VCR – Vegetable Crop Report – June 8th, 2023

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.

**Figure 1**– Leek moth larvae found in a scape of a garlic plant (June 7, 2023)

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 4^th 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
Bruce***	443	388	241	160	82	287	388	132
Essex*	672	595	400	300	172	458	595	255
Chatham-Kent*	619	546	362	266	149	418	546	225
Norfolk**	593	521	346	251	136	398	521	209
Huron***	521	457	301	214	116	347	457	176
Wellington**	513	454	304	218	122	351	454	182
Simcoe County***	510	449	292	211	116	340	449	175
Durham***	551	486	316	229	124	366	486	191
Peterborough	511	449	283	195	96	333	449	159
Kemptville***	551	489	324	229	117	376	489	186
Sudbury***	445	394	262	187	104	304	394	154
Timiskaming***	430	380	242	167	92	286	380	137
Lambton**	568	500	324	235	127	378	500	195
Thunder Bay	337	292	177	123	61	213	292	99
Middlesex*	580	513	348	257	145	397	513	218
Renfrew	554	494	332	240	132	384	494	201