Greenhouse Canada

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From the Editor: September 2018

Success hangs in the balance

August 21, 2018  By Greta Chiu

If there’s one key takeaway from this issue, it’s balance.

That point is driven home by our cover story this month (pg. 56), which features the research of Dr. Xiuming Hao from Agriculture and Agri-Food Canada. Based out of the Harrow research facility, his work on greenhouse energy and lighting shows what it means to achieve ‘balance’.

For instance, HPS lighting fixtures generate waste heat that leads to higher temperatures. The plants then transpire more, so they need more water and nutrients, and the greenhouse climate needs to be adjusted. A new balance must be found.


At Cultivate ’18, a conversation I had with Saul Cabrera of Greenspire Global stuck with me: crop protection is about balance too. What makes an integrated pest management strategy truly successful are the different practices involved, including scouting, adjusting greenhouse conditions, ensuring adequate nutrition and so forth. Applying a preventative fungicide is only one step, and that alone doesn’t necessarily lead to a healthy, well-balanced crop.

One of the keys to banker plant success? You guessed it – balance. Specifically the ratios of prey to beneficial predators at the beginning (pg. 34). Using non-crop plants to rear beneficial insects is an ingenious way to boost their population levels, ensuring they’re in full force by the time less-friendly bugs show up.

Another force that strives for balance in the world? Nature.

Turning to Dr. Roselyne Labbé’s feature (pg. 40), her team is working on identifying natural enemies of the dreaded pepper weevil. If Mother Nature has predators ready, then why not bring them into the greenhouse? Without products on the current market that can target immature stages of the weevil, this research update is one to take note of.

Another class of natural-borne assassins is the fungal pathogen. These infectious microbes have been isolated by scientists to create mycoinsecticides. Flip to Dr. Dan Peck’s feature for more on what they are, why growers should consider using them and how to make the most of their application (pg. 12).

 Key takeaway #2 in this issue is ‘know your greenhouse pests’. The feature on phloem feeders – aphids and mealybugs – is a prime example (pg. 20). The former responds well to systemic insecticides while the latter does not, underscoring the importance of scouting.

Then there’s Aphidius ervi, a parasitic wasp that some have given up on as ineffective against foxglove aphids. According to the study coming out of Vineland Research and Innovation Centre, one of the first steps to successfully using A. ervi is to release it as soon as you spot foxglove aphids (pg. 28). In other words, scout.

As Dr. Abida Nasreen points out, staff applying biocontrol strategies have to know how to use them. Are the biocontrols useful against the identified pests? Are the costs worth it? (Pg. 10)

And for something a little different, see our Q & A session with researchers Dr. Jaimin Patel and Leora Radetsky (pg. 46). They’re looking at the potential for visible and ultraviolet light in mitigating powdery and downy mildews – two common diseases in greenhouses. Who knows? There could be light levels on label one day for treatment against disease in the greenhouse.

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