Targeting your crop enemies

Is the future of crop protection environmentally friendly biotechnology?

Flea beetle is one of the pests a Manitoba researcher is targeting with biotechnology.

So far biotechnology in agriculture has driven the use of crop protection products through genetically engineered herbicide resistance.

But the next wave could displace at least some of those applications by opening up another front in the war on two familiar canola concerns — sclerotinia and flea beetle.

Mark Belmonte. photo: Supplied

Mark Belmonte, a professor of biological science at the University of Manitoba, told the Farm Forum Event earlier this winter that current crop protection products have their pitfalls.

He says there’s the fast-growing worries over resistance, built through many seasons of selection pressure, and the reality that many pesticides can also knock out beneficial organisms too.

“Some of these broad-spectrum pesticides as well as fungicides may be targeting other beneficial insects or organisms that could help promote plant growth as well as development,” Belmonte said.

Biotechnology can offer a more targeted and more environmentally friendly way to approach pest control. “Biotechnology kind of seems like a big scary word, but really what it’s doing is harnessing our knowledge of all things biology,” Belmonte said. “It’s harnessing our knowledge of everything that we can think about when it comes to different types of biological systems. These systems can be micro-organisms, they could be plants, or they could be animals.”

He noted while many insects share a common ancestor and therefore also share certain DNA sequences, they also have DNA sequences that make them different. These are the things that make them a different species.

“So we can start to formulate what’s considered to be next-generation pesticides/fungicides by harnessing our knowledge of the DNA sequences that are specific to a given organism,” he said. “The idea is that we are going to be able to target an individual pest, such as flea beetle, while protecting a number of beneficial insects such as the honeybee or other pollinators.”

There are two different approaches for applying biotechnology in pest control. The first one is a foliar application which is sprayed on the plant and the other is a transgenic approach within the crop itself that changes the plant’s DNA to make it deadly to the pest. Both have their advantages and disadvantages.

The advantages of a transgenic approach are that the plant makes the molecules, they are non-toxic, and they only target the specific pest/pathogen. The main disadvantage is public perception combined with regulatory delays.

The advantages of using a foliar spray are that the application process is familiar to farmers and that it’s easily transferable to a number of different crops. The disadvantage is higher costs associated with multiple treatments.

Belmonte and his colleague Steve Whyard, also at the University of Manitoba, have been working with this technology for nearly five years and developed a foliar spray as well as some transgenic plants to control flea beetle populations.

The results have been encouraging. Where over 64 per cent of canola leaves were consumed in the control group, where there was no treatment for the infestation, the transgenic approach saw only 24 per cent of the leaves consumed with a mortality rate of 67 per cent. With the foliar spray, only 18 per cent of the leaves were consumed, with a similar mortality rate (68 per cent) for the beetles.

“So we’re seeing some really promising results right now, not only in the lab, but also through next steps into the field,” said Belmonte.

Results for biotech treatments against sclerotinia were also encouraging. Within the control group, sclerotinia quickly overwhelmed the leaf — turning it brown and necrotic.

“However, once we spray the molecules onto the surface targeting different types of biological processes in the plant, we can see a profound as well as significant reduction in the amount of disease that’s found on the leaf,” Belmonte said.

Though the results are certainly good, as mentioned, biotechnology does have a somewhat sinister reputation to overcome.

In his ongoing effort to allay the fears associated with biotech, Dr. Belmonte and his team have published their findings in an open-access journal so that everyone can better understand the information.

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