Science and Technology for Canadians

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Summary

The business of farming is changing. A lot of today's crops are grown indoors, in greenhouses. Farmers are learing new technologies to get the most out of the growing season. They also have to do a lot of learning about new pests.

Transcript of Video

Voice Over
The business of farming is changing. For one thing, it's becoming less and less of an outdoor job. A lot of crops today are grown indoors, in greenhouses. Farmers are being forced to learn how to use new technology to get more out of the growing season. They are also having to learn about some costly new pests, and a lot of that learning is being done in a lab.

Jay Ingram
Suppertime. And on the menu, a fresh salad -- topped off with juicy, red tomatoes.

It's a taste of sunshine in the middle of a chilly Canadian winter. And increasingly, shoppers are willing to pay a little extra for a home-grown luxury... That's right... home-grown.

The greenhouse industry in Canada has blossomed over the past five years -- and much of that growth is in hydroponic tomatoes. They're grown in a water-based solution, not in soil.

But even as they are battling foreign competitors for market-share, growers are also waging war against a common enemy in the greenhouse.

It took a big chunk of Larry LaBute's crop last season... took a big chunk of his profits too.

Larry LaBute
It's heartbreaking--but it's farming... that's what it is... and you just kind of lick your wounds... and get on with it the next year.

Jay Ingram
This is the enemy. Pythium -- a fungus that attacks at the root level, and thrives in water.

Pythium spreads by releasing microscopic spores. They can stick to the hydroponic equipment, get on the bottom of shoes -- even contaminate seeds. Once in, they swim through the hydroponic solution infecting roots and starving the plants. Then the losses add up.

Larry LaBute
Probably in the neighbourhood of about 10-15 percent, and then progressively getting worse as time goes on. Then you just have to determine the threshold level –whether it's worthwhile going on with the crop, or removing the crop and starting into a fall session.

Jay Ingram
This is the front line in the fight against Pythium –Agriculture Canada's Research Station in Harrow, Ontario, near Windsor. For three years Dr. Mike Tu has been developing a new method to help farmers.

Dr. Tu
This one, it's a healthy plant... see... there are lots of white roots -- the root is not affected by the disease. Now this one, in compared to the first one, this one has some disease that just began... now this one here is totally rotted out. You can see the difference here and here and here. Now, I remind you... all these plants are the same age.

Jay Ingram
Dr. Tu knows he will never be able to eradicate Pythium, but he does believe he can control it. And he's doing that without the help of chemicals. Fungicides to target Pythium are not approved for use in Canada.

Dr. Tu
When you use the fungicide... fungicide into the solution, the plants will pick it up -- and they will then... the water will be transpired into the air and the chemical will then deposit it into the fruits and you have a residue problem.

Jay Ingram
So Dr. Tu and his colleagues looked at Pythium in a new light--Ultra Violet light, to be precise.

UV light has long been used to sterilize everything from sewage sludge to drinking water. Dr. Tu wondered if it could disinfect hydroponic solutions... and it could... because it damages the genetic code of the spores.

Dr. Tu
The UV light is just like x-ray... there is some amount of penetration. So they will actually penetrate into the zoospores -- and kill the zoospores.

Jay Ingram
In fact it worked too well. Dr. Tu found that when he sterilized all the hydroponic solution in a system, he also killed off any good bacteria -- bacteria that promote plant growth.

So his team redesigned the way greenhouse tomatoes are grown.

There are two types of hydroponic systems--RockWool, and NFT, or Nutrient Film Technique.

Rock Wool is actually spun fibres of rock. It looks and feels like fibreglass insulation, and it acts like a sponge. The solution is pumped through an irrigation system. Rockwool soaks it up and holds it for the plant -- and the remainder drains into the environment. Pythium will spread slowly here, because the roots are somewhat isolated -- one plant per cube.

In an NFT system, Pythium can have a field day. The nutrient solution constantly flows over all the roots and the drainage is collected, then recycled back to the plants. Pythium spores are free to circulate and multiply. They spread quickly.

Dr. Tu's remedy was to marry the two systems. A base of individual rock wool slabs and cubes, with an NFT's recirculation system. He'd treat only the run-off with UV light.

Dr. Tu
... by combining the 10 percent or so of sterilized solution with 90 percent of new solution -- we can achieve complete recirculation without having any... you know... problem.

Jay Ingram
His system was 70-80 percent effective in controlling disease and preserved the good bacteria.

Dr. Tu
We cannot achieve a total control because the root... once the root is infected, it's there. But what we can do is we try to reduce the population in the circulation solution. So, as soon as the population is low, the amount of infection will keep low.

Jay Ingram
Now he's looking to the next step. Dr. Tu believes if he primes the rockwool slabs with bioagents -- bacteria that promote growth and naturally block fungal infection -- he can give the plants a fighting chance, even before UV light is used.

Dr. Tu
It's a pretty good control for this one here. You can see the root is almost very white here. And on the other one which we didn't have a biocontrol agent, the root are quite a bit rotted.

Jay Ingram
It all means healthier plants, and that translates into better yield, and a higher quality product. For greenhouse growers, and consumers alike, THAT'S the light at the end of the tunnel.