Large gardens require careful chemical choices

Consultant offers courses | A lack of government information on the latest pesticide registration changes can be problematic

More than 200 black-clad people in the audience nodded when horticulturist Paul Ragan mentioned the problem of portulaca in vegetable gardens.


The troublesome weed, also known as purslane, is a problem in many gardens, and those at a March 20 Hutterite-oriented workshop in Lethbridge about growing vegetables and small fruits were well acquainted with weed control challenges.


Ragan knew that, just as he knows his way around vegetable gardening. He spent 31 years with Alberta Agriculture in Brooks and now works as a consultant for Hutterite colonies and commercial vegetable and fruit operations.


He has compiled a manual outlining solutions to weed, insect and disease problems in large gardens. An overview of the manual was the focus of the workshop, the third one organized by area colonies.


David Mandel of Kings Lake Colony near Foremost, Alta., said the meetings have been well received by Hutterian brethren, most of whom grow and maintain large vegetable gardens for their own use and for sale at farmers markets and retailers.


Ragan said constant updates on chemical registrations and safety requirements are vital when growing vegetables on a larger scale.


“One of the biggest problems I find is keeping the producer updated on what is actually registered for the various pest issues that they’re facing,” he said in an interview during a workshop break.


“We don’t have any provincial government publications that keep the growers updated, and that’s why I do that annually. From a food safety point of view, it’s so important to make sure they’re using products that do have registration and when they use a product, they use it at the label rate and also abide by the pre-harvest interval.”


Ragan said he expects control of late blight in potatoes and tomatoes to be a major problem again this year. Regular use of fungicides will be needed to keep it in check.


Pea leaf weevil in fresh market peas and root maggot in other crops are also likely challenges this spring and summer.


He said those pests can be handled, but he worries about new problems that might be inadvertently introduced.


“With garlic last year, we had fusarium bulb rot. It was a very serious problem last year. People bringing in product from outside the province to plant here, like garlic bulbs, and importing diseases and insects that we don’t have here, they’re bringing them in from other jurisdictions.”


For example, jumbo onions are produced only from transplants, many of which come from Arizona and California, where a disease called white rot is a problem. Ragan said white rot is not in Canada, but it could arrive with the transplants.


“I’m always worried that we’re going to introduce something here that’s going to cause us a chronic problem.”


Much of Ragan’s presentation centred on chemical controls, but Mandel said most colonies strive to limit pesticide use on their vegetable crops.


“We eat all this food too,” he said. 


“Not to imply that we feel the public is any less important than we are, but yes, we grow what we eat but at the same time we want to make sure that the consumers of our food are kept safe as well.”


Kings Lake Colony plants six acres of garden, half of it in carrots. Mandel said he considers six acres to be the average size of most Hutterite gardens.


Tillage and hand pulling are the primary methods of weed control. Insecticides and fungicides are also required on some crops. 


Mandel said it would be irresponsible not to treat late blight in potatoes and tomatoes, given its ease of spread and potential for widespread damage to other growers’ crops.


As for the portulaca problem, Ragan provided a list of registered herbicides for use in specific crops. Growers should check labels for appropriate application times and conditions:


  • cucumbers, pumpkins some squash: Alanap 3 

  • snap beans, sweet corn, peas: Basagran + Assist

  • cole crops, garlic, peppers, pumpkins, squash, tomatoes, cucumbers, turnips, strawberries, raspberries: Davrinol 50DF

  • cooking onions: Goal 2XL

  • asparagus, carrots, celery, dill, parsnips, potatoes: Loron L/Linuron

  • asparagus, peas, beans, cole crops, carrots, peppers, rutabagas, tomatoes, strawberries: Bonanza 480 or Treflan EC

  • asparagus, snap beans, potatoes: Eptam 8E/Sencor 500DF/Solu-Pak
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