VCR – Vegetable Crop Report – September 2nd, 2021

Temperature – Daytime temperatures are forecasted to stay around the low twenties over the next week. All regions remain above their GDD 10-year average.

Cabbage maggot is at its final threshold in the regions of Huron, Wellington, Simcoe, Peterborough, and Kemptville. In the overlap region of Wellington County European Corn Borer will be going through its third peak catch most likely within the next week. GDD data for each region is shown below.

Rainfall – Most regions are forecasted to have some rain over the weekend and continuing into the following week. So far Huron County is the only region that has experienced any rainfall in the month of September. Rainfall data for each region is shown below.

Crop Updates

Brassica Crops – Alternaria is becoming more widespread across the province. Depending on the Brassica crop grown, not all fungicides are labelled for use; see Table 1 below for fungicides registered on different Brassica crop groups. The second generation of cabbage maggot is underway across many Brassica growing regions. Diamondback moths, imported cabbageworms, and tarnished plant bugs are active. Avoid scouting or working in the crop when the crop is wet and start from the cleanest plantings first and move to plantings with known pathogens later in the day.

**Table 1.** Fungicides for Brassica Alternaria.

Celery – Conditions continue to be favourable for bacterial blight. Continue to scout for Cercospora and 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, aster leafhoppers, leafminers and aphids.

**Figure 1.** Bacterial blight of celery – August 2021.

Onions – Fields are continuing to lodge or have been windrowed and harvested already. Hopefully, conditions are favourable for harvest over the next couple of weeks. The 2021 Muck Crops Research Station Grower Field Day is September 9^th from 8:30 AM– 4:00 PM. Check out cultivar evaluations and research trials at 1125 Woodchoppers Lane, King, ON. This year, Haggerty Creek will be showcasing the Naio Oz and Korechi RoamIO robotic weeders at 10 AM, 12 AM and 2 PM at the Grower Field Day.

Pest Degree Day Forecasting

*NOTE: Data as of September 1, 2021

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*	2366	2202	1726	1444	1069	1879	2202	1314
Chatham-Kent*	2208	2046	1591	1317	898	1737	2046	1188
Norfolk**	2187	2027	1573	1299	883	1720	2027	1168
Huron***	2036	1881	1448	1184	777	1586	1881	1060
Wellington**	1983	1826	1391	1127	729	1530	1826	1003
Simcoe County***	2039	1879	1436	1171	774	1577	1879	1047
Durham***	2110	1953	1501	1243	841	1644	1953	1120
Peterborough	1912	1753	1312	1055	674	1452	1753	934
Kemptville***	2062	1906	1457	1186	788	1602	1906	1063
Sudbury***	1785	1642	1248	1015	642	1373	1642	902