Temperature – High temperatures this past week allowed for Growing Degree Day values to catch up or surpass 10-year average values in all regions with the exception of Kemptville, which still lags marginally behind. Cooler temperatures are expected over the weekend before rising again towards the end of next week for most regions. Onion Maggot, Aster Leafhopper and Tarnished Plant bug thresholds have now been triggered in all regions. Carrot Rust Fly thresholds have been reached in Sudbury. Seedcorn Maggot thresholds are triggered in Essex and Sudbury, while Cabbage Maggot thresholds have been triggered in Huron, Wellington, Simcoe, and Durham counties, Peterborough, as well as Kemptville. Degree day data for each region is shown below.
Rainfall – Huron and Simcoe counties accumulated large amounts of rain yesterday and have now received around half the expected 10-year average value for June. No rain is forecasted for any region in the upcoming week. Precipitation data for each region is shown below.
Asparagus – Harvest is wrapping up for this year’s asparagus crop. Fluctuating temperatures have encouraged Stemphylium purple spot in many areas. Some fields have high incidence so inoculum levels should be assumed to be high. Asparagus should be scouted to determine when spray programs should begin for Stemphylium and for rust.
Brassica Crops – Flea beetles, cutworms and imported cabbageworms are active. Cabbage maggot has reached it’s degree day threshold in all regions except for Sudbury.
Carrot – Carrots are almost all seeded now and most have started to emerge. Hopefully the emerged carrot survived the storm and winds on Wednesday night. Carrot weevil are active right now and laying eggs so scout on the field borders and determine if the numbers are at threshold.
Celery – Aster leafhopper and tarnished plant bugs are active and thresholds have been reached in all regions
Cucurbits – Cucumber beetle continues to cause direct damage in many areas and vine crops should be scouted for these. Thresholds are low for this pest because they carry the causative agent of bacterial wilt. Cucumbers and melon are more susceptible to bacterial wilt, and pumpkins and squash are more attractive to cucumber beetle. If there are beetle emergences in your area, be alert for these during their second emergence later this summer and consider planting trap plants or indicator plants.
Garlic – The number of adult leek moths trapped has been down over the past two weeks and it’s likely that the second flight will be occurring shortly. Target the next wave of leek moth larvae a week after the next peak of adults trapped. Scapes are starting to emerge across Ontario in ‘Music’ and other hard neck cultivars.
Leafy Greens – Cutworms pressure is high. Leafminers are active and will cause damage that is similar to frost (below). Cut a leaf and hold it up and you may be able to see the dark spots of the larvae within the leaf.
Onions – Many direct seeded onions have reached the 3rd leaf stage and some are even a little further along. Onion maggots and cutworms are active.
Potatoes – Potatoes are planted and many fields are starting to emerge and fill in the row. Overwintering Colorado Potato Beetles are out and laying eggs. Keep an eye out for egg masses under leaves and hatching larvae to determine how your seed or in-furrow insecticide is holding up. Now is a good time to spot any emergence or seed-borne issues. We have seen rhizoctonia in some fields but also look out for Fusarium dry rot, soft rot and potential seed-borne late blight.
Rhubarb – Frost damaged rhubarb has recovered.
Sweet corn – Sweet corn is growing well
Tomatoes and Peppers – Transplants are coming along well, although some plants are suffering from heat stress and dry conditions. With storms coming through SW Ontario, transplants should be monitored for wind damage and potentially hail in some areas. Early season insect pressure has been low overall this season, but cutworm larvae have been active in other crops. For a refresher on what to be scouting for this time of year, check out this previous blog post on early season insect pests.
NOTE: Data as of June 10th, 2020
Pest Degree Day Forecasting
|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|
*- 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: