VCR: Vegetable Crop Report – July 9, 2018

Temperature – A hot June has pushed the accumulated degree days above the 10-year average across the province.

Rainfall –  Rainfall has been very spotty over the last month. In general, rainfall was below average for most areas of the province. Some areas had some significant rain events which pushed them over the long term average. The amount of rainfall received on June 18 basically determined whether the region is below or above the average with some stations receiving up to 70mm of rain that day.

Crop Updates

Brassica Crops – Swede midge is targeting head brassicas, cabbage loopers are laying eggs and cabbage maggot, aphids and thrips populations are high in some fields. Tarnished plant bugs are present and flea beetles will be more active at the higher temperatures we have seen over the past week. Wilt has been seen in some fields due to cabbage maggot damage and clubroot. Clubroot is caused by a soil-borne pathogen infecting the roots and causing club-like symptoms on Brassicas. Pull suspect plants and observe roots for large clubs. A clubroot survey to determine the clubroot pathotype / strain is underway; please contact travis.cranmer@ontario for more information if you find clubroot in your field. Continue to scout for diamondback moth, cabbageworm, aphids and thrips.

Carrots – Look for signs of heat canker in later seeded or re-seeded carrot fields. Young carrots are susceptible to being burnt off at the soil level. Aster leafhoppers have reached their degree day emergence threshold and are being caught on sticky cards. Some fields have recorded high levels. No symptoms of aster yellows have been observed yet. Carrot rust fly is approached the 2nd generation threshold in the SW tip of the province. 1st generation numbers were low. Carrot weevil is now well past the DD threshold for egg-laying. Activity should be low to none.

Celery – Scout for tarnished plant bugs as they are emerging and are typical found first around field borders. Aster leafhoppers have been found in low to moderate levels. Blackheart has been identified in some areas. Keep a look out for celery leaf curl.

Garlic – Leek moth has been detected in many counties of SW Ontario where it has never been detected before. We are now entering the second flight and moth counts have been high in pheromone traps. Larvae will be emerging from eggs within the next week and are most vulnerable to insecticides as they make their way to the meristem. Most fields are showing tip yellowing and dieback on most of the leaves. Plants with the bottom 3-5 leaves turning yellow are likely infested with bulb and stem nematode. Dig carefully around the plant to take as many roots as possible when sampling stunted or poor looking plants. Carefully inspect the basal plate and look for fungal growth or rot on the stem. Healthy roots should be white with very little brown to dark brown. Damage to the basal plate is usually caused by nematodes, seedcorn maggot larvae or wireworms.

Onion – Earliest direct seeded onions are at the seventh leaf stage while the majority of fields are in the fifth leaf stage. Onion maggot flies are present in low to moderate levels. Most fields have had two insecticide applications to manage thrips as levels are over the threshold. Stemphylium leaf blight has been detected in the Holland and Thedford marsh but in relatively low levels. Plants with herbicide damage seem to be the first to show signs of stemphylium. Damage from onion/seedcorn maggot, onion smut and pink root have been observed. Continue to scout for white rot, botrytis leaf blight and purple blotch.

Potatoes – Growers have been busy irrigating to keep the crop going in this heat. Colorado potato beetle larvae are active in some spots as some of the at-plant insecticides are wearing off. Some growers might need to spot or perimeter spray. If you applied a neonic at-planting never follow up with another Group 4 neonic. Rotate with a Group 5,6 or 28 insecticide. No late blight has been reported.

Select a region below for the latest weather, crop and pest degree day information:

Essex County
Chatham-Kent County
Norfolk County
Huron County
Wellington County
Simcoe County
Durham County
Peterborough
Kemptville
Sudbury

 

 

Essex County

Location	Onion Maggot	Seedcorn Maggot	Cabbage Maggot	Leek Moth	Carrot Weevil	Carrot Rust Fly	Aster Leafhopper	European Corn Borer
Essex	1106	1106	941	865	864	1195	717	647
For reference on the various thresholds, see table at the very bottom of this post.

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Chatham-Kent County

Location	Onion Maggot	Seedcorn Maggot	Cabbage Maggot	Leek Moth	Carrot Weevil	Carrot Rust Fly	Aster Leafhopper	European Corn Borer
Chatham-Kent	1066	1066	905	811	830	1153	684	614
For reference on the various thresholds, see table at the very bottom of this post.

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Norfolk County

Location	Onion Maggot	Seedcorn Maggot	Cabbage Maggot	Leek Moth	Carrot Weevil	Carrot Rust Fly	Aster Leafhopper	European Corn Borer
Norfolk	1046	1046	887	787	810	1130	663	593
For reference on the various thresholds, see table at the very bottom of this post.

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Huron County

Location	Onion Maggot	Seedcorn Maggot	Cabbage Maggot	Leek Moth	Carrot Weevil	Carrot Rust Fly	Aster Leafhopper	European Corn Borer
Huron	919	919	767	680	694	999	552	486
For reference on the various thresholds, see table at the very bottom of this post.

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Wellington County

Location	Onion Maggot	Seedcorn Maggot	Cabbage Maggot	Leek Moth	Carrot Weevil	Carrot Rust Fly	Aster Leafhopper	European Corn Borer
Wellington	925	925	772	683	697	1006	556	487
For reference on the various thresholds, see table at the very bottom of this post.

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Simcoe County

Location	Onion Maggot	Seedcorn Maggot	Cabbage Maggot	Leek Moth	Carrot Weevil	Carrot Rust Fly	Aster Leafhopper	European Corn Borer
Simcoe	915	915	763	278	690	992	551	484
For reference on the various thresholds, see table at the very bottom of this post.

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Durham County

Location	Onion Maggot	Seedcorn Maggot	Cabbage Maggot	Leek Moth	Carrot Weevil	Carrot Rust Fly	Aster Leafhopper	European Corn Borer
Durham	960	960	804	318	729	1041	588	521
For reference on the various thresholds, see table at the very bottom of this post.

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Peterborough

Location	Onion Maggot	Seedcorn Maggot	Cabbage Maggot	Leek Moth	Carrot Weevil	Carrot Rust Fly	Aster Leafhopper	European Corn Borer
Peterborough	909	909	753	263	679	988	538	471
For reference on the various thresholds, see table at the very bottom of this post.

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Kemptville

Location	Onion Maggot	Seedcorn Maggot	Cabbage Maggot	Leek Moth	Carrot Weevil	Carrot Rust Fly	Aster Leafhopper	European Corn Borer
Kemptville	939	939	781	299	706	1023	558	489
For reference on the various thresholds, see table at the very bottom of this post.

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Sudbury

Location	Onion Maggot	Seedcorn Maggot	Cabbage Maggot	Leek Moth	Carrot Weevil	Carrot Rust Fly	Aster Leafhopper	European Corn Borer
Sudbury	818	818	675	252	606	893	478	419
For reference on the various thresholds, see table at the very bottom of this post.

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Thresholds

Use these thresholds as a guide, always confirm insect activity with actual field scouting and trap counts.

Degree Days
	1st generation	2nd generation	3rd generation
Onion Maggot	210	1025	1772
Seedcorn Maggot	200	600	1000
Cabbage Maggot	314-398	847-960	1446-1604
Carrot Rust Fly	329 – 395	1399-1711	n/a
Leak Moth	445	Egg to adult development after two nights of >9°C
Carrot Weevil	138 – 156	Egg laying (oviposition) begins
	455	90% of the egg-laying (oviposition) is complete
Aster Leafhopper	128	Overwintering eggs hatch
	390	Local adult emergence