VCR – Vegetable Crop Report – May 18th, 2021

Temperature – Day temperatures are forecasted to be mid-high teens all the way to the high twenties depending on the region.

Nighttime temperatures are forecasted to be in the low teens for most regions. The Growing Degree Day values continue to increase well above their 10-year average values in most regions. Degree Day data for each region is shown below.

Rainfall – A majority of regions are well behind the 10-year average for rainfall in the month of May. There are chances of rain and thunderstorms for the remainder of this week and into the weekend in many regions. Precipitation data for each region is shown below.

Crop Updates

Brassica Crops – Most transplants are showing frost damage across the province with the outer most leaves turning purple or yellow. While it has not been warm enough for cabbage maggot fly to reach it’s 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 can be found at:

Carrot – Early seeded carrots have survived some early frost events and are growing well. As we are now into the bulk of carrot seeding, conditions are fairly dry. Irrigation may be required to ensure even germination and emergence as well as to activate any pre-emergence herbicides. If you were unable to attend our carrot IPM scout training last week here is a YouTube video link for you to catch up on or refresh your memory:

Garlic – Most crops across the province overwintered well and there were little problems with emergence. With the warm weather in March and April, many fields are much more advanced than this time last year. Hard frosts in April when plants were past the 5 leaf stage caused yellowing of older leaves and in many regions plants are showing some sort of tipburn. Most plants are past the 5th leaf stage, so avoid applying nitrogen to reduce the amount of rough bulbs at harvest as well as to encourage longer storage life. The nightly lows have not been above the 9.5C required for leek moth in most regions, however, leek moth has been detected and is likely active across the province in sheltered areas that experienced warmer night temperatures. If any wilted plants are found, dig up plants with a trowel and inspect roots for maggot fly larvae or wireworms. If your garlic already shows signs of leaf damage due to an insect, please send photos to travis.cranmer@ontario.ca.

Leek Moths caught on sticky cards in Renfrew County

Onions – The cool, dry weather has made it difficult for some seeded fields to germinate evenly and transplants have been slow to establish. Once seeded onions have emerged, count out 25 plants per row and put a marker at each end and record the number of plants every week. These damage plots will be valuable to monitor the amount of damage due to maggot flies or other pests. The threshold for seedcorn and onion maggot fly have been reached in all counties below except for Sudbury. If you were unable to attend the Onion IPM scouting workshop, a recorded version can be found at:

Potatoes – Early planted potatoes are emerging and growing well with this warm weather. The bulk of potatoes are currently being planted.

Tomatoes – Planting is underway. Scouting for early season pests should be started as soon as transplanting is complete. Be sure to scout for early season insect pests such as cutworms, wireworms (pictured below) and Colorado potato beetle. If you were unable to attend the Tomato and Pepper IPM scouting workshop, a recorded version can be found at:

Pest Degree Day Forecasting

*NOTE: Data as of May 17th, 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*	419	359	195	121	54	244	359	94
Chatham-Kent*	369	312	172	108	38	213	312	83
Norfolk**	352	297	158	92	26	200	297	66
Huron***	317	269	153	99	38	185	269	78
Wellington**	278	227	111	59	12	143	227	39
Simcoe County***	302	249	121	65	15	157	249	44
Durham***	286	235	104	57	11	140	235	41
Peterborough	267	214	90	42	3	125	214	25
Kemptville***	353	299	154	86	22	198	299	61
Sudbury***	221	180	90	56	17	114	180	42