VCR – Vegetable Crop Report – May 27th, 2021

Temperature – Day temperatures are forecasted to range from mid-teens to low-twenties based on region.

Nighttime temperatures are forecasted to be in the high single digits to low teens for most regions. The Growing Degree Day values have continued to increase faster than the previous 10-year averages, especially in the past week. Degree Day data for each region is shown below.

Rainfall – The forecast mostly sunny or partly cloudy for a majority of regions until Wednesday, June 2nd. Wrapping up with May, there has been very little rain in most regions, with most being behind by over 30mm. Precipitation data for each region is shown below.

Crop Updates

Brassicas – Head brassicas are establishing well. Imported cabbageworms, flea beetles and even diamondback moths are active. Observe the roots of wilted transplants and look for wireworms or cutworm larvae. Check stunted plants for wirestem. Seedcorn maggot has reached the threshold for first generation emergence and cabbage maggot will be emerging soon in most regions across the province and is likely already active in Essex and Chatham-Kent.

Brassica transplant with constricting of the stem above the soil line due to wirestem Rhizoctonia

Celery – Transplants are establishing well, and most fields have been planted across Southwestern Ontario. The threshold for aster leafhopper has been reached in Essex, Chatham-Kent, Norfolk, Huron, Wellington, Simcoe, Durham, Peterborough, Kemptville, Sudbury and every county has had enough growing degree days for tarnished plant bug.

Garlic – The most advanced plants have 9 leaves, but the majority have 6 across the province. Plants in warmer areas, such as Essex are starting to scape which is early. Leek moth trap counts are low in areas where the moth has established.

Garlic scapes emerging in Essex County – Dennis Meleg

Onions – Seeding and transplant onion planting is mostly complete across the province. Seeded onions are growing slowly in areas without adequate moisture and are anywhere from the flag to 1st leaf stage while most fields are past the first leaf stage. Transplants have established well in fields that have received adequate levels of moisture. Both onion and seedcorn maggot flies are active across most regions. If wilting is observed, dig up the roots and look for larvae of maggot flies, or wireworms to confirm the insect that caused the damage.

Carrots – Dry conditions continue in most areas of the province with the majority of the carrots now seeded. Irrigation is ongoing and might be needed to ensure consistent germination this season.

Potatoes – With the bulk of potato planting wrapped up, we could use a little bit of rain. Many fields have adequate moisture below but the top is quite dry. Don’t be surprised with reduced activity from pre-emergent herbicides this year unless you can irrigate them or we receive some rain to activate them. Keep an eye out for emergence issues.

Pest Degree Day Forecasting

*NOTE: Data as of May 26th, 2021

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*	576	507	316	224	130	374	507	188
Chatham-Kent*	523	457	290	208	107	340	457	174
Norfolk**	500	436	270	186	90	321	436	151
Huron***	466	408	266	194	102	307	408	163
Wellington**	414	354	211	141	64	252	354	112
Simcoe County***	443	380	226	152	72	271	380	122
Durham***	427	367	209	144	68	255	367	119
Peterborough	400	338	187	121	52	231	338	95
Kemptville***	500	438	266	180	85	319	438	146
Sudbury***	354	304	187	136	66	221	304	113