Temperature: After cooler weather the past few weeks, GDD have caught up or greatly surpassed the 10 year average in all counties. Temperatures are expected to rise over the weekend before cooling and returning into the teens or low 20s into next week.
All regions except Sudbury are at threshold for onion and seedcorn maggot. Essex, Chatham-Kent and Norfolk counties are at threshold for carrot rustfly. All counties except Wellington, Simcoe, Durham and Peterborough are at threshold for tarnished plant bug. Durham and Kentville are at threshold for carrot weevil and Essex has also reached it’s threshold for aster leaf hopper. Click here to go to the full pest threshold table.
Precipitation: Kemptville has now surpassed their 10 year precipitation average. Essex, Chatham-Kent, and Norfolk are catching up to their May 10 year averages. All other counties, and especially Sudbury, are lagging behind. Heavy rain, and in some regions thunderstorms, are forecasted over the weekend and more rain may come mid next week.
Brassica crops – Transplanting continues. Some counties that experienced frost may see the older, outer-most leaves turn yellow and wilt over the next week. Dig up wilted plants and inspect roots for maggots as seedcorn maggot flies has been active and eggs laid over the past week the past week will be hatching.
Carrots – Some early seeded fields in SW Ontario have emerged. In Central Ontario some fields have been seeded, with the bulk of the seeding to be done in the next week or two. Carrot rust fly is nearing emergence in the Southern regions of the province.
Garlic – Leek moth has been active in most areas across the province and eggs laid over the past week will be hatching into larvae over the next week. Inspect the inner most leaves and look for feeding damage from leek moth larvae. These leek moth larvae will be responsible for the main peak flight generally experienced in the first half of June. Continue to dig up wilted plants and look for seedcord maggot larvae, wireworms or millipedes. Most plants are past the 5th leaf stage, so most nitrogen should be applied by now for the greatest impact. Avoid applying nitrogen to older plants to reduce the amount of rough bulbs at harvest as well as to encourage longer storage life.
Onion – Most transplanted and direct seeded onion fields finished planting over the past week with the majority of direct seeded fields in the flag or first true leaf stage. Onion maggot flies have reached their threshold for the first-generation emergence in most counties and damage from early season activity will likely be observed shortly. Dig up wilted plants and inspect roots for onion maggot larvae.
Potatoes – A cool spring has resulted in slow emergence. Early fields in SW Ontario have emerged. With excellent planting conditions last week a large portion of the main crop was planted. The light rains have paused planting temporarily but field conditions remain quite good.
Tomatoes – Planting is underway. Scouting for early season pests, such as Colorado potato beetle, black cutworm and wireworm, should be started as soon as transplanting is complete. If you were unable to attend the Tomato and Pepper IPM scouting workshop on May 4th, a recorded version can be viewed below:
Pest Degree Day Forecasting
*NOTE: Data as of May 18, 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: