VCR – Vegetable Crop Report – June 1st, 2023

Most counties fell behind their monthly totals for precipitation compared to their ten year average while the majority of counties came close to their ten year average when it comes to degree days with a base of 5°C for the month of May.

Brassica Crops – The hot and dry weather has led to poor transplant establishment in fields without adequate moisture present. The threshold for the first generation of cabbage maggot has yet to be reached but will likely be active by next week in southern parts of the province. Damage from cutworms and flea beetles is widespread this year and many fields have already found diamondback moths and imported cabbageworms.

Garlic – Scapes are just starting emerge, and the majority should be visible in the next two weeks on hardneck cultivars. Tipburn on older leaves is widespread across the province this year and may be due to frost damage, lack of moisture over the past month or herbicide injury. It is difficult to find plants that are still green to the tip. Irrigation may be required for bulbs to size well in areas that have had little precipitation over the past month. Register for this years Garlic Growers field day on June 10th. Go to https://www.garlicgrowersofontario.com to register.

Onion – Direct seeded fields are between the flag and 2 leaf stage. Transplants are doing well given they have had enough moisture to establish. Onion maggot flies are active in most regions; be on the lookout for wilted plants. Stake/count 50 or 100 plants now and count later in the seasons to determine how many onions make it to harvest. Cutworm damage has been observed in multiple fields (Figure 1). Dig around suspect plants that look like they have been cut with scissors to look for cutworm larvae within the top inch of the soil surface. Control volunteer onions in neighbouring fields as this can be a source for fungi inoculum like Stemphylium or pests like onion thrips.

**Figure 1:** Black cutworm damage to a direct seeded onion.

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***	351	302	177	110	53	216	302	88
Essex*	560	490	317	230	123	367	490	192
Chatham-Kent*	515	449	286	204	108	335	449	170
Norfolk**	486	421	267	186	92	312	421	150
Huron***	424	367	232	159	80	271	367	128
Wellington**	414	362	232	161	85	272	362	132
Simcoe County***	414	360	224	157	83	264	360	128
Durham***	444	385	237	163	79	279	385	132
Peterborough	420	365	219	146	67	263	365	117
Kemptville***	456	401	257	176	86	302	401	140
Sudbury***	322	279	171	112	53	205	279	87
Timiskaming***	328	285	168	107	53	205	285	84
Lambton**	483	420	262	185	95	310	420	151
Thunder Bay	240	203	108	68	27	137	203	52
Middlesex*	477	417	269	190	97	313	417	157
Renfrew	435	382	241	163	76	286	382	131

*NOTE: Data as of May 31st, 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.

European Corn Borer Update – May 28^th, 2023

Essex & Chatham-Kent Areas (2-generation/bivoltine area): As of Sunday, May 28, DD accumulations were approximately 159 in Harrow, 175 in Windsor, and 138 in Ridgetown. ECB flight of the 1^st generation has begun in Harrow and Windsor, and will likely begin within a week in Ridgetown, depending on temperatures. Populations will continue to increase until peak flight. Start planning for ECB monitoring by getting your black light traps or pheromone traps ready and training your scouts for signs of larval entry holes in the peppers.

London & Sarnia Areas (overlap area): As of May 28, the DD accumulations were approximately 138 in London, and 124 in Sarnia. For the 2-generation population, first flight of the 1^st generation will likely begin within the next week or two in these areas, depending on temperatures. Populations will continue to increase until peak flight. Start planning for ECB monitoring by getting your black light traps ready and training your scouts for signs of larval entry holes in the peppers. First flight of the 1-generation population is likely a few weeks away.

Vineland Area (1-generation/univoltine area): As of May 28, the DD accumulations were approximately 119. First flight is likely a few weeks away. Start planning for ECB monitoring by getting your black light traps ready and training your scouts for signs of larval entry holes in the peppers or pinhole/window pane feeding in sweet corn.