VCR – Vegetable Crop Report – June 29th, 2023

Welcome to this weeks installment of the Vegetable Crop Report! As June comes to a close, we have seen a major increase in rain over the past week. Many counties have come much closer to their Ten Year Average, while others have overcome it!

Brassica Crops – Harvest continues for broccoli, cabbage, cauliflower and kale. Higher amounts of rainfall the past week will mean that conditions are more favourable for Alternaria. Reference the Ontario Crop Protection Hub to determine what products are registered for Alternaria depending on the specific Brassica crop that you are growing. Early detection and management of Alternaria will reduce potential inoculum later in the season. Alternaria resistance has been documented in other regions outside of Ontario and it is important to rotate FRAC groups after every Alternaria application. Dig stunted plants and observe roots for cabbage maggot larvae or pupae (Figure 1). Continue to scout for diamondback moth and imported cabbageworm eggs and larvae.

**Figure 1** – Cabbage maggot pupae in stunted cauliflower transplant June 2023.

Garlic – Many areas have finished scaping and many fields are showing leaf tips starting to senesce. Tip dieback is likely due to stress which could be from late spring frosts, infrequent soil moisture, or root dieback caused by a pest or pathogen. Most fields with tip dieback were fairly dry in May despite the amount of precipitation we had in most areas in April. Continue to scout for leek moth damage. The frass and chewed pieces of leaf can look like sawdust on the leaves of garlic. The number of leek moth adults found in traps have increased over the past week and the second major flight will be over the next 3 weeks depending on the area. Dig up plants showing yellowing of the leaves from the bottom upwards and inspect the bulb and basal plate. Yellowing of the lower leaves is generally associated with stem and bulb nematode but it could also be Botrytis neck rot (Figures 2-3).

**Figure 2** – Botrytis neck rot causing wilted, green leaves turning yellow from the bottom of the plant upwards.

**Figure 3** – Black sclerotia of Botrytis neck rot are often observed on the bulb with greyish-green spores visible on the stem of the plant just above the crown.

Peppers – Growers should be aware that in univoltine areas that peak flight of European corn borer (ECB) has begun. In overlap and bivoltine areas, peak flight of the first generation of ECB is also ongoing. Growers can use scouting and pheromone traps to help determine the presence of ECB in their crop, as there a very few pepper fruits currently on plants.

Tomatoes – Transplants are looking great and early plantings are starting to set fruit. With the recent storms, there is always a risk of disease coming in from the south and growers should be scouting for early symptoms of bacterial diseases. Grower should also be on the look out for symptoms of soil borne disease like fusarium, as the soils are moist. If you see unusual plant symptoms, like wilting, yellowing leaves, etc. and are concerns about fusarium, please reach out to Amanda Tracey at amanda.tracey@ontario.ca.

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***	729	653	443	320	179	510	653	271
Essex*	1004	906	648	506	315	727	906	440
Chatham-Kent*	928	834	588	450	269	665	834	387
Norfolk**	913	820	581	444	267	655	820	381
Huron***	804	719	500	371	211	568	719	312
Wellington**	808	728	515	388	229	584	728	331
Simcoe County***	805	724	503	380	223	572	724	324
Durham***	876	789	557	428	259	627	789	368
Peterborough	798	716	489	362	203	560	716	306
Kemptville***	875	792	564	427	252	637	792	363
Sudbury***	739	668	472	356	213	535	668	303
Timiskaming***	719	648	447	331	195	512	648	280
Lambton**	875	785	543	410	236	619	785	347
Thunder Bay	604	539	360	264	142	417	539	220
Middlesex*	904	816	584	449	272	656	816	388
Renfrew	869	789	567	434	267	639	789	375