Temperature – All regions continue to match or surpass their 10 year average GDD trend except Peterborough. After some cooler weather this past week daytime temperatures will run high again into the mid- to high- 20s. Eastern and Northern regions may also see some days in the high teens as well as nighttime temperatures occasionally dropping to the low teens.
Precipitation – Huron and Peterborough received more rain than their 10 year average cumulative precipitation levels for August. Essex, Chatham-Kent, and Wellington were slightly below their 10 year averages. Norfolk, Simcoe, Kemptville and Sudbury received well over half and Durham received just under half its 10 year average rainfall for August. Rain is expected to be scattered throughout next week across the province, sometimes with the risk of thunderstorms.
Brassica Crops – Imported cabbageworms, tarnished plant bugs and cabbage maggot are very active in some regions. Black rot has been observed in several fields but is not a prevalent as 2021. Alternaria is starting to become prominent in some fields. Multiple species of Alternaria including A. alternata, A. brassicae and A. brassicola can create lesions on different parts of Brassica crops including the marketable heads, leaves and sprouts. It is important to rotate fungicides from different FRAC groups to reduce the chance of fungicide resistance to Alternaria. An Emergency Use Registration (EUR) for SWITCH® 62.5WG Fungicide was approved from July 8th, 2022, until July 7th, 2023. For more details see this post:
Table 1. Products registered for use on broccoli, brussels sprouts, and cauliflower against Alternaria spp..
|Fungicide||FRAC Group (s)||Maximum Number of Applications|
|Bravo ZN/ZNC Echo 720||M5||1|
|Miravis Duo||3 / 7||2|
|Quadris Top||3 / 11||4|
|Luna Sensation||7 / 11||3|
|Switch 62.5 WG||9 / 12||3 (Emergency Use for 2022)|
Celery – Conditions continue to be favourable for bacterial blight. Continue to scout for Cercospora, Septoria, 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 and aphids.
Garlic – Planting season will commence over the next month. Early plantings have an increased chance of bolting and winterkill. When purchasing planting stock this fall, send some cloves for stem and bulb nematode testing prior to planting. Even cloves with an intact basal plate and no observable damage may have nematodes living inside.
Onions – Harvest is underway in many areas while many other areas are starting to lodge. The 2022 Muck Crops Research Station Grower Field Day is September 8th from 8:30 AM– 4:00 PM at the Muck Crops Research Station (Ontario Crops Research Centre – Bradford). Check out cultivar evaluations and research trials at 1125 Woodchoppers Lane, King, ON.
Pest Degree Day Forecasting
*NOTE: Data as of August 31st, 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|
*- Bivoltine region for ECB. First Peak Catch: 300-350 DD, Second Peak Catch 1050-1100 DD
**- Overlap region for ECB. First Peak Catch: 300-350 DD Second Peak Catch 650-700 DD, Third Peak Catch 1050-1100 DD
***-Univoltine region for ECB. Peak Catch 650-700 DD
Use these thresholds as a guide, always confirm insect activity with actual field scouting and trap counts.
Select a region below for the latest weather, crop and pest degree day information: