Canadian Scientists Develop Non-toxic Alternative

Biological Insecticide Working for North American Fruit Growers

Athletes, like those competing in the 2010 Olympic and Paralympic Winter Games, know that a balanced diet, rich in nutrients like those found in fruits and vegetables, is essential to fuel their success.

Around the world, consumers buy millions of pieces of fruit every day — supplied by farmers on almost every continent who work to produce the wide variety of quality tree fruits available today.

It’s not only consumers that enjoy fruit — harmful insects are always happy to sample the fruit of the farmers’ labour, jeopardizing their ability to produce a sufficient and quality harvest.

One of the most harmful of these insects is Cydia pomonell, or the codling moth, a hardy pest that affects apple, pear and peach trees.

Historically, most producers in Canada used broad spectrum insecticides to control this pest. But as concern increased over the undesirable and even harmful effects of these insecticides on the environment and food safety, the search began for more sustainable methods to control the damage caused by this insect.

In the year 2000, that search bore fruit, thanks to a collaboration between researchers in the private sector and the Government of Canada. The result was a biological control agent called Virosoft CP4, the first viral insecticide to be approved for agricultural use in Canada. It followed several years of research by Dr. Charles Vincent at Agriculture and Agri-Food Canada, and his collaborators at BioTEPP Inc.

Virosoft CP4 has proven to be very effective at controlling the codling moth, without any of the undesirable effects associated with traditional insecticides. It has no toxic effects on the environment or on mammals (including humans), and is completely harmless to other insects, including those that are beneficial to maintaining the equilibrium of the ecosystem. 

"The use of this biological insecticide helps to reduce the pollutant load associated with the effort to control the codling moth by a considerable amount,” says Dr. Vincent. “It is becoming especially popular with apple growers who have chosen the 'organic' chain, which limits the types of controls producers can use to control harmful insects.”

To be effective, the codling moth larvae must eat the granulovirus that is the active ingredient in the insecticide, so Virosoft CP4 is sprayed onto fruit trees before the codling moth larvae hatch. When the larvae emerge from their eggs, they swallow a little of this granulovirus when they eat their own shell, drink water droplets from the surface of the leaves or when they start eating into the surface of the fruit. More than 90 percent of the larvae will die in the first 24 hours, and most of the others in the days that follow.

By 2008, sales of Virosoft CP4 had exceeded $1 million, a 20-fold increase in just five years. The majority of this demand comes from the United States, where 95 percent of the Virosoft CP4 produced by Quebec-based BioTEPP is sold — compared to just five percent in Canada. Dr. Vincent says climate accounts for the difference — cooler, damper weather in Eastern Canada results in only two or three generations of the codling moth per year, and thus fewer applications of insecticide are needed.

Dr. Vincent and BioTEPP also worked for a number of years with Dr. Lawrence Lacey, a researcher with the U.S. Department of Agriculture (USDA). Together they were able to show that Virosoft CP4 is truly effective even in the hot, dry climate of the American West — a region where the climate means five or more treatments of conventional broad spectrum insecticides per year are needed to successfully control the spread of the codling moth.

Virosoft CP4 is now being used in Washington, Oregon, Idaho and Utah in the western U.S., as well as Ohio and Michigan in the Midwest. Altogether, this biological pesticide was used on close to 32,000 hectares (80,000 acres) of orchards in North America in 2008, mainly by conventional producers.

“We are only beginning to see the worldwide possibilities for this viral insecticide in terms of controlling the apple codling moth,” says Dr. Vincent. “With new collaborations to test the product, we could see Virofsoft CP4 available in more markets where climatic conditions are similar to those of the areas where it’s been proven effective in North America.”

Virofsoft CP4 is just another example of the innovative thinking and commitment to sustainability that is giving the Canadian agro-food sector a good medal reputation on the international scene.