With June’s first week, many counties are experiencing a heavy lack of rain.
Garlic – Be on the lookout for leek moth damage as hardneck cultivars are scaped over the next two weeks (Figure 1). Refer to this article for managing leek moth: https://onvegetables.com/202305/17/leek-moth/. Snap scapes of hardneck cultivars as soon as possible to obtain the greatest yield benefit. Avoid using sickle bar mowers to remove scapes as they can easily spread garlic pathogens (including viruses) and often clip leaves during the scape removal process. Past research has shown that by accidentally removing one leaf when the scape was removed, bulb sizes were reduced by 13% and the yield was reduced by an average of 17.5%. The same trial showed that yield was greatly impacted as the number of leaves cut during mowing increased. If the top two leaves were cut, the yield was reduced by approximately 25%, almost outweighing any potential gains you would expect by removing the scape in the first place. Register for this years Garlic Growers field day on June 10th. Go to https://www.garlicgrowersofontario.com to register.
Brassica Crops – Transplants are starting to take off in fields that were planted in late April or early May. Cabbage maggot has reached its first-generation threshold in the majority of Southern Ontario. Dig up wilted transplants, even in dry areas, to inspect roots for maggots. Diamondback moth and imported cabbageworm continue to be the main insects causing wide-spread damage.
Onions – Some direct seeded fields are at the 4th leaf stage however most fields are averaging around the 1st leaf stage. Cutworm and maggot damage have been observed. Stake out 100 plants now to help determine how many onions make it to harvest. The heat from last week’s high temperatures may have caused heat canker in some fields.
Pest Degree Day Forecasting
|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|
*NOTE: Data as of June 7th, 2023
*- 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: