CANOLA CROP DEVASTATED IN PRARIE PROVINCES DUE TO VIRUS - June 10th, 2025 CBC.com By John Doe Hectares of razed crops abound in Manitoba as a virus has decimated the crop. The culprit has been determined to be Barley Yellow Dwarf Virus, which is transmitted from aphids from the Southern United States. Usually this virus cannot over winter in Canada and is only brought to Canada from aphids carried by the wind. However due to climate change, the virus is now able to survive Canadian winters, thus attacking the crop at an earlier and more crucial stage in development. The Provincial Government of Manitoba has issued a state of emergency as the entire crop has been decimated, with losses numbering in the billions. According to agronomist Dr Smith, since the virus can now overwinter here, eradication is impossible and the whole canola industry in Manitoba may be a “relic of the past”. The preceding scenario is fictitious but the possibility of its occurrence is not beyond plausibility. The virus is a real threat to this crop currently but cannot overwinter so the late onset of this disease is not an immediate threat to the canola industry. Climate change and global warming is another reality that this scenario presents. However, despite the possibility of the perfect eclipse of these two aspects is not a death certificate for the canola industry in Canada but rather a catalyst for the industry to work on resistant strains and proper IPM to prevent disaster should this scenario become a reality. Therefore, to understand the scenario one must understand the canola crop, barley yellow dwarf virus and its transmission, the effect on global climate change on pest ecology, and finally the options available to combat this disease. Canola (Brassica campestris), is grown for its seeds that is in turn used to produce edible oil. What makes it ideal for human consumption is that it contains lower levels of erucic acid than other rapeseeds. It is also an excellent livestock feed because of its lower levels of the toxin glucosinolates. Canola was originally naturally bred from rapeseed in Canada by Keith Downey and Baldur R. Stefansson in the early 1970s, but it has a very different nutritional profile in addition to much less erucic acid. The name "canola" was derived from "Canadian oil, low acid" in 1978. A product known as LEAR (for low erucic acid rapeseed) derived from cross-breeding of multiple lines of Brassica juncea is also referred to as canola oil and is considered safe for consumption. Once considered a specialty crop in Canada, canola has become a major North American cash crop. Canada and the United States produce between 7 and 10 million tons of canola seed per year. Annual Canadian exports total 3 to 4 million tons of the seed, 700,000 tons of canola oil and 1 million tons of canola meal. The United States is a net consumer of canola oil. The major customers of canola seed are Japan, Mexico, China and Pakistan, while the bulk of canola oil and meal goes to the United States, with smaller amounts shipped to Taiwan, Mexico, China, and Europe. World production of rapeseed oil in the 2002–2003 season was about 14 million metric tons. Canola was developed through conventional plant breeding from rapeseed, an oilseed plant already used in ancient civilization. The word "rape" in rapeseed comes from the Latin word "rapum," meaning turnip. Turnip, rutabaga, cabbage, Brussels sprouts, mustard and many other vegetables are related to the two canola varieties commonly grown, which are cultivars of Brassica napus and Brassica rapa. The negative associations due to the homonym "rape" resulted in creation of the more marketingfriendly name "Canola". The change in name also serves to distinguish it from regular rapeseed oil, which has much higher erucic acid content. Hundreds of years ago, Asians and Europeans used rapeseed oil in lamps. As time progressed, people employed it as cooking oil and added it to foods. Its use was limited until the development of steam power, when machinists found rapeseed oil clung to water or steam-washed metal surfaces better than other lubricants. World War II saw high demand for the oil as a lubricant for the rapidly increasing number of steam engines in naval and merchant ships. When the war blocked European and Asian sources of rapeseed oil, a critical shortage developed and Canada began to expand its limited rapeseed production. After the war, demand declined sharply and farmers began to look for other uses for the plant and its products. Edible rapeseed oil extracts were first put on the market in 1956–1957, but these suffered from several unacceptable characteristics. Rapeseed oil had a distinctive taste and a disagreeable greenish color due to the presence of chlorophyll. It also contained a high concentration of erucic acid. Experiments on animals have pointed to the possibility that erucic acid, consumed in large quantities, may cause heart damage, though Indian researchers have published findings that call into question these conclusions and the implication that the consumption of mustard or rapeseed oil is dangerous. Feed meal from the rapeseed plant was not particularly appealing to livestock, due to high levels of sharp-tasting compounds called glucosinolates. Plant breeders in Canada, where rapeseed had been grown (mainly in Saskatchewan) since 1936, worked to improve the quality of the plant. In 1968 Dr Baldur Stefansson of the University of Manitoba used selective breeding to develop a variety of rapeseed low in erucic acid. In 1974 another variety was produced low in both erucic acid and glucosinolates; it was named Canola, from Canadian oil, low acid. A variety developed in 1998 is considered to be the most disease- and drought-resistant variety of Canola to date. This and other recent varieties have been produced by gene splicing techniques. An Oregon State University researcher has determined that growing winter canola for hybrid seed appears possible in central Oregon, USA. Canola is the highestproducing oil-seed crop, but the state prohibits it from being grown in Deschutes, Jefferson and Crook counties because it may attract bees away from specialty seed crops such as carrots which require bees for pollination. Canola was originally a trademark but is now a generic term for this variety of oil. In Canada, an official definition of canola is codified in Canadian law. Canola oil has been claimed to promote good health due to its very low saturated fat and high monounsaturated fat content, and beneficial omega-3 fatty acid profile. The Canola Council of Canada states that it is completely safe and is the "healthiest" of all commonly used cooking oils. It has well established heart health benefits and is recognized by many health professional organizations including the American Dietetics Association, and American Heart Association, among others. Canola oil has been authorized a qualified health claim from the US Food and Drug Administration ] based on its ability to reduce the risk of coronary heart disease due to its unsaturated fat content. Genetically modified canola which is resistant to herbicide was first introduced to Canada in 1995. Today 80% of the acres sown are genetically modified canola. Contamination of conventional canola crops from neighboring genetically engineered fields has been a serious problem for Canadian canola farmers. It is very difficult for farmers to grow non-GM crops because of the frequent contamination. The most high-profile case of contamination is Monsanto Canada Inc. v. Schmeiser, where Monsanto sued Percy Schmeiser for patent infringement because his field was contaminated with Monsanto's patented Roundup Ready glyphosate tolerant canola. The Supreme Court ruled that Percy was in violation of Monsanto's patent because the crops were growing on his land, but he was not required to pay Monsanto damages since he did not benefit financially from its presence. On March 19, 2008, Schmeiser and Monsanto Canada Inc came to an out of court settlement whereby Monsanto will pay for the clean-up costs of the contamination which came to a total of $660 Canadian. Also part of the agreement was that there was no gag-order on the settlement and that Monsanto could be sued again if any further contamination occurred. Introduction of the genetically modified crop to Australia is generating considerable controversy. Canola is Australia's third biggest crop, and is often used by wheat farmers as a break crop to improve soil quality. As of 2008 the only genetically modified crops in Australia were non-food crops: carnations and cotton. In 2003, Australia's gene technology regulator approved the release of canola altered to make it resistant to the herbicide Glufosinate ammonium. Barley Yellow Dwarf Virus is a virus that is transmitted via aphids to the following crops: barley, oats, wheat, maize, triticale, canola and rice. This virus is commonly referred to as BYDV, and its anatomy is that it is a positive sense singlestranded RNA. This means that its developmental orientation is in the positive direction of the RNA sequence. Within this species are two categories, Subgroup I and Subgroup II. Subgroup I has less severe diseases such as MAV, which is carried by grain aphid (Stiobion avenae). Subgroup II is commonly called Cereal Yellow Virus and it is often carried by bird-cherry aprids (Rhopalosiphum padi.) The pathology of the plant results when aphids feed on the phloem on the leaves of susceptible plants, in this case canola. Once inside of the plant, it uses the plant to reproduce its own genetic material. This process requires significant energy that is diverted from plant development, hence the symptoms of the disease. The cultivar of the affected plant is the major determinate of the severity of the symptoms, as is plant development stage, viral strain and environmental conditions. More often than not, it is mistaken for another disease or environmental condition. The onset of symptoms occurs about fourteen days after initial infection. Plants that are affected have the following symptoms: yellowing-reddening of the foliage, stunted growth, leaves that are in a rigid, upright position, reduction in root growth, delayed or no heading leading to a reduction in overall yield. Again, the virus is transmitted when the aphids feed on the phloem of susceptible plant leaves. During feeding, the virons go to the aphid hindgut. The coat protein of the virus is recognized by the hindgut antibodies and permitted passage into the hemolymph where it can remain for an indefinite period of time. However, the virus is incapable of reproducing in the aphid, making it only a carrier of the virus. Actively transported to the salivary gland, where it is excreted in saliva when the aphid feeds upon the host plant. In regards to how this disease spreads, there are two dispersal methods. One is dispersal by non-winged aphids that are pre-existing in the field, and colonize newly emerged crops, otherwise known as “green-bridge transfer”. This type is much more damaging to a crop because it infect during a time essential for growth of a new plant. The second method is by winged aphids migrating into crops from elsewhere. These then reproduce and the offspring spread to neighboring plants. This is the case with current infestation of Canola in Manitoba from airborne aphids from the warmer Southern United States. The effect on yields vary greatly depending on the host species and the variety that is being grown. Another variable to be considered is the dispersal method and the rate of infection. Severe losses occur mostly when the onset is during early development of the plant and yield losses can be up to fifty percent. Even at fifty percent, such losses can be disastrous to a grower because rotation is difficult for this pest due to the large number of host crops it can potentially infect. Management of this pest includes cultural methods such as tilling under these “green bridges” which prevents the non-winged aphids a corridor to move into a field or area. Insecticide is recommended to be applied ten days before cultivation but can also be used at crop emergence. Synthetic pyrethroid insecticides are the most effective at doing this task. Drilling dates prior to mid-October favors attacks from winged migrant aphids. However yield penalties may be experienced from late drilling. Insecticide sprays in this instance are therefore aimed at killing the aphids before significant spread can occur. The biggest catalyst for a potential problem is that if the virus is able to overwinter in Northern Latitudes, the infestation remains there in the soil and therefore is present regardless of planting date, making it difficult to prevent infestation. Due to the range of affected crops, rotation would not be viable because most cereal crops are susceptible to this disease. However, one must first understand the role of global climate change to better understand the scenario. One of the biggest threats to agricultural production in the 21st century is the prospect of global warming. The implications of this effect are much more than the crops but also the local ecology, which due to climate change is being altered. This leads to disruption in the ecological balance between pests and their predators. It will also allow pests into regions previously unaffected due to unfavorable conditions. According to the IPCC, the planet temperature has risen 0.3 to 0.6 degrees. The most rapid increase during this period has been 1925-1944 and 1978-1997. Despite the seemingly trivial increase in world temperature, this is not fully descriptive of the problem facing many ecological systems. Most of the areas with the greatest change are in the northern latitudes and occur mostly during the winter, where the range has changed by four degrees Celsius. This has effects on things such as reproductive processes and range of many species. Aphids date of flight migration has changed by 3-6 days (Fleming and Tatchel). If the warming trend accelerates, this could be earlier or allow a greater flow of aphids during warmer weather. Plant pathology depends on three factors, pest, environment and host to infect. Often referred to as the pest triangle, all factors are needed to be present to allow the disease to manifest. Should any of these factors become out of balance, the possibility for a disease epidemic becomes plausible. The major factors of climate change such as temperature, rainfall and carbon dioxide can severely impact the pest triangle. Changes in temperature potentially effect both host and pest. For example, rust becomes much more problematic in grass crops when temperature increases but some forages become more resistant to fungi as temperature increases. The temperate regions with winterkill are more likely to suffer problems from longer warm periods that are better suited for pathogenic activity. An example of this is a model for potato/tomato blight (phytophthora infestans) which demonstrated that this fungus reproduction and infection is most successful during periods of high moisture and temperatures from forty-five to eighty degrees Fahrenheit. If warmer temperatures onset earlier in the season, the threat of an earlier blight which could decimate the crop becomes more probable and the reality of higher pesticide use. The effect of increased moisture will vary depending on the crop that is affected. For example, some pests such as apple scab are more likely to infect when moisture is higher but some pests such as powdery mildew prefers lower moisture for infestation. More frequent and longer periods with increased moisture could result in periods of longer windows of favorable conditions for pests. Potential host crops that are limited by moisture to produce a greater canopy may be able to do so. This translates into more moisture being held in place, thereby increasing potential for pathogenic infection. The final aspect of global warming is increased Carbon Dioxide production, which effects are also dependent upon crop and pest. As mentioned before, elevated carbon dioxide could lead into greater canopy growth that would trap moisture. Lower rates of decomposition in plants could leave crop residue where pests can over winter, which could lead to earlier and more severe epidemics due to higher amounts of innoculum. Another dimension of increased carbon dioxide is that the host plant could undergo physiological changes that could make it more resistant to infestation. .In regards to the pest triangle, many events would have to align to make the scenario in canola the disaster that was presented. There would need to be increased moisture, temperature and carbon dioxide for all effects of this potential disaster to come to fruition. However, the effects can be avoided by farming practices and biotechnology. Many of these negative effects are beyond control but many cultural practices could prevent many of the worst effects. Row spacing and population density in the field could resolve the problem with a closed canopy facilitating moisture retention. If plants are growing bigger canopies and if planting takes that into consideration, the canopy will not fully close. This will allow moisture to escape and reduce but not eliminate the rise of pathogens. However weeds need to be taken into consideration or the prevention of one pest allows the emergence of another pest. Another cultural method of control is planting when effects are minimal. Even if a pest can overwinter in an area, there is a period where it will be less able to affect a young crop and planting accordingly should diminish risk. However, other pest pressures and climate still have to be considered when changing planting date to avoid the pathogen. The final way to manage the pest would be the use and development of resistant varieties as has been done in cereal crops. However in regards to barley yellow dwarf virus, there is not much to be done besides using a resistant variety if the scenario does become reality. This is why integrated pest management is very important in any cropping system. In conclusion, the scenario is pure fiction but using the pest triangle that includes a proper host, the pest itself and proper environmental conditions, one can see the possibility of such a scenario. The issue being is that there is not too much one can do to treat this problem of barley yellow dwarf virus. However, if cultural practices such as rotation of crops and spacing are used, the economic pitfalls of such a scenario could be made much less destructive rather than the catastrophic scenario previously mentioned. Therefore, to understand the scenario one must understand the canola crop, barley yellow dwarf virus and its transmission, the effect on global climate change on pest ecology, and finally the options available to combat this disease.