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VCR: Vegetable Crop Report – August 2, 2018

OntarioGDDMap August1

Temperature – All regions have accumulated more degree days than the 10-year average. A hot first half of July kept the current degree day accumulation on trend with the average and increased the gap in some areas.

Rainfall –  Rainfall has been the talk as of late. After a dry first half to July, many regions received some minor relief in the second half of the month. Some major downpours put some regions at or above their 10-year average. Some regions remain dry and below average including some parts of Essex, Bruce/Huron and Eastern Ontario. Spotty rainfall appears the be the norm.

Crop Updates

Brassica Crops –Tarnished plant bugs, flea beetles and Swede midge populations are high in many areas. Wilt symptoms are being seen in fields with high cabbage maggot pressure and clubroot. 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, cabbage loopers, cabbageworm, aphids and thrips.

Carrots – Leafhopper counts have been fairly high so far. Aster yellows is starting to show up in some fields but in low amounts at this point. Leaf blight has also started to show up. Many fields have canopies closing so if growers want to get a white mold fungicide on with decent coverage near the base of the plant, now might be a good time.

Celery –Tarnished plant bugs and Aster leafhoppers are active and have been found in low to moderate levels. Blackheart and celery leaf curl has been identified in multiple areas.

Garlic – The hot weather in early July caused many growers in SW Ontario to harvest early. Many growers in the Southern portion of the province have finished harvesting while those growing in Central and Eastern Ontario are starting. This year leek moth was detected for the first time in Lambton, Chatham-Kent and Huron counties. Many fields had pre-mature tip yellowing and dieback this year which may be due to Stemphylium leaf blight – similar to what is seen in onions. While grading after harvesting, sell bulbs with a damaged basal plate for table stock and only keep bulbs with healthy, white roots for seed stock. We are offering a second Garlic Workshop on September 5th from 9:30-3:30 that will cover all aspects of production and pest management of growing garlic in Ontario. Space is limited so please register early to avoid disappointment. Register by calling OMAFRA’s Agricultural Information Contact Centre at 1-877-424-1300.

Onion – A sporulation and infection period for downy mildew was reached in several onion growing regions over the last two weeks but there has been very few positive samples. Downy mildew of onions prefers cool temperatures below 22°C and wet conditions resulting in high relative humidity. Earliest direct seeded onions have reached the ten leaf stage while the majority of fields are in the eighth leaf stage. Onion maggot flies have reached their second generation in most regions and population levels are elevated. Many fields have had four insecticide applications to manage onion thrips as populations have been high in the hot weather during the first two weeks of July. Stemphylium leaf blight has been detected in most areas. Continue to scout for onion smut, purple blotch, botrytis, pink root and white rot.

Potatoes – Black cutworm tuber damage has been identified in Simcoe County last week. Look for small shotgun holes in the leaves and stems cut off near the ground. If you dig around the soil near damaged plants you can often find the larvae curled up as they only feed at night. Check out the OMAFRA factsheet on black cutworm at this link: CropIPM – Black Cutworm.
No late blight spores have been caught on the spore traps yet. Some Colorado potato beetle activity has been seen in some fields as 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 an insecticide in a different group such as a Group 3, 5, 6, 15 or 28 insecticide.

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

EssexDD August1EssexTP August1

EssexJP 5

LocationOnion MaggotSeedcorn MaggotCabbage MaggotLeek MothCarrot WeevilCarrot Rust FlyAster LeafhopperEuropean Corn Borer
For reference on the various thresholds, see table at the very bottom of this post.
Essex1556155613411239123916701042947

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Chatham-Kent County

Chatham-KentDD August1Chatham-KentTP August1

Chatham-Kent JP 3.png

LocationOnion MaggotSeedcorn MaggotCabbage MaggotLeek MothCarrot WeevilCarrot Rust FlyAster LeafhopperEuropean Corn Borer
For reference on the various thresholds, see table at the very bottom of this post.
Chatham-Kent159015901269115111711590977883

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Norfolk County

NorfolkDD August1NorfolkTP August1

Norfolk JP 2

LocationOnion MaggotSeedcorn MaggotCabbage MaggotLeek MothCarrot WeevilCarrot Rust FlyAster LeafhopperEuropean Corn Borer
For reference on the various thresholds, see table at the very bottom of this post.
Norfolk145314531246112211451561950856

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Huron County

HuronDD August1HuronTP August1

Huron JP 2

LocationOnion MaggotSeedcorn MaggotCabbage MaggotLeek MothCarrot WeevilCarrot Rust FlyAster LeafhopperEuropean Corn Borer
For reference on the various thresholds, see table at the very bottom of this post.
Huron13061306110599510091410819729

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Wellington County

WellingtonDD August1WellingtonTP August1

Wellington JP 2

LocationOnion MaggotSeedcorn MaggotCabbage MaggotLeek MothCarrot WeevilCarrot Rust FlyAster LeafhopperEuropean Corn Borer
For reference on the various thresholds, see table at the very bottom of this post.
Wellington13051305110399110051410816723

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Simcoe County

SimcoeDD August1SimcoeTP August1

Simcoe JP 2

LocationOnion MaggotSeedcorn MaggotCabbage MaggotLeek MothCarrot WeevilCarrot Rust FlyAster LeafhopperEuropean Corn Borer
For reference on the various thresholds, see table at the very bottom of this post.
Simcoe13091309110945610121410825734

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Durham County

DurhamDD August1DurhamTP August1

Durham JP 2

LocationOnion MaggotSeedcorn MaggotCabbage MaggotLeek MothCarrot WeevilCarrot Rust FlyAster LeafhopperEuropean Corn Borer
For reference on the various thresholds, see table at the very bottom of this post.
Durham13991399119554210971504907816

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Peterborough

PeterboroughDD August1PeterboroughTP August1

Peterborough JP 2

LocationOnion MaggotSeedcorn MaggotCabbage MaggotLeek MothCarrot WeevilCarrot Rust FlyAster LeafhopperEuropean Corn Borer
For reference on the various thresholds, see table at the very bottom of this post.
Peterborough13061306110244410031409814724

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Kemptville

KemptvilleDD August1KemptvilleTP August1

Kemptville JP 2

LocationOnion MaggotSeedcorn MaggotCabbage MaggotLeek MothCarrot WeevilCarrot Rust FlyAster LeafhopperEuropean Corn Borer
For reference on the various thresholds, see table at the very bottom of this post.
Kemptville13781378117252110721486876783

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Sudbury

SudburyDD August1SudburyTP August1

Sudbury JP 2

LocationOnion MaggotSeedcorn MaggotCabbage MaggotLeek MothCarrot WeevilCarrot Rust FlyAster LeafhopperEuropean Corn Borer
For reference on the various thresholds, see table at the very bottom of this post.
Sudbury1212121210204309281310751668

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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

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