VCR – Vegetable Crop Report – September 1st, 2022

Temperature – All regions continue to match or surpass their 10 year average GDD trend except Peterborough. After some cooler weather this past week daytime temperatures will run high again into the mid- to high- 20s. Eastern and Northern regions may also see some days in the high teens as well as nighttime temperatures occasionally dropping to the low teens.

Precipitation – Huron and Peterborough received more rain than their 10 year average cumulative precipitation levels for August. Essex, Chatham-Kent, and Wellington were slightly below their 10 year averages. Norfolk, Simcoe, Kemptville and Sudbury received well over half and Durham received just under half its 10 year average rainfall for August. Rain is expected to be scattered throughout next week across the province, sometimes with the risk of thunderstorms.

Crop Updates

Brassica Crops – Imported cabbageworms, tarnished plant bugs and cabbage maggot are very active in some regions. Black rot has been observed in several fields but is not a prevalent as 2021. Alternaria is starting to become prominent in some fields. Multiple species of Alternaria including A. alternata, A. brassicae and A. brassicola can create lesions on different parts of Brassica crops including the marketable heads, leaves and sprouts. It is important to rotate fungicides from different FRAC groups to reduce the chance of fungicide resistance to Alternaria. An Emergency Use Registration (EUR) for SWITCH® 62.5WG Fungicide was approved from July 8th, 2022, until July 7th, 2023. For more details see this post:

SWITCH® 62.5 WG Fungicide label temporarily expanded via Emergency Use Registration to help manage Alternaria Leaf Blight in Brussels Sprouts, Broccoli, and Cauliflower in Ontario, Quebec, Nova Scotia, Prince Edward Island, and Newfoundland and Labrador

Table 1. Products registered for use on broccoli, brussels sprouts, and cauliflower against Alternaria spp..

Fungicide	FRAC Group (s)	Maximum Number of Applications
Bravo ZN/ZNC Echo 720	M5	1
Miravis Duo	3 / 7	2
Quadris Top	3 / 11	4
Fontelis	7	4
Sercadis	7	3
Luna Sensation	7 / 11	3
Switch 62.5 WG	9 / 12	3 (Emergency Use for 2022)

Celery – Conditions continue to be favourable for bacterial blight. Continue to scout for Cercospora, Septoria, Sclerotinia pink rot and celery leaf curl. Avoid scouting when leaves are wet as pathogens can spread easily on clothes/equipment throughout the field. Disc harvested blocks to reduce pest pressure and plant a cover crop to prevent soil erosion. Continue to scout for tarnished plant bugs and aphids.

Garlic – Planting season will commence over the next month. Early plantings have an increased chance of bolting and winterkill. When purchasing planting stock this fall, send some cloves for stem and bulb nematode testing prior to planting. Even cloves with an intact basal plate and no observable damage may have nematodes living inside.

Onions – Harvest is underway in many areas while many other areas are starting to lodge. The 2022 Muck Crops Research Station Grower Field Day is September 8th from 8:30 AM– 4:00 PM at the Muck Crops Research Station (Ontario Crops Research Centre – Bradford). Check out cultivar evaluations and research trials at 1125 Woodchoppers Lane, King, ON.

Pest Degree Day Forecasting

*NOTE: Data as of August 31st, 2022

County	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*	2344	2184	1728	1453	1075	1876	2184	1322
Chatham-Kent*	2152	1997	1557	1291	881	1700	1997	1167
Norfolk**	2113	1961	1523	1252	838	1667	1961	1125
Huron***	1916	1767	1341	1080	685	1478	1767	956
Wellington**	1867	1720	1297	1037	646	1434	1720	919
Simcoe County***	1903	1755	1335	1075	686	1472	1755	954
Durham***	2027	1874	1442	1177	770	1582	1874	1051
Peterborough	1814	1666	1243	989	606	1380	1666	869
Kemptville***	2027	1872	1442	1182	774	1578	1872	1057
Sudbury***	1703	1571	1184	941	564	1311	1571	826