Category Archives: Vegetables

2017 Growing Degree Days for European Corn Borer – June 19, 2017

The first generation of European corn borer adults are at peak flight in the Bivoltine area. In the overlap areas, the emergence of the univoltine strains is beginning as well as the peak flight of the first generation bivoltine strains.  Pest pressure in both areas is expected to increase over the next week.  In the univoltine areas, first catch of adult ECB moths can be expected within the next week.

Note: we are experimenting with this new format for communicating growing degree days for European corn borer. As we refine the techniques the quality of the charts below will improve. Thank you for your patience.

Scouting for onion thrips

Onion thrips (Thrips tabaci) feed on more than just onions; they also feed on cabbage, leaf lettuce, a variety of other vegetables and fruits, field crops, and many weed species. Thrips are unique from other insects as they have rasping-sucking mouthparts that allow them to scratch the cell walls of leaves, suck up the cell contents including the chlorophyll, and leave behind a shiny, translucent trail on the leaf. A single female can produce Continue reading Scouting for onion thrips

Cucurbit Downy Mildew Report for the Week of June 19th, 2017

Cheryl Trueman, University of Guelph – Ridgetown Campus

Scouting for downy mildew in pickling cucumber fields in Norfolk County began on June 13 and in Kent County on June 19.

You can track sightings of downy mildew in North America on the IPMpipe Cucurbit Downy Mildew website.

More information:
2017 Downy Mildew Control Strategy for Cucumber Crops

2016 Fungicide efficacy and fungicide program results

The downy mildew scouting program is sponsored by the Ontario Cucumber Research Committee. Field scouting in Norfolk County is managed by Tania Keirsebilck-Martin at the Norfolk Fruit Growers’
Association. Field scouting in Kent County is managed by Cheryl  Trueman at the Ridgetown Campus, University of Guelph. We thank Elaine Roddy, OMAFRA vegetable specialist, for her guidance with
implementing this program.

The benefits of removing garlic scapes

The wild ancestors of today’s garlic, Allium sativum, originated thousands of years ago in what is believed to be garlic’s center of origin, Uzbekistan and Turkmenistan. Garlic spread across the globe as it became a popular vegetable, spice, and medicinal plant. The varieties of cultivars we have today were each selected for Continue reading The benefits of removing garlic scapes

Downy Mildew Report for the week of June 12, 2017

By Cheryl Trueman, University of Guelph – Ridgetown Campus

Scouting for downy mildew in pickling cucumber fields in Norfolk County began on June 13 (3 of 5 sites) and will begin in Kent County on June 19.You can track sightings of downy mildew in North America on the IPMpipe Cucurbit Downy Mildew website.
More information:
2017 Downy Mildew Control Strategy for Cucumber Crops
2016 Fungicide efficacy and fungicide program results.

 

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

Insect Degree Days

Weather Station Location Onion Maggot Seedcorn Maggot Cabbage Maggot Carrot Weevil Carrot Rust Fly Aster Leafhopper
(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.

 

Ontario DD Map June 11 2017

 

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
455 90% of the egg-laying (oviposition) is complete
Aster Leafhopper 128 Overwintering eggs hatch
390 Local adult emergence

 

Making Lemonade Out of Lemons – A Tomato Fungicide Stewardship Tip Amidst Changing Regulations

Cheryl Trueman (Ridgetown Campus, University of Guelph) & Janice LeBoeuf (OMAFRA)

It seems like recently there have been a rash of proposed or pending pesticide regulation changes that affect field growers, and tomato growers are no exception. There are re-evaluations ongoing for a number of products used in tomatoes, including mancozeb, neonicotinoids, and Lannate, as well as Ethrel, but the big one that comes to mind for field tomato growers is the proposed changes to the use of chlorothalonil (Bravo, Echo). The final outcome of this review is not yet known, but it’s likely that significant changes to the chlorothalonil labels are coming.

Chlorothalonil is a go-to fungicide for tomato growers. Data from trials at Ridgetown Campus demonstrate its value. Chlorothalonil is often just as good at controlling early blight, Septoria leaf spot, and anthracnose fruit rot as alternative fungicides, and it also provides protection from late blight, which many targeted fungicides do not. It’s a good value active ingredient for tomato disease management and has a low risk of resistance development. But, if proposed changes go through, the number of chlorothalonil applications you can use will be drastically cut.

So, have you thought about how you are going to adapt? Continue reading Making Lemonade Out of Lemons – A Tomato Fungicide Stewardship Tip Amidst Changing Regulations