VCR – Vegetable Crop Report – June 27, 2019

Temperature – The cool wet spring has continued into the summer in all growing regions of Ontario with all counties marginally, to significantly behind their 10-year average degree day accumulations. While some regions are now receiving near average temperatures, late planting dates has slowed the growth and development of many crops in most planted areas compared to normal.

Rainfall – Rainfall has generally slowed in most regions again this week and planting in most regions is now near completion, or completed already. Kemptville and Norfolk county have exceeded their 10-year precipitation averages, while Chatham and Sudbury are quickly approaching their respective averages for June. The remaining growing regions range from significantly below, to marginally below their 10-year average rainfall totals for June.

Crop Updates

Brassica Crops – Crop conditions have been favourable for Alternaria in some areas. Depending on the Brassica, not all fungicides are labelled for use; see Table 1 below for fungicides registered on different crop groups. Diamondback moths, imported cabbageworms, tarnished plant bugs and aphids are active. Cabbage maggot and flea beetle levels are high in several areas. Table 1, Fungicides registered for use on various brassica vegetables

Carrot – Carrot weevil activity should be winding down in the Southern part of the province.

Celery – Carrot weevils are active. On celery, carrot weevils leave scratch marks along the stalk that turn a yellow/orange colour as the wounds heal. The degree day threshold for aster leafhoppers and tarnished plant bugs has been reached in all growing regions.

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 infrequent soil moisture, lack of or surplus of nutrients or root dieback. Continue to scout for leek moth by looking for damaged leaves and stems. The frass and chewed pieces of leaf looks can look like sawdust on the leaves. Leek moths have been found in low numbers this past week but we are likely close to the second peak flight.

Onions – Direct seeded onions are at the 3rd to 6th leaf stage and transplants are up to 8 leaves in some areas. Stemphylium leaf blight has been detected in transplants and direct seeded onions and given the weather, keep scouting for Botrytis and downy mildew. Cutworm damage has been high in some fields and the level of thrips has been low thus far into the season. The second peak of onion maggot will be starting in many areas over the next couple of weeks.

Potatoes – We’ve seen potato leafhopper numbers jump in some fields. Be on the lookout for leafhoppers and symptoms of hopperburn (seen in the picture below). Overwintering Colorado Potato Beetle adults are active and laying eggs. Eggs are hatching and small larvae are being found in some fields. If you used a neonic at seeding, make sure you are using a different mode of action for any follow-up applications. If you are not seeing the control you usually do, please contact Dennis (519-766-5337) for free resistance testing.

Severe hopperburn

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
Essex*	950	855	600	456	280	681	855	389
Chatham-Kent*	839	747	504	366	191	580	747	306
Norfolk**	815	727	493	360	186	567	727	303
Huron***	642	563	355	241	102	418	563	192
Wellington**	657	579	371	259	120	434	579	213
Simcoe County***	636	557	352	242	108	414	557	197
Durham***	678	599	394	286	142	456	599	238
Peterborough	661	582	372	254	112	437	582	206
Kemptville***	722	642	432	311	151	498	642	254
Sudbury***	509	444	279	192	83	328	444	156