Tag Archives: fungal disease

Late blight alert – July 27th, 2017

This information is updated from an earlier article by Janice LeBoeuf.

We have had multiple reports of late blight in conventionally managed tomato fields this week.  Typically, this disease is well managed in tomatoes with a broadspectrum fungicide program including chlorothalonil.  However, high disease pressure due to environmental conditions, combined with a dense leaf canopy and rapid growth may have resulted in poor spray coverage and reduced efficacy.

Commercial growers should scout often and ensure they are using fungicides with good late blight activity in their fungicide program.  When late blight is in the area, spray intervals should be shortened.

Under continued high disease pressure, growers should consider adding a targeted late blight fungicide to the spray program.  If late blight has been identified in a field, use a fungicide with curative and antisporulent activity, see the table below for late blight fungicides and their properties. Continue reading Late blight alert – July 27th, 2017

Late blight alert – June 28

Late blight foliar lesionLate blight has been confirmed on tomatoes in Chatham-Kent.

Recent weather has been conducive to the development and spread of late blight.  Commercial growers should scout often and ensure they are using fungicides with good late blight activity in their fungicide program.  When late blight is in the area, spray intervals should be shortened. Continue reading Late blight alert – June 28

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

Ontario Fruit and Vegetable Convention presentations now available online

Ontario Fruit & Vegetable ConventionPresentation slides from the 2017 Ontario Fruit and Vegetable Convention (OFVC) are now posted online. Field vegetable content at this year’s OFVC included: Continue reading Ontario Fruit and Vegetable Convention presentations now available online

66th Annual Muck Vegetable Growers Conference

The 66th Annual Muck Vegetable Growers Conference will be held April 12-13 at the Bradford and District Memorial Community located at 125 Simcoe St., Bradford, ON. The conference is free and registration starts at 8:30. For more details please see:  http://www.uoguelph.ca/muckcrop/muckconference.html

Continue reading 66th Annual Muck Vegetable Growers Conference

Tomato fruit rots

There are many potential causes of fruit rot in tomato. In processing crops, we often see them when crop maturity is getting ahead of harvest.

Anthracnose

Anthracnose on tomatoThe most important fact to know about anthracnose fruit rot of tomato is that while symptoms appear only on ripe fruit, infections can be initiated on green fruit (you can’t see those infections). Fungicide programs must begin early enough to prevent the initial infection of green fruit. You can’t spray away an infection that’s already happened.

Black mold (alternaria)

Black mold (alternaria) on tomato fruitOverripe tomato fruit may develop black mold caused by Alternaria alternata. Symptoms can range from small, dark blotches to large sunken areas Lesions may develop soft, black fungal growth in warm, humid weather. Black fungal growth may also develop on existing wounds or lesions. Continue reading Tomato fruit rots