VCR – Vegetable Crop Report – May 5th, 2022

The Vegetable Crop Report is back for another season! We hope that your field season is off to a good start despite the cool wet weather we have had in many regions over the past month.

Temperature: Temperatures are on the rise next week with a forecast of high teens and even low to mid-twenties in some areas. *UPDATE (12/05/2022): The 10-year average GDD calculation has changed to better reflect the current weather trends. Durham, Peterborough, and Kemptville are meeting their 10 year GDD averages however all other counties are lagging behind.

Rainfall: Little rain is forecasted over the next week with full sun expected in most counties over the next 7 days. Most counties are lagging behind their 10-year precipitation averages for March and April with the exception of Huron, Kemptville and Sudbury which surpassed them in March.

Crop Updates

Brassica Crops – A significant portion of transplanting has been postponed to this week as many regions have seen some very cool nights. Some fields that were planted are showing frost damage with the outer most leaves turning purple or yellow. While it has not been warm enough for cabbage maggot fly to reach its first-generation growing degree threshold in any county, seedcorn maggotfly is active in most regions. If you were unable to attend the Brassica Crops IPM scouting workshop, a recorded version here:

Garlic – The amount of winterkill over the 2021-2022 winter has been high. Many fields were too wet to be planted in September and October and later plantings did not have much time to produce good root establishment before the ground froze. Many fields that were planted were saturated which may have resulted in more frost heaving and injury. Areas experiencing hard frosts with night-time temperatures below -4°C are showing tip burn on the older leaves. Overall, plants are at the 4-6 leaf stage in more southern regions. Now is the time to set up leek moth traps as adult moths emerge from overwintering sites and are looking for a place to lay eggs once the night temperatures remain above 9.5°C for two consecutive nights. Some areas with microclimates may have already had some adult leek moth activity as seen from this picture taken in Guelph, ON. If wilted plants are seen while scouting, dig up the plant and inspect the roots for wireworms or seedcorn maggot larvae. If your garlic already shows leaf damage due to an insect, please send photos to travis.cranmer@ontario.ca.

**Figure 1.** Three leek moth adults were caught in a pheromone trap April 26th near Guelph where recorded temperatures failed to remain above 9.5°C for two consecutive nights.

Onions – The cool, wet weather has slowed germination and made transplants slow to establish in fields that have been planted. Once the flag leaf has emerged, count out 25 plants per row and put a stake at each end. Record the number of plants over the next few weeks and monitor for damage due to maggot flies, damping-off or cold weather. Register now for the Onion IPM Scouting workshop on Thursday, May 12th. Onion insect and pathogen scouting will be the focus of the in-person and virtual workshop.

Click here to register for the Onion IPM Scouting workshop.

More Upcoming Workshops:

Carrot – Register for the upcoming Carrot IPM workshop on May 12^th.

Cucurbits – Register for the upcoming Cucurbit IPM workshop on May 18^th.

Sweet Corn – Register for the upcoming Sweet Corn, Peas and Beans IPM Workshop on May 11^th

Pest Degree Day Forecasting

*NOTE: Data as of May 4, 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*	222	182	83	45	16	111	182	32
Chatham-Kent*	180	144	61	31	9	85	144	22
Norfolk**	176	144	65	32	9	89	144	22
Huron***	154	124	55	29	9	73	124	20
Wellington**	134	106	40	16	5	58	106	12
Simcoe County***	135	106	43	18	2	60	106	10
Durham***	159	125	50	22	3	71	125	13
Peterborough	139	111	45	24	5	63	111	17
Kemptville***	160	124	51	27	4	68	124	18
Sudbury***	58	45	15	6	0	24	45	3