Category Archives: Carrot

Alliums, Carrot, Events, Leafy Vegetables, Pest Management, Research

Muck Crops Research Station Grower Field Day

August 24, 2017 Dennis Van Dyk Leave a comment

If you are a carrot or onion grower, or just interested in the latest vegetable research you are invited to the University of Guelph Muck Crops Grower Field Day on Thursday, September 7. See the announcement below:

Grower Field Day Variety Trials 2017 invitation

The carrot and onion variety trials will be on display with entries from the major vegetable seed suppliers.

You can also view the onion research trials on topics like Stemphylium leaf blight, downy mildew and onion maggot. Research trials on carrot weevil control, carrot weed control and celery leaf curl will be featured and it’s also great opportunity to interact with University of Guelph researchers, other growers and industry reps.

The Muck Crops Research Station is at 1125 Woodchoppers Lane, King ON, L7B 0E9 with Stokes Seeds providing coffee and donuts and a free lunch compliments of Solar Seeds.

Alliums, Brassica Vegetables, Carrot, Disease, garlic, Insects, Leafy Vegetables, Onions, Potato, Vegetables

Disease and Insect Update – July 13, 2017

July 13, 2017 Dennis Van Dyk Leave a comment

Insect Degree Days

Weather Station Location	Onion Maggot	Seedcorn Maggot	Cabbage Maggot	Carrot Weevil	Carrot Rust Fly	Aster Leafhopper
Weather Station Location	(base 4°C)	(base 4°C)	(base 6°C)	(base 7°C)	(base 3°C)	(base 9°C)
Harrow	1265	1265	1044	938	1380	746
Ridgetown	1153	1153	937	838	1268	660
Delhi	1125	1125	910	813	1237	636
Goderich	973	973	775	684	1076	533
Guelph	928	928	735	646	1034	492
Bradford*	987	987	795	708	1086	547
Kemptville	969	969	786	700	1069	544
Sudbury	754	754	597	525	845	394

*Bradford weather, degree day data and information courtesy of the University of Guelph – Muck Crops Research Station

Summary

Cabbage, onion and seedcorn maggot fly activity should be beginning to increase from Norfolk across to Lambton and south. Most of the province is in-between generations currently but should start seeing the next generation emerge in the next few weeks depending on weather.

For carrot weevil we are now well past the degree day threshold for 90% oviposition across the province. This year we will be monitoring for the presence of a possible 2nd generation of carrot weevils. If you think you are having late season carrot weevil issues, please contact Dennis (dennis.vandyk@ontario.ca).

We have reached the DD threshold for carrot rust fly in Harrow only. The rest of the province should be between generations currently.

Aster leafhoppers adults are now present across the province.

Disease Forecasting

Onion Downy Mildew (DOWNCAST disease forecasting model):
In Bradford, conditions have not been conducive to sporulation so risk of downy mildew is low to moderate.
In Lambton county, sporulation infection periods (SIP) have been accumulated from July 2-5 and then again on July 12 meaning conditions and risk is high in transplant onions and moderate to high in seeded onions.

Late Blight:
Late blight DSVs are accumulating quickly in most areas of the province.
Late blight on potatoes has been confirmed in the Simcoe/Durham county region but the risk remains high across the province. Growers should be applying late blight specific fungicides along with a broad-spectrum fungicide like chlorothalonil (Bravo, Echo), metiram (Polyram) or mancozeb (Manzate, Penncozeb, Dithane).

Check OnPotatoes for up to date late blight risk information and USAblight for currently reported late blight incidence in the Great Lakes region.

Crop Updates

Onions: Earliest direct seeded onions have six true leaves while the majority are at the four to five leaf stage. Stemphylium leaf blight, purple blotch, onion smut and Botrytis leaf blight has been detected in Ontario. See the Stemphylium leaf blight article in a previous OnVegetables post for more information.

Garlic: Leaf dieback has been seen in multiple areas with Fusarium basal rot and bulb and stem nematode. Carefully inspect the basal plate and look for fungal growth or rot on the stem. For confirmation, send suspect cloves to a certified pest diagnostic clinic for bulb and stem nematode extraction. Leek moth has been identified in pockets of Southwestern Ontario.

Brassica: Cabbage maggot is active and severely infested plants may wilt in hot weather. Wilt can also be caused by clubroot, a soil-borne pathogen infecting the roots and causing club-like symptoms. A clubroot survey is underway; please contact travis.cranmer@ontario.ca for more information if you find clubroot in your field. Swede midge has also been reported throughout Southwestern Ontario and is affecting the meristems later seeding dates of multiple brassica crops. Continue to scout for flea beetles, diamondback moth, cabbageworm, aphids, thrips and tarnished plant bugs.

Celery: Tarnished plant bugs have been detected in Thedford and the Holland Marsh. Scout for damage from carrot weevils laying eggs.

Below are the various insect DD thresholds for reference.

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

Carrot Weevil	138 – 156	Egg laying (oviposition) begins
Carrot Weevil	455	90% of the egg-laying (oviposition) is complete
Aster Leafhopper	128	Overwintering eggs hatch
Aster Leafhopper	390	Local adult emergence

Alliums, Carrot, Insects, Onions, Vegetables

Insect Pest and Crop Degree Day Update – June 13, 2017

June 13, 2017 Dennis Van Dyk Leave a comment

Insect Degree Days

Weather Station Location	Onion Maggot	Seedcorn Maggot	Cabbage Maggot	Carrot Weevil	Carrot Rust Fly	Aster Leafhopper
Weather Station Location	(base 4°C)	(base 4°C)	(base 6°C)	(base 7°C)	(base 3°C)	(base 9°C)
Harrow	716	716	556	481	800	351
Ridgetown	629	629	474	407	712	290
Delhi	618	618	464	399	700	284
Goderich	500	500	365	305	573	215
Guelph	463	463	332	274	538	182
Bradford*	523	523	388	329	593	227
Kemptville	502	502	381	326	571	232
Sudbury	353	353	257	216	412	147

*Bradford weather, degree day data and information courtesy of the University of Guelph – Muck Crops Research Station

Summary

Onion maggot flies are active in most areas of the province.

Cabbage maggot has reached the DD threshold for emergence in all areas of the province except up North.

The 2nd generation of seedcorn maggot flies have reached the DD threshold for emergence in Harrow. In most other areas of the province, we are just getting over the 1st generation or are currently between generations.

Carrot weevil adults are currently laying eggs, if they are present. In Harrow we have past the degree day threshold for 90% oviposition. This means if carrot weevils are present then almost all of the egg-laying has been completed.

The 1st generation of carrot rust fly is emerging or has emerged in the province.

All areas of the province have reached the DD threshold for overwintering Aster Leafhopper eggs to hatch. Harrow is nearing adult emergence of the local population of Aster Leafhopper adults.

IPM Update

Onion: Earliest direct seeded onions are at the fifth leaf stage while the majority are the third leaf stage. There is a low risk for Botrytis leaf blight. When scouting, check the underside of the outer leaves and look for small, light green to yellow lesions surrounded by white halos. Herbicide injury will be often more white than green but can be mistaken for Botrytis leaf blight. Thrips have been detected in most onion growing areas; 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.

Garlic: Continue to scout for symptoms of rot in the basal plate which may be due to bulb and stem nematode, Fusarium basal rot or white rot. Look for plants that have yellowing of foliage or tip dieback and dig carefully around the plant and look for fungal growth or rot on the stem. Onion thrips and onion maggot flies have been detected.

Brassica: First generation of cabbage maggots are active. Continue to scout for diamondback moth, cabbageworm, aphids, thrips and tarnished plant bugs.

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

Below are the various insect DD thresholds for reference.

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

Carrot Weevil	138 – 156	Egg laying (oviposition) begins
Carrot Weevil	455	90% of the egg-laying (oviposition) is complete
Aster Leafhopper	128	Overwintering eggs hatch
Aster Leafhopper	390	Local adult emergence

Alliums, Carrot, Insects, Onions, Vegetables

Insect Pest and Crop Degree Day Update – June 5, 2017

June 5, 2017 Dennis Van Dyk Leave a comment

Insect Degree Days

Weather Station Location	Onion Maggot	Seedcorn Maggot	Cabbage Maggot	Carrot Weevil	Carrot Rust Fly	Aster Leafhopper
Weather Station Location	(base 4°C)	(base 4°C)	(base 6°C)	(base 7°C)	(base 3°C)	(base 9°C)
Harrow	613	613	467	400	690	283
Ridgetown	534	534	394	333	611	231
Delhi	519	519	380	321	593	220
Goderich	414	414	292	239	479	164
Guelph	396	396	278	227	463	149
Bradford*	438	438	318	266	501	178
Kemptville	409	409	302	254	471	175
Sudbury	261	261	179	146	314	91

Summary and IPM Update

Onion thrips have been seen on transplants in the Grand Bend area but at this point numbers are low.

Onion maggot flies have emerged and are active in most areas of the province. Current trap counts are low in the Holland Marsh area* and low to moderate in the Grand Bend area.

Cabbage maggot has reached the DD threshold for emergence in Harrow, Ridgetown, Delhi and Bradford. It is nearing the DD threshold in Goderich, Guelph and Kemptville.

Carrot weevil adults are currently laying eggs, if they are present.

The 1st generation of carrot rust fly has begun to emerge in almost all areas of the province.

Most of the province (Ridgetown, Delhi, Goderich, Guelph, Bradford, Kemptville) have reached the DD threshold for overwintering Aster leafhopper eggs to hatch. Harrow is nearing adult emergence of the local population of Aster Leafhopper adults. Continue reading Insect Pest and Crop Degree Day Update – June 5, 2017 →

Alliums, Brassica Vegetables, Carrot, Insects, Onions, Vegetables

Insect Pest and Crop Degree Day Update – May 26

May 26, 2017 Dennis Van Dyk Leave a comment

Insect Degree Days

Weather Station Location	Onion Maggot	Seedcorn Maggot	Cabbage Maggot	Carrot Weevil	Carrot Rust Fly	Aster Leafhopper
Weather Station Location	(base 4°C)	(base 4°C)	(base 6°C)	(base 7°C)	(base 3°C)	(base 9°C)
Harrow	468	468	342	285	535	189
Ridgetown	408	408	288	237	475	155
Delhi	391	391	271	222	455	141
Goderich	308	308	206	164	363	108
Guelph	284	284	186	145	342	87
Bradford*	318	318	205	172	369	112
Kemptville	304	304	217	179	356	119
Sudbury	168	168	105	82	210	47

Continue reading Insect Pest and Crop Degree Day Update – May 26 →

Carrot, Crop Protection, Insecticides, Insects, Pest Management, Resistance, Vegetables

Carrot Weevil Control Update

April 25, 2017 Dennis Van Dyk Leave a comment

Carrot weevil remains the most important insect pest to many Ontario carrot growers, and the amount of damage seems to be increasing in recent years. Carrot weevil females overwinter in the soil and plant debris and lay their eggs in cavities in the crown of the carrots. These eggs develop and hatch into larvae and begin to feed on the carrot root. Feeding damage from the carrot weevil larvae causes unmarketable tunneling near the crown of the carrot and can account for significant losses to commercial growers.