on July 8 | in Ag News | by Jodie Deprez | with No Comments

From ONvegetables

Temperature – After a cool April, growing degree days have caught up to the 10-year average and surpassed the average in most areas towards the latter part of May. That trend has continued with this recent hot weather in many areas.

Rainfall –  After a wet April and a variable May, June has been dry. At just over halfway through the month of June, all regions across the province have accumulated below the average for this time. Many regions have accumulated less than 10mm of rain so far in June.

 

Crop Updates

Brassica Crops – Tarnished plant bugs are active. Flea beetles are in high numbers in some areas and will be more active at higher temperatures. Continue to scout for diamondback moth, cabbageworm, aphids and thrips. The first generation of cabbage maggot has emerged in most areas of Southwestern Ontario.

Carrots – Carrot weevil activity is winding down but the risk is still high in some fields. Carrot rust fly has reached the degree day threshold for emergence in the SW part of the province. Aster leafhoppers have been observed on sticky traps but numbers are low in most fields.

Celery – Scout for tarnished plant bugs as they are emerging and are typical found first around field borders.

Garlic – Many areas have seen scape emergence in the last week. Scout for slim, light-green 6-14mm leek moth larvae and look for damage on the newest leaves. Yellowing of foliage and tip dieback of older leaves is likely due to stress from herbicide damage, nutrient deficiency or dry conditions. Use a shovel to dig wilted plants and look for seedcorn maggot larvae, wireworms or rot in the basal plate. Rot in the basal plate may be due to bulb and stem nematode, white rot or Fusarium coming in as a secondary pathogen. Healthy roots should be white with very little brown to dark brown.

Onion – Earliest direct seeded onions are at the forth leaf stage while the majority of fields are in the 2nd leaf stage. Onion maggot flies are present and low levels of thrips are being seen in transplant fields where there are 5-6 true leaves. Thrips are usually first detected along field borders. Pull the leaves apart and look down into the leaf base for 2mm-long grey adults or very small yellow nymphs ~1mm in length. Onion fields next to hay or overwintering rye are at a greater risk as thrips move once the hay or rye is cut. The spray threshold for onion thrips is one thrips per leaf of plant from an average of 50 plants.

Potatoes – Late blight has been confirmed on tomatoes in New York State this past week. Even with this stretch of hot and dry weather, growers should be diligent in scouting for any signs of the disease. Remove any cull piles or volunteers on your farm. Many growers have been busy irrigating during this stretch of warm weather and lack of rainfall. Fields are flowering in the South Western regions of the Province and the crop is starting to size up nicely.

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
For reference on the various thresholds, see table at the very bottom of this post.
Essex	676	676	557	504	503	742	402	355

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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
For reference on the various thresholds, see table at the very bottom of this post.
Chatham-Kent	642	642	529	459	479	706	381	334

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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
For reference on the various thresholds, see table at the very bottom of this post.
Norfolk	593	593	488	415	438	650	345	302

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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
For reference on the various thresholds, see table at the very bottom of this post.
Wellington	548	548	442	377	392	604	299	254

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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
For reference on the various thresholds, see table at the very bottom of this post.
Huron	541	541	436	374	388	597	294	252

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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
For reference on the various thresholds, see table at the very bottom of this post.
Simcoe	533	533	429	112	380	586	289	246

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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
For reference on the various thresholds, see table at the very bottom of this post.
Durham	527	527	424	120	375	583	285	244

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Peterborough

Location	Onion Maggot	Seedcorn Maggot	Cabbage Maggot	Leek Moth	Carrot Weevil	Carrot Rust Fly	Aster Leafhopper	European Corn Borer
For reference on the various thresholds, see table at the very bottom of this post.
Peterborough	537	537	429	107	379	592	286	243

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Kemptville

Location	Onion Maggot	Seedcorn Maggot	Cabbage Maggot	Leek Moth	Carrot Weevil	Carrot Rust Fly	Aster Leafhopper	European Corn Borer
For reference on the various thresholds, see table at the very bottom of this post.
Kemptville	531	531	423	115	372	589	274	230

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Sudbury

Location	Onion Maggot	Seedcorn Maggot	Cabbage Maggot	Leek Moth	Carrot Weevil	Carrot Rust Fly	Aster Leafhopper	European Corn Borer
For reference on the various thresholds, see table at the very bottom of this post.
Sudbury	441	441	346	91	301	492	221	186

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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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