VCR – Vegetable Crop Report – May 12th, 2022

Temperature: Temperatures continue to rise over the weekend before dropping back into the teens next week. Most counties are at or marginally behind their 10-year GDD averages with the exception of Huron and Durham counties which are slightly ahead. The pest threshold has been reached for onion maggot in Essex and seedcorn maggot is now at threshold in Essex, Chatham-Kent and Norfolk counties.

Precipitation: Most counties may see some rain over the weekend with the possibility of thunderstorms. Most did not experience any significant rainfall over the past week.

*Note: The 10-year average GDD calculation has changed to better reflect the current weather trends. Last week’s GDD graphs have been updated.

Crop Updates

Brassica crops – Transplanting is well underway. While it has not been warm enough for cabbage maggot fly to reach it’s first generation growing degree threshold in any county, seedcorn maggot fly is active in most regions. Dig up wilted transplants and inspect roots for insect damage. If you were unable to attend the 2022 Brassica Crops IPM Scout Training workshop, a recorded version can be viewed below:

Celery – Transplanting is underway across the province. Ensure that there is adequate moisture to get good crop establishment.

**Figure 1** – Celery ready to be transplanted – May 10^th, 2022.

Garlic – Plants are at an average of 4-7 leaves. Leek moths are active in most regions with the warm night temperatures and will be laying eggs over the next week. Seedcorn maggot damage has been observed in SW Ontario and has reached its first generation threshold in Essex, Chatham-Kent and Norfolk counties. Dig up plants that have wilted leaves to look for seedcorn maggot larvae, wireworms or millipedes.

**Figure** 2 – Seedcorn maggot larvae found feeding on a wilted garlic plant May 10^th, 2022 – Kristen Obeid

Onion – Onions are still being transplanted and direct seeded onions planted last week are starting to emerge in fields with adequate soil moisture. The threshold for the first generation of onion maggot has been reached in Essex county.

Pest Degree Day Forecasting

*NOTE: Data as of May 11, 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*	292	245	124	73	30	160	245	55
Chatham-Kent*	245	202	98	55	19	129	202	41
Norfolk**	244	204	102	55	17	133	204	39
Huron***	230	193	103	63	26	128	193	48
Wellington**	196	161	73	36	12	99	161	28
Simcoe County***	194	158	74	36	10	98	158	24
Durham***	222	182	86	45	10	114	182	29
Peterborough	193	158	71	37	7	96	158	25
Kemptville***	220	177	83	46	11	107	177	32
Sudbury***	96	78	37	20	7	49	78	15