Greenhouse Canada

Features Biocontrols Inputs
The Latest in Whitefly Control

Next month’s Greenhouse Canada Grower Day is welcoming leading researchers and crop specialists to help you tackle one of the industry’s biggest challenges.

April 14, 2016  By Melhem Sawaya

Whitefly affects many crops.

Whitefly is proving to be one of the most difficult pests to control, mainly due to the lack of effective registered chemicals that can eradicate silverleaf whitefly. It is also due to the unwillingness of biological suppliers to bring Eretmocerus mundus back to the market – the only predator proven to be effective against this pest.

Growers are in limbo, dealing with the consumer who demands a 100 per cent pest-free product, a lack of biological predators, and the government that takes forever to register the new effective chemicals. The latter discourages chemical companies from going through the pains of registering chemicals here that are already registered in the U.S.

With all these roadblocks, growers still manage to deliver crops that satisfy the buyers but at a much higher cost, which translates into a lower profit margin. With this in mind, Greenhouse Canada – with advice from the horticulture industry – has decided to focus its annual Grower Day (June 15 in St. Catharines, Ont.) on whitefly issues. At the end of the program, every grower will have many new choices on how best to tackle the whitefly problem.


Grower Day speakers include a mix of researchers, extension specialists and suppliers willing to share their expertise and listen to grower feedback to know how to proceed in the future. If you have the same issues as many growers have with whiteflies, or you have any input as to what is needed, then this is a day that you do not want to miss.

Grower Day will conclude with a panel discussion featuring the day’s presenters. This is where concerns are voiced and questions answered to help growers deal with this major pest challenge.

Here is an overview of the program:

Dr. Michael Brownbridge of the Vineland Research and Innovation Centre – “The Tools at Hand Towards a Chemical-Free Environment.”

Sooner or later chemicals will not be an option, so making the most of what we have now will give us the tools to stay in business when that time comes.

Brownbridge will set the tone for the day outlining the available options – some you could already be familiar with and others that are new to you that could be applied in your operation.

Many of these tools will also be discussed by the other speakers, so you will have ample opportunities to ask questions for clarification. The tone for the whole day is a workshop environment, which means interaction between the presenter and the attendees is encouraged.

Bill MacDonald, an instructor with Niagara College – “Biostimulants: What Are They?”

MacDonald will share with us how biostimulants will be beneficial in our operations. He will discuss what they are, the differences and similarities between the various biostimulants, fertilizers and microbial fungicides. Biostimulants are an integral part of the quest toward a chemical-free greenhouse environment.

Dr. Rose Buitenhuis, of Vineland Research and Innovation Centre – “Biostimulants and Whitefly Control.”

Buitenhuis will make the connection between biostimulants and whitefly control. With more research, the application of biostimulants will be expanded to much more than whitefly control to include other crop issues, whether they are insects or diseases.

Here is her synopsis of these presentations. The morning session is: From the roots up: induced plant resistance to pests.

“Biocontrol against diseases is based on the use of beneficial micro-organisms and microbe-derived products. “These products have a direct effect against several plant pathogens, but can also induce a systemic defence response in the plant which can affect plant pests as well. In this project we tested several microbial products for potential positive or negative effects on the performance of greenhouse whitefly and spider mites and determined implications for pest IPM.”

The afternoon session is titled: How to make cutting dips part of an IPM system for poinsettia.

 “Starting clean is an essential part of any IPM strategy. This presentation demonstrates that poinsettia cutting dips reduced whitefly infestation levels at the beginning of the production cycle so that biocontrol strategies were more effective thereafter. We also determined the risks of disease transfer through the dipping process and calculated the cost-effectiveness of dips in a poinsettia IPM strategy.”

 Dr. Sarah Jandricic, Ontario Ministry of Agriculture, Food and Rural Affairs – “The Whitefly Basics.”

Jandricic will discuss the basics, including the biology, species of concern, and the proper identification of the different stages and types of whitefly. By getting a firm handle on what we are looking at and the life cycles, we can then ensure our efforts to control whitefly or any other pest or disease are much more effective.

Grower Day will also include an opportunity for some biocontrol companies to voice their opinions and outline the products that can help in controlling whiteflies and offer guidelines to handle the beneficials for best results. In any process there are three steps:

  • Know the process.
  • Learn how to use it.
  • Use it at the right time.

Ronald Valentin (Bioline), Dominique-Andre Demers (Biobest), Brian Spencer (Applied Bio-nomics) and Dr. Daniel Peck (BioWorks) will be sharing their knowledge, and attendees can pose questions to them.

Also leading a session will be Dennis Hitzigrath, general manager of Vivero Internacional. The company, based in Mexico, specializes in the production of plant cuttings. It produces a wide variety of pelargonium, poinsettia, New Guinea impatiens and dipladenia varieties. Vivero owns close to 100 acres of greenhouses and employs 800 people during the peak season.

In her second presentation, Jandricic will summarize the day and how growers can apply the information.

And last but not least, the panel discussion is where we can ask questions about the information that was presented for a better understanding of how it will fit in with the issues of whitefly control and plant biostimulants.

This is the part of the day in which grower interaction is so important.

Please bring your questions; there will definitely be at least one person on the panel who can provide the answer!

Grower Day includes a mini trade show of leading industry suppliers – a great networking opportunity.

The event is again being held at the St. Catharines Holiday Inn Hotel & Suites. There is plenty of free parking.Registration opens at 8 a.m., along with the trade show. The sessions will begin shortly after 9 a.m.

Grower Day has a microsite at

As I’ve said before, you are definitely headed for problems the minute you think you know it all. There are always better ways to do things. Continuous improvement is a must to thrive in the greenhouse or any business.

I can’t afford to miss next month’s Grower Day. How about you?

Melhem Sawaya is a consultant and research coordinator to the horticultural industry.

Print this page


Stories continue below