1. Pumpkins infected with *Phytophthora capsici* causing Phytophthora blight, Norfolk County, Sept 8.

Onions – Most fields have started to lodge or have been harvested already. No downy mildew outbreaks have been confirmed. Continue to scout for thrips in later fields that are still green. The 2020 Muck Crops Research Station Variety Trials Evaluation Days finish Friday, September 11. Please call the Muck Station at 905-775-3783 or E-mail Shawn at sjanse@uoguelph.ca to book your timeslot. Timeslots are available from 8:30AM to noon or 1:00 to 4:00 with a maximum of 10 people per time slot. Access to the Muck Station will be restricted and health protocols will be enforced.

Potatoes – Late fields are bulking and senescing while harvest ramps up with storages beginning to be filled.

NOTE: Data as of September 9th, 2020

Pest Degree Day Forecasting

Pest	Carrot Rust Fly	Onion Maggot	Carrot Weevil	Aster Leafhopper	Tarnished Plant Bug	Cabbage Maggot	Seedcorn Maggot	European Corn Borer
THRESHOLD	329-395, 1399-1711	210-700, 1025-1515	138-156, 455+	128+	40+	314-398, 847-960, 1446-1604	200-350, 600-750, 1000-1150	See legend below
Essex*	2449	2277	1807	1531	1148	1956	2277	1401
Chatham-Kent*	2266	2100	1655	1389	965	1795	2100	1262
Norfolk**	2242	2077	1621	1355	934	1764	2077	1227
Huron***	1989	1840	1427	1169	765	1559	1840	1044
Wellington**	1982	1827	1410	1157	762	1543	1827	1036
Simcoe County***	2019	1867	1454	1201	807	1587	1867	1079
Durham***	2160	2003	1574	1318	910	1708	2003	1194
Peterborough	1959	1802	1380	1124	725	1513	1802	1001
Kemptville***	2105	1951	1525	1271	871	1658	1951	1149
Sudbury***	1782	1647	1268	1034	665	1388	1647	921