VCR – Vegetable Crop Report – August 28th 2025

Welcome to the last VCR of 2025!

Currently most counties are slightly above their 10 year average GDD, with Norfolk, Sudbury, Timiskaming, and Thunder Bay trending at their 10 year average.

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Crop Updates

Brassica Crops – Imported cabbageworms and tarnished plant bugs are active in some regions. 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. For registered fungicides on Brassica Alternaria on broccoli, Brussels sprouts, cabbage and cauliflower, see the Ontario Crop Protection Hub

Garlic – Results from the past 3 years of planting date trials seem to indicate that the later garlic is planted, the greater the amount of risk there is to losing yields at harvest the following July. To determine if planting earlier would result in winterkill or have negative impacts on yield, a planting date trial was set up in Dashwood, ON in 2022 with seven planting dates starting August 30^th and continuing roughly every three weeks until December 6^th, along with a single planting date in April 2023. Cloves were planted on similar dates in 2023-2024 and again in the past year. In all three years, this early planting date had best winter survival, and the most leaves emerged prior to snow cover / the ground freezing. In the first two years the earliest dates also had the highest yields (Figure 2). The full results of this trial will be posted as a report on the www.ONvegetables.com blog soon and discussed during the garlic session at the Ontario Fruit and Vegetable convention in February 2026.

**Figure 1** – Spring plant emergence from various planting dates with earlier planting dates showing more advanced growth early in the spring. Left column 2022-2023; middle column 2023-2024; and right column 2024-2025.

**Figure 2** – Average bulb weight at harvest from cloves planted at various planting dates in 2022-2023 and 2023-2024. Results form 2024-2025 will be posted on the www.ONvegetables.com in the upcoming months.

Onions – Harvest continues. The 2025 Muck Crops Research Station Grower Field Day is September 4th 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

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
Bruce***	1767	1622	1215	972	648	1344	1622	860
Chatham-Kent*	2136	1977	1525	1256	891	1668	1977	1128
Durham***	2009	1861	1444	1184	838	1580	1861	1062
Essex*	2279	2118	1659	1378	994	1807	2118	1246
Huron***	1919	1767	1347	1097	762	1481	1767	982
Kemptville***	1998	1852	1432	1174	832	1568	1852	1056
Lambton**	2094	1936	1493	1229	876	1636	1936	1107
Middlesex**	2109	1954	1512	1241	881	1654	1954	1115
Norfolk**	2022	1866	1423	1157	808	1565	1866	1034
Peterborough	1891	1743	1324	1072	735	1459	1743	955
Renfrew	2005	1862	1450	1200	866	1584	1862	1083
Simcoe***	1923	1775	1364	1112	783	1496	1775	998
Sudbury***	1629	1500	1131	909	604	1249	1500	805
Thunder Bay	1452	1328	978	762	469	1090	1328	659
Timiskaming***	1536	1411	1062	851	557	1173	1411	749
Wellington Centre**	1871	1723	1305	1052	719	1441	1723	937
Wellington North**	1886	1739	1320	1076	742	1455	1739	962