A virologist with Agriculture and Agri-Food Canada (AAFC), in collaboration with breeders, has developed a way to speed up marker-assisted selection in the effort to identify potato virus Y (PVY) resistant material. The method – known as high-resolution melting markers, or HRM markers – has been used in other breeding programs, but Xianzhou Nie, a research scientist at the Fredericton Research and Development Centre, has perfected it so it can be used to select genetic material that is extremely resistant to PVY infections. As most growers know, PVY infection can devastate a crop, making the choice of seed important. Severe PVY pressure can cause as much as a 90 per cent yield reduction. Choosing seed that is PVY free, therefore, is the first step towards minimizing losses. However, aphids can also transfer the disease, which adds to the workload and cost of production when growers have to spray mineral oil to ensure the spread of aphid-transmitted PVY is minimized. The best solution from economic and environmental perspectives would be to have potato varieties that are resistant to PVY, which would also eliminate the spread of the disease. Nie hopes this research and development of a faster method to identify PVY-resistant and susceptible parent material and progeny will vastly improve and fast-track potato breeding. “Using HRM markers, we are identifying efficiently and accurately, markers associated with genes controlling PVY resistance in potatoes,” he explains. “If a potato inherits the resistance gene, it will not develop the disease. This will be very useful for breeders making selections in breeding programs.” Conventional breeding programs can screen thousands of crosses; it isn’t until the most promising are faced with PVY pressure that breeders know for sure if they have a potential disease-resistant variety. Traditional screening for PVY resistance is carried out mainly in the greenhouse by inoculating each and every offspring/progeny plant with the virus and then waiting for symptoms to develop and laboratory detection of PVY to be completed. By using the HRM marker technique (a procedure carried out in a laboratory as well), breeders will not only be able to identify and select parental material that is PVY-resistant or has “extreme resistance” prior to making crosses, but they will also be able to screen for progeny/offspring inheriting the resistance efficiently in the laboratory setting. Nie estimates that if 200 plants are bred using traditional selecting methods involving PVY inoculation in the greenhouse, it can take two to three months to determine which progeny, if any, are resistant to PVY. “Using the HRM marker method, we can screen for PVY-resistant plants in two to three days,” he says. By determining the value of using HRM markers in PVY screening, Nie says that in the future the method could be used to identify other diseases, or to isolate desirable traits. He says using HRM marker technology allows a researcher to run 96 samples in three to four minutes after amplification of the DNA pieces containing the markers. There’s no question the potential for breeding programs in the future is enormous. “In our breeding program at Agriculture and Agri-Food Canada, we anticipate the method being implemented for screening for disease resistance to speed up the selection process,” Nie says. Because the method was perfected at a public institution, it is not protected by copyright, which makes it accessible to any breeding program in the world. “We have provided the technology and now anyone can choose to use it.” Early in 2016, this new form of PVY resistance identification was tested on some of the latest clones bred at AAFC. The presence of the HRM markers that indicate PVY resistance was detected, which signals the potential varieties will be PVY-resistant. The breeders are now looking for germplasm that would have extreme resistance to PVY because those markers are present. Nie envisions a day when PVY-resistant potato varieties will be common, giving growers one less disease to worry about.
There’s no current technology to detect acrylamide precursors quickly and without destroying the spud, but a new technique developed by Lien Smeesters from the University of Brussels might help weed out potentially toxic potatoes before they even go to market. In Smeesters’ design, a laser uses infrared light to detect acrylamide, which scatters the light in a unique pattern, instructing the machine to knock the toxic potato out of circulation. | READ MORE
With planting season just around the corner, researchers at Agriculture and Agri-Food Canada are reminding home gardeners to take precautions to prevent the infection and spread of late blight. Planting clean and disease-resistant seeds is the best way to prevent the spread of late blight to other gardens and potato farms.What is late blight?Late blight is a disease caused by an organism that produces a white fuzz on the underside of leaves which releases millions of spores that float through the air to infect other plants. The spores land on a susceptible leaf, germinate, and cause brown oily lesions. The spores splash on the ground and infect potato tubers, which become brown and rusty looking, with a granular texture. Crop losses due to late blight can cost the Canadian potato industry tens of millions of dollars annually.Protecting the potato industry AAFC late blight specialist Rick Peters says taking steps to prevent the disease from infecting potato crops is important to help protect the health of the industry. He advises home gardeners to ensure their tomato seeds are resistant to the US-23 strain of late blight. Resistant seeds can be purchased at most garden centres. Certified disease-free seed potatoes can also be found at garden centres or purchased from a local seed potato grower. Peters says potatoes grown from last year’s garden or those bought from the grocery store are not suitable for planting as these tubers have not been tested and certified as disease-free and could be susceptible to a variety of potato diseases. AAFC has partnered with industry leaders to identify and track late blight strains in production areas across the country. Scientists are also looking at biological characteristics of the different strains including how they respond to treatments. This knowledge allows for better management and control of the strains in Canadian potato and tomato production areas. While scientists continue to study the disease, they maintain that an ounce of prevention is worth a pound of cure and home gardeners have an important role to play. If you spot a suspected late blight infection in your garden this season, please contact the Department of Agriculture, Aquaculture and Fisheries at 1-866-778-3762 for information on how to properly dispose of infected plants.
Syngenta Canada Inc. has announced the launch of Aprovia Top fungicide, offering Canadian potato growers a new tool for foliar early blight control and brown spot suppression. Early blight, caused by the Alternaria solani fungus, is found in most potato growing regions. Foliar symptoms include small, brown, irregular or circular-shaped lesions that form on the potato plant’s lower leaves later in the season. The disease prefers warm, dry conditions to develop, and can be more severe in plants that are stressed and weakened. Brown spot, caused by the Alternaria alternata fungus, is closely related to early blight and is found wherever potatoes are grown. Unlike early blight, brown spot can occur at any point during the growing season, producing small, dark brown lesions on the leaf surface. Aprovia Top fungicide combines two modes of action with preventative and early curative activity on these two key diseases. Difenoconazole (Group 3) is absorbed rapidly by the leaf and moves from one side of the leaf to the other to protect both surfaces against disease. Solatenol (Group 7 SDHI) binds tightly to the leaf’s waxy layer and is gradually absorbed into the leaf tissue to provide long-lasting, residual protection. Aprovia Top is available now for use in 2017 production. In potatoes, one case will treat up to 40 acres.
For potato growers around the world, common scab is a constant vexation. Causing millions of dollars in losses each year, common scab is difficult to control. Recent research, however, has identified options for suppressing the disease, if not getting rid of it all together. Some of the research centres on what soil properties make scab more conducive, while other studies look at natural products that can slow the spread. “Scab is a troublesome disease,” admits Robert Coffin, a potato agrologist in Prince Edward Island. “There are different genetic strains of scab as well; there are at least five species, so it’s a constant problem. For example, common scab and powdery scab are two different organisms, but both diseases can cause losses in sales because scab infested tubers cannot be sold for table, processing or seed.” While large strides have been made to control scab, such as using natural bacterial products, seed treatments, soil fumigants, and attempts to find genetic resistance, the disease continues to confound researchers and growers alike. Management options are limited but several help, such as planting varieties with “reasonable resistance” or fumigating the soil, which has proven successful, although is it not permitted for use everywhere. Some diseases can’t survive in the soil without a host, according to Claudia Goyer, a research scientist with the Agriculture and Agri-Food Canada (AAFC) Fredericton Research and Development Centre. But Goyer says scab can live successfully in the soil without potatoes being present, making it a problem when potatoes are planted. “The scab bacteria grows on organic matter, like plant residues,” Goyer explains. “What makes it difficult is there are areas of fields that are infested while others are healthy and we do not know why. We now believe there is something different between scab-infested or healthy areas, like soil properties or microbial communities, that could be conducive or suppressive to scab.” To test this theory, Goyer and her colleagues examined either healthy or scab-infested areas of nine potato fields in Prince Edward Island, New Brunswick and Quebec. The same variety of potato – Red Pontiac – was grown in each field and the team gathered soil samples three times during the year. Several soil properties (including pH, organic carbon, micronutrients and soil texture) were measured to attempt to determine the difference between the soils that contained scab and those that didn’t. “We are trying to learn if it is something physical, chemical or biological, such as soil microbial communities in the soil, that promotes scab,” Goyer explains. “Some microbial communities suppress scab.” Not surprisingly, she also discovered that the greater the presence of the scab bacteria, the greater the disease pressure. “We are still analyzing our data, but we are seeing a correlation between scab and pH levels, with more scab in neutral pH soil. We are also seeing that soil carbon to nitrogen ratio, and nutrients including potassium, magnesium and calcium, were correlated with scab severity, but we aren’t sure why yet.” Advancements in soil science are making it possible for the researchers to analyze soils more effectively and they are also able to assess new control options more efficiently. Coffin conducted research on Microflora Pro, a natural product that contains two species of Bacillus bacteria. He says the product worked really well in 2015, but the results were inconsistent in 2016. “Bacterial cultures don’t always stay stable in storage or in soils,” Coffin explains. Therefore, understanding scab and how it infects soil, and continuing work to breed resistant potato varieties, would offer better disease management options. Goyer’s work on analyzing soil and understanding why certain fields are infested with scab may also help the developers of microbial products create formulations that will work best. The advent of more sophisticated soil science research is paving the way for a better understanding of what bacteria will work best in soil. “We can truly study soil communities so much more than we could years ago using next-generation sequencing,” Goyer says. “We can see how diverse the soil bacteria and fungal communities that are present in soil are now because of the depth of sequencing. We can capture most of the species present with this approach.” This type of work will help explain the difference in the diversity of soil microbial communities between healthy and scab-infested areas in potato fields. “Once we understand better what a healthy soil microbial community is,” Goyer continues, “we can see if we can change soil microbial communities so they suppress scab using agricultural practices, inputs like manure and compost, or use of natural bacterial products that suppress scab. “In the future, we will be able to harness the power of the soil,” Goyer says. “We may be able to manipulate bacteria communities to improve all crops and we could use them to suppress disease.” Both Goyer and Coffin approve of the idea of using one bacteria to control another. In theory, the best solution would be to combine several bacteria into one product to help with stability, reduce the potential of resistance developing and, possibly, offer balance in the soil. But with so many variables, it takes a great deal of research to get it right. Goyer says one possibility is that a certain bacteria could be targeted to where it is needed most, similar to the way precision fertilizer application works. Higher amounts of scab-fighting bacteria could be targeted to where soil tests show a high concentration of the disease, and less could be added where scab pressure is low, creating an overall balance across the field. “Progress is being made,” Coffin says. “With 30,000 to 40,000 genes in a potato plant, it’s like a giant Rubik’s cube when trying to breed a potato with all the desired traits.” Of course, scab resistance is only one of the desirable traits, which makes finding a solution in the soil another option for controlling scab – and one that Goyer believes shows great promise going forward.
Researchers at the Texas A&M AgriLife Research plant pathology team have intentially infected potato plants with the bacterium that causes zebra chip in order to identify potato varieties with genetic resistance. | READ MORE
Nov. 29, 2016, Canada – Canada's potato production was 105.2 million hundredweight (4.7 million tonnes) in 2016, up 0.5 per cent from 2015, according to the latest report from Statistics Canada. Production in British Columbia increased 41.8 per cent to 315 hundredweight per acre. Ontario, which experienced extreme summer heat and drought, saw production and yield fall 17.2 per cent compared with a year earlier. Harvested area edged down 0.2 per cent from 2015. In 2016, Prince Edward Island represented 24.5 per cent of total potato production and Manitoba represented 21.3 per cent.
Some P.E.I. potato farmers have had to wait longer than usual to finish their harvest because of recent wet weather, according to the P.E.I. Potato Board. | READ MORE
Ambra variety potatoes harvested by C&V Farms in October. Photo courtesy of Eugenia Banks. Oct. 27, 2016, Ontario – Each growing season is different, but the 2016 season was unlike any season seen before in Ontario. Planting started later than usual due to the cold weather. The early crop planted by the middle of April in southwestern Ontario took more than three weeks to emerge due to cool soil temperatures. Growers were caught off guard when snow fell by the middle of May. The season was off to a bumpy start. There was only limited rain up to the end of May. Then the heat and drought started relentlessly – too early in the season. Studies have shown that a healthy crop of potatoes needs an inch of rain a week. That adds up to about 16 inches of rain from May through August for the potato crop to show its full potential. Environment Canada data indicates that the water deficit in Norfolk, Simcoe and Dufferin counties was above 60 per cent. Norfolk County was the hardest hit by the heat and drought, with a total rainfall close to four inches near Delhi. Where available, irrigation was the order of the day during the summer. However, growers could not keep up with irrigation due to the extremely high evapo-transpiration rate. Irrigation increased the cost of production dramatically. By July, there were reports of some irrigation ponds that were completely empty and not filling up. One producer said, “With the heat and drought we are experiencing, irrigation is simply keeping the crop alive. Rain water does way more for the crop than irrigation.” There were many days in June, July and August when the temperatures were above 30 C. Such heat puts the potato plants in a dormant state, unable to photosynthesize efficiently, the activity that keeps plants functioning well. Some rainfall by the middle of August did not help the early crop, which was too far gone to benefit from rain. Ontario Potato Distributing in Alliston started packing early potatoes from Leamington on July 19. Quality was excellent. The harvest of the early crop continued in August but yields were down at least 50 per cent in non-irrigated fields. In irrigated fields, yield reduction was at least 35 per cent. Dry weather brings good quality. Diseases such as late blight, pink rot and leak did not develop. These diseases, also known as storage rots, reduce quality and can cause significant storage losses. Hot, dry weather also induces second growth. A few table varieties with short dormancy aged rapidly in the field and showed some sprouting before harvest. Mark VanOostrum reports that the chip processing crop yielded as low as 60 per cent of normal yield. The best yields were reported from the Shelburne area in the late-planted crop and late-season varieties. Harvest was difficult, because it took more than five to six weeks to get good skin set after topkill or natural death. Because the fall was very warm, storages temperatures are just starting to drop below 13 C. Typically, the temperature would have been down to 9 C on many bins for a few weeks by this time of the year. Higher storage temperatures will age the crop (one that was already aged in the field due to the heat and drought). The processing of the storage crop started earlier than anytime in recent history due to the shortage of field fry crop. Some heat necrosis was seen in Atlantics, but minimal in other varieties. So far, the quality of the storage crop has been very good. Some stem end sugar defect is present, but less than normal for this early in the storage season. One real concern is how the long-term effect of the heat and drought stress affect the chipping quality. Stem end sugar defect incidence and severity is highly correlated with extreme heat, and the question remains: will we be able to burn off all the stem end? Also, the heat and drought stress is correlated with chemical and physical aging. Will a variety that typically has a seven-month life span be shortened by weeks or months? Time will tell. By Thanksgiving, nearly all the table and processing crop had been dug and stored with no risk of storage rots. Ontario potato growers will remember 2016 as one of the hottest and driest year in Ontario. Our potato growers should be commended for their resilience and capacity to produce a high-quality crop in what was an extremely difficult growing season.
Oct. 6, 2016, Ontario – A quick survey indicated that about 80 per cent of the provincial potato crop has been harvested by Oct. 5, according to Eugenia Banks, Ontario potato specialist. On the chipping front, Mark Van Oostrum from WD Potato expects that most processing growers will be done by Thanksgiving. Growers in the Simcoe, Ont., area are close to completing the harvest. Joe Lach, who farms near Delhi, Ont., will finish this coming week, and told Banks his remaining potato crop is all sold. About 60 per cent of the acreage near Shelburne, Ont., has been dug. This area plants a bit later than other areas due to cooler spring weather and lower soil temperature. On Oct. 5, Banks harvested a variety trial in Honeywood, Ont. Standard processing varieties such as Lamoka (chipping) and Waneta (chipping and table) did very well. There was no second growth or tuber malformations. By contrast, many of the new varieties under evaluation showed the effects of a hot, dry summer: second growth, bottlenecks, cracks and knobs. 2016 was a great year to see how new varieties perform under heat and water stress.
Sept. 23, 2016, Prince Edward Island – The P.E.I. Potato Board is still concerned about saboteurs two years after needles were found in Island produce, but it's grateful to Islanders who are keeping an eye out for suspicious activity. | READ MORE
While Canadian appetites for sweet potatoes have skyrocketed in recent years, production in Eastern Canada remains small.
New Zealand farmers have invented a new kind of potato they claim has 40 percent less carbs.
Whether its disease resistance, tolerance to stress in the environment or better cold-storage capabilities, research scientists have been incorporating wild potato genetic resources into breeding lines for years to develop more resilient potato varieties. At Agriculture and Agri-Food Canada's (AAFC) Fredericton Research and Development Centre, this practice is being increasingly refined in order to meet the needs of the industry which range from higher yields to disease and drought resistance.
Benoit Bizimungu is quick to identify top breeding priorities for implementing marker-assisted selection at Agriculture and Agri-Food Canada’s (AAFC) Fredericton Research and Development Centre.
More Growing Forward 2 funding has been put in place to help expand markets for Canadian potatoes. The project, funded under the AgriMarketing Program, provides the Canadian Horticultural Council with up to $274,714 to help grow foreign and domestic markets for Canadian potatoes through trade shows, targeted advertising, incoming missions, market research and development, and product promotion. This investment is part of the federal government's plan to help Canadian farmers expand markets at home and abroad. Canadian potato exports are currently $1.6 billion dollars annually.
It is rare in biology that a single trait can answer questions spanning several fields of research. One such trait is plant biology’s “leaf mass per area,” a simple measurement calculated by weighing a dried leaf and dividing by its original fresh area. Leaf mass per area, or LMA, which has been measured in thousands of studies, is used in nearly every field of plant biology to make predictions of many processes and properties such as leaf photosynthetic rates, nitrogen content and plant environmental preferences. However, despite the simplicity of the measurement of leaf mass area and its value for predicting so many aspects of plant biology, the relationship of leaf mass area to leaf structure – the cells and tissues that make up a leaf, and their numbers and dimensions – has not previously been determined. Researchers at the University of California – Los Angeles (UCLA) have developed a mathematical equation for leaf mass area that will help to determine what drives plant behaviours based on their cells. The research, which has important implications as plants adapt to a warming environment, is published online by Ecology Letters, a prestigious journal in the field of ecology. “The great diversity of leaves in size, shape and color is dazzling, and yet, it is nothing as compared to the diversity of cells and tissues inside,” said Lawren Sack, a professor of ecology and evolutionary biology and the study’s senior author. “However, we have lacked equations to relate this inner diversity to overall leaf behavior in an exact way.” Grace John, a UCLA doctoral student in ecology and evolutionary biology and the study’s lead author, conducted a detailed study of the anatomy of 11 species growing on the grounds of UCLA that included iconic species from many ecosystems, such as the toyon or hollywood, and a species of tea from Japan. She measured cross-sections for the sizes and numbers of cells of the different leaf tissues and she stained whole leaves to measure their vein tissues. The team then developed a theoretical approach based on geometric principles to derive an equation for leaf mass area, taking into account the dimensions and numbers of cells of each type in the leaf. The biologists’ strategy was to create a powerful mathematical equation that predicts the leaf mass area from just the structures inside the leaf. This equation was able to predict the leaf mass area of the diverse leaves with extreme precision. The team, which collaborated with researchers in Spain, Germany and Australia, also used the mathematical approach to explain the difference between evergreen and deciduous leaves in their toughness. “If you grab a leaf from a California evergreen shrub and a deciduous sycamore tree, you can feel the difference in toughness, but it’s more challenging to explain why,” John said. “With our approach, we show that evergreen leaves tend to be tougher and live longer because they have larger and denser cells.” “The implications of these kinds of equations are enormous,” Sack said. Because a lower leaf mass area generally leads to greater plant growth and productivity, and a higher leaf mass area can contribute to stress tolerance, this approach can resolve how differences in cell traits among species affect productivity and tolerance to environmental stress given climate change. “It is hard to exaggerate the importance of LMA in plant biology — it’s like body size in animal ecology, facial symmetry for the psychology of attraction, and sprint speed for NFL wide receivers,” John said. “LMA has really been the ‘uber’ variable for understanding plant economics, productivity and function.” Sack described the approach as a game-changer for designing crops with higher productivity or greater stress tolerance. “We are aiming to usher in a new era in the science of leaf economics by merging plant anatomy with mathematics and ecology in a unique way,” he said.
One of the more than 70 USDA studies in Maine looking at the effects of crops like mustard, rapeseed and barley in potato rotations. Photo by USDA-ARS If you’re dealing with some tough soil-borne diseases, adding canola, mustard or rapeseed to your potato rotation could help. That important finding emerged from recent potato rotation studies in Maine, led by Dr. Bob Larkin, a research plant pathologist with the United States Department of Agriculture (USDA). Over the last 12 years or so, the USDA researchers have conducted more than 70 trials to investigate the effects of different rotations on soil-borne diseases in potatoes and on potato yields. Although the results varied from year to year and field to field, overall, Larkin and his research team found that crops in the Brassicaceae family, such as canola, rapeseed and mustard, consistently reduced potato diseases like black scurf, common scab and Verticillium wilt, and significantly improved potato yields. Now researchers in Atlantic Canada will be examining the effects of Brassica crops as part of a major potato rotation project. Three-pronged attackLarkin explains there are three general mechanisms by which rotation crops may reduce soil-borne diseases – and Brassica crops likely act in all three ways. “The first mechanism is that the rotation crop serves as a break in the host-pathogen cycle,” he says. “This mechanism is in effect any time you have a rotation crop that does not have the same pathogens as your host crop. This is a general strategy of increasing rotation length by adding other types of crops. The longer the time between your host crop, the more its pathogen population declines.” “The second mechanism is where the rotation crop causes physical, chemical or biological changes in the soil environment,” Larkin says. “It may stimulate microbial activity and diversity, it may increase beneficial organisms, and things like that, which then help compete with pathogens and reduce pathogen populations.” This mechanism varies with different rotation crops. “The third mechanism is where the rotation crop has a direct inhibiting effect on either particular pathogens or general pathogens,” he says. The rotation crop may release suppressive or toxic compounds in its roots or residues, or it may release compounds that stimulate certain beneficial microbes that suppress pathogens. Only some crop species have this mechanism. The first mechanism by itself may not be very effective for controlling some soil-borne pathogens that can survive for many years without a host plant. Brassicas are well-known for the third mechanism. They contain compounds called glucosinolates, and when Brassica plant materials are incorporated into the soil, the glucosinolates break down to produce other compounds, called isothiocyanates. Isothiocyanates are biofumigants that are toxic to many soil fungi, especially fungal pathogens, weeds, nematodes and other pests. Larkin’s research shows Brassica biofumigant activity is greatest when the crop is incorporated into the soil as a green manure. However, even when a Brassica crop is harvested and then the remaining crop residues are incorporated, there is still some biofumigant effect. The amount of the biofumigant effect also depends on the Brassica crop’s glucosinolate levels; canolas have relatively low levels, rapeseeds somewhat higher, and mustards have the highest. “With any of those Brassicas, you will get some benefit from incorporating the crop residues. And it is a measurable and real effect on both potato yield and on reduction of potato diseases,” he notes. As well, Larkin’s studies indicate Brassicas also provide the second mechanism. “Brassicas seem to have an ability to alter soil microbial communities in different ways which is not necessarily related to their amount of glucosinolates or their ability to act as a biofumigant. I think the aspect of how they change the soil microbiology is equally important to their biofumigant effect,” he says. For example, the USDA researchers found that canola and rapeseed sometimes do a better job at reducing black scurf (Rhizoctonia solani) than some of the higher glucosinolate mustards, and the effect on black scurf works even without incorporating the Brassica crop. However, Larkin’s studies also show that managing some other diseases – like powdery scab (Spongospora subterranean) and Verticillium wilt – requires a full green manure. Two-year rotation is too shortIf disease suppression is a major goal of your potato rotation, then Larkin’s research results provide some key factors to consider. First, a Brassica’s disease suppression effect won’t last forever, so the potato crop should immediately follow the Brassica in the rotation to get the greatest benefit. Second, a two-year rotation will not effectively reduce disease in the long run. Larkin found that no matter what crop was in a two-year rotation with potatoes, certain pathogens tended to build up over time. For example, in one 10-year study the researchers compared two-year rotations in fields where common scab and Verticillium wilt were not problems at the beginning of the period. But by the end of the study, both diseases had become substantial problems in all of the two-year rotations. The canola-potato and rapeseed-potato rotations had significantly lower disease levels than the other rotations, but they still had gradually increasing amounts of common scab and Verticillium wilt. “So we recommend a three-year rotation as your first line of defence, and then including a disease-suppressive rotation crop in one of the years of that three-year rotation,” Larkin says. A Brassica green manure could be a good choice for the disease-suppressive crop, or you could grow a Brassica as a full-season crop and follow it with a disease-suppressive cover crop. “The addition of a cover crop like winter rye or ryegrass, in combination with your Brassica, can provide a significant addition to the disease reduction,” he notes. Even though the grower would not be earning any direct income from a green manure or a cover crop, these options can be valuable tools to get serious soil-borne disease problems under control. “That’s really how we first got into this research,” Larkin explains. “Some potato growers [in Maine] had some soils with substantial disease problems, and they wanted to try whatever they could to get those soils back to where their potatoes would be producing better. So they were willing to give up a seasonal crop for a year or two, to try to get the pathogen populations down to controllable levels.” (Two seasons of a green manure might be necessary if the field has very high pathogen populations.) A third factor to consider is whether the rotation crops share any pathogens with potatoes. In Maine, the only shared pathogen that increased in potato-Brassica rotation trials was sclerotinia. In his own studies, Larkin hasn’t had any sclerotinia issues because sclerotinia is not common in Maine potato fields. However, a researcher at the University of Maine found two fields with sclerotinia and did some rotational trials there. Sclerotinia increased in those two fields when canola or rapeseed was in a rotation with potatoes. “So if you have a field with a history of sclerotinia problems, then a Brassica may not be the best rotation crop for you,” says Larkin. Alternatively, adding a cereal crop to a potato-Brassica rotation may help because cereals are not susceptible to sclerotinia. Maritimes rotation projectThe major potato rotation project now underway in Atlantic Canada is examining various crop options including canola and some other Brassicas. Dr. Aaron Mills, a research scientist with Agriculture and Agri-Food Canada (AAFC) in P.E.I., is leading the project. He is conducting trials at AAFC’s Harrington Research Farm in the province, involving nine different three-year rotations. The project is funded under Growing Forward 2, with support from AAFC and the Eastern Canada Oilseeds Development Alliance Inc. McCain Fertilizer division is collaborating by conducting a similar study in New Brunswick. Generally, the project’s three-year rotations involve a year of potatoes, a year of another high-value crop, and a year of a more diverse crop mix or a biofumigant crop. “We’re looking at canola, soybean and corn [as the high-value crops], and at other, more diversified phases in the rotation, including blends of a Brassica, a grass and a legume all planted at the same time,” Mills explains. He notes, “The canola acreage is increasing slightly in Prince Edward Island, it is one of the higher-value oilseed crops, and it does very well under our climate. And it’s important to diversify the cropping system, so if you can add in a different crop and it’s a higher value crop, then that’s a win-win situation. “Canola has also been touted to have some biofumigatory effects, and the Brassicas in general produce certain compounds shown to have effects on diseases and insect pests,” Mills says. “Buckwheat is another [crop that supresses pests], based on research by my colleague Dr. Christine Noronha, so we’re also including buckwheat in the trials.” Mills and his research team will be scouting all the crops in the different rotations for disease and insect pests. Sclerotinia is one of the issues they’ll particularly watch for. Mills notes, “We are starting to see an increase in sclerotinia [in P.E.I.], and a lot of the higher value crops in these rotations are hosts for sclerotinia.” Along with collecting data on crop yields, diseases and insect pest issues, the researchers will also be monitoring such factors as crop biomass and soil organisms including nematodes. And Dr. Judith Nyiraneza, an AAFC nutrient management specialist, will be tracking nutrient dynamics in the soil. The researchers conducted preliminary work in 2013, and 2014 was the project’s first full year. The current funding will take the project to 2017-18, but Mills hopes to run it for nine to 12 years. “You can’t really look at the trends until you get at least a couple of phases of each rotation. So one of the big determinants for the project’s success is how long we can run the rotations,” he says. Putting it all togetherThe effects of different rotation crops on potato diseases and yields may differ somewhat from region to region. Mills emphasizes the importance of evaluating rotations in different regions: “P.E.I. soils are different than those in Ontario or out west, and how the crops respond is not exactly the same.” Mills’ overall advice for effective potato rotations is that more diversity is better. “From what we’ve seen so far with some of our other studies, it’s all about increasing the crop diversity. You can increase the length of the rotation by adding different crops. Or, if you have a shorter rotation, you can increase [the in-year diversity]. That seems to show some benefits to the soil and to the organic matter especially,” he says. Similarly, Larkin advises using multiple rotation-related practices for enhanced disease suppression. Examples include: increasing the rotation’s length, adding crops that also have the second and third mechanisms of disease suppression, and including cover crops and green manures. His research shows that, although these practices will not completely eliminate potato diseases, they will reduce soil-borne potato diseases and improve potato yields. As well, these kinds of sustainable practices provide other long-term benefits for a farm’s production capacity and potential longevity. These benefits include improving overall soil health, enhancing soil microbial diversity and activity, increasing soil organic matter and building a healthier agro-ecosystem. “All these practices are components of making a better, more sustainable system,” Larkin says. For potato growers in Maine, Larkin’s general rotation recommendation is “a three-year rotation, with one year of a grain such as barley, then a cover crop like ryegrass or winter rye, then a Brassica, which could be a mustard green manure or a harvestable oilseed Brassica crop, and then potato in the third year of the rotation.” He notes, “That recommendation is based on a lot of different studies looking at what is the best system for reducing disease, what is the best system for improving soil quality. Now [in our current studies] we are trying to combine those into a rotation that incorporates aspects of all of those things and seeing if it really does everything we hoped it would.”
Sept. 25, 2014, Prince Edward Island – A new method of applying fertilizer to potato crops, with the intent to grow a more desirable potato while cutting down on costly fertilizer waste, is showing promise in Prince Edward Island, reports The Guardian. | READ MORE
Southern Alberta is well known as cattle country, but the region also is home to significant commercial potato production. Now, a partnership between a potato grower and cattle producer has proven to be a fortuitous – albeit rather unorthodox – opportunity to unite the two industries for mutual benefit. Harold and Chris Perry are co-owners of the Kasko Cattle Company, with feedlot owner Ryan Kasko, on 10 quarter-sections of land surrounding the Kasko Cattle Company feedlot east of Taber, Alta. Kasko owns and operates the feedlot itself, which raises about 14,000 head of cattle annually. Harold Perry says they partnered with Kasko in the recent purchase of the land surrounding the feedlot partially because it provided them with a ready supply of manure that they could convert to compost for use in their potato production. The potato producer benefits primarily from the nutrient and micronutrient value delivered by the feedlot’s manure when it is applied on potato cropland in the form of compost, while the feedlot has a handy place to dispose of its significant accumulation of manure right nearby. The feedlot owner delivers the raw manure to a dedicated composting site with good drainage control where the potato producer converts it to compost. It is land applied in October and worked in before the potato hills are created for next year’s planting. The Perry family’s expertise, which includes Harold and Chris’ father, Gerald, is in producing crops such as potatoes, sunflowers and peas on a total of 4,600 owned and rented acres. Their business is headquartered close to the town of Chin, about 40 kilometres from the feedlot – a typically hot, dry climate requiring irrigation, with plenty of frost-free days. The Perrys have a contract to produce 13,500 tonnes of potatoes for Frito Lay and 8,500 tonnes of potatoes for McCain Foods on about 1,300 acres that are under irrigation for that purpose. For the past decade, the Perrys have used cattle manure compost as fertilizer in their potato-growing operation because of the nutrient and microbial benefits they’ve realized from using it. Harold Perry says they observed with growing potatoes on virgin potato growing soil versus soil that had been under cultivation previously in a four-year potato crop rotation that there was a dropoff in potato production on soil where potatoes had been grown in the past. They discovered that using compost on the potato rotation land not only provided organic fertilizer to the crop but also worked as an excellent soil amendment, adding many micronutrient and biological unknowns to the overall quality of potato-growing land that really made a difference in commercial potato production. “We wanted to try compost because that is the natural way that things work,” says Perry. “When the buffalo were here, they ate and manured the grass at the same time, and that’s how the natural cycle worked. Fertilizer prices have also helped because compost makes sense if you go strictly by dollars. The cost of putting the amount of nutrients you put on your soil using compost is less than if you were to purchase that at a fertilizer dealership.” Composting the manure deals with that issue, and it is also more economical to transport nutrients in this form than as raw manure. The Perrys can attest to that fact. “Good compost has about 60 per cent of the weight of raw manure,” says Perry. “So if you get too far away from the feedlot, then the trucking just kills you.” Research being conducted by Agriculture and Agri-Food Canada, specifically in Summerland, B.C., also is showing that the addition of compost could help in the prevention of verticillium wilt, also known as early dying syndrome. Potato crops infected with this pathogen will typically see the tops of potato plants die off between early August and September, which can have a devastating impact on potato production in the case of a bad outbreak. The pathogen enters the plant through root lesions. The root lesions are caused by nematodes that live in the soil and feed on the roots. So far, what the B.C. research has shown is that the addition of compost enhances the presence of a fungus that feeds on the nematodes, thus reducing the amount of root lesions and closing the pathway for the verticillium wilt pathogen to enter the plant. Results so far have been promising, although the theory hasn’t quite been proven yet, according to Dr. Frank Larney, research scientist in the area of soil conservation with Agriculture and Agri-Food Canada (AAFC) at the Lethbridge Research Centre in Alberta. Before the Perrys became partners in the feedlot, they were purchasing their compost from a commercial supplier. It was partially because of compost quality issues that they agreed to invest in land surrounding the Taber area feedlot with Ryan Kasko so they could acquire their own supply of raw cattle manure to manufacture compost. The Taber feedlot and surrounding land were also near their potato growing operations, so all the pieces conveniently fell into place. Harold Perry is in charge of compost production. “If I have a goal, it’s to have healthier soils, for healthier crops, for a healthier population,” he says. The Perrys pay Kasko for the cattle manure, and he in turn hires a custom contractor to deliver the raw manure to the compost production site. The custom manure hauler creates the windrows needed to produce compost. During the first year of compost production, the feedlot delivered about 9,000 tonnes of manure to the site. Delivery of the manure resulted in four windrows measuring a distance of about half a kilometre each. Once the windrows were created, Perry began monitoring the conversion process and used his compost-turning equipment as needed. He acknowledges feeling a bit anxious about delving into compost production because of the science required to ensure that the biological organisms have a healthy environment to carry out the conversion process but adds that learning to compost has been an enjoyable experience. To prepare himself, he took a composting course offered by Midwest BioSystems. The conversion process takes from July to mid-October. To turn the compost, Perry purchased a 14-foot wide, pull-type, Sittler compost turner, which retails for about $45,000. He was able to recoup about half the cost by applying to a government program called the Growing Forward Manure Management Program. He checked the heat and moisture content in the composting windrows regularly to ensure that the organisms were working in an optimum environment. He also purchased a Sittler water wagon that can be towed along with the compost turner so that moisture can be applied to the windrows as needed. Perry says he turned the compost six or seven times with the main determining factor being when the temperature in the compost heap reached 160 F. At the beginning, the turning was done every four or five days because of the strong biological activity underway. Ideally, the conversion process should take 10 weeks, but Perry says he prefers to wait 16 to 20 weeks. As part of the Perrys’ adventure into composting, they hired an agriculture consultant from Sunrise Ag in Taber to soil sample and develop topography maps to help determine how much compost should be applied at various points on their cropland. The consultant developed maps showing six zones where the compost should be applied to a lesser or greater extent to achieve ideal growing potential. To spread the compost, Perry purchased a Bunning compost spreader with vertical beaters, which he pulls using a John Deere 8430 tractor equipped with hydrostatic drive. Perry recommends a tractor in the 180- to 200-horsepower range. The tractor moves at about 16 kilometres per hour, and the spreader broadcasts the compost over a width of about 40 feet. This results in an application rate of about four tonnes per acre. Increasing or decreasing tractor speed based upon the zone mapping displayed in the cab will increase or decrease the application rate. Larney says he is not surprised by the results witnessed by the Perrys. He says using compost in the lighter, sandier soils under irrigation in southern Alberta delivers “a better bang for your buck” than perhaps it would in the soils where seed potatoes are grown in central Alberta. These soils typically contain more organic material. Given the amount of row crop type production in southern Alberta and because these crops do not return organic matter to the soil, Larney says, “the addition of compost is a very good way of replenishing soil organic matter . . . it’s the quickest way.” He adds that compost also delivers other benefits, such as the addition of micronutrients not present in commercial fertilizer, and also improves the soil’s water holding capacity, making it more resilient to both wind and water erosion. Given how close together both cattle and potato production are in southern Alberta, he says their co-operation is a natural fit. “It kind of makes sense that it (manure) should end up on potato land,” says Larney. He is noticing more feedlot operators moving in the direction of composting the manure in advance versus simply land applying raw manure. “I think a lot of feedlots are now realizing that they should look at composting because you can only rely on your neighbours for so long to take raw manure,” he says. “With the buildup of phosphorus levels in particular close to feedlots, I think the onus is on the feedlot owners to hopefully ensure that these nutrients are spread out over a wider area so that we are not getting high nutrient loading on land close to the feedlot.”
Potato crops require large amounts of most inputs and potato growers seek economical alternatives for what this high-value crop requires.
One day soon, you might be able to give your potato crop an extra boost from beneficial bacteria, thanks to some innovative studies by Ontario researchers.
Adjusting fertility programs by the tiniest increment could net a yield increase. All that might be required is better understanding the soil’s needs or choosing nutrient materials that will work more effectively in particular soil profiles. Three top potato experts share their tips for tweaking fertility that are valid for any potato operation. While most of the recommendations are not new, they may be getting overlooked or they may need to be combined with others in order to get better results.
Just because black cutworms don’t overwinter in Canada doesn’t mean they aren’t a threat to potato crops. The insects spend their winters in the southern United States but travel north on low-level jet streams and, once they cross the border into Canada, they look for a tasty food source. Black cutworm moths prefer some of the weeds that grow in and around fields and, while potatoes are not their favourite food, they will adapt and can wreak havoc on an unmonitored field. A researcher at the University of Minnesota says the cutworms’ new interest in potatoes could be the result of a change in potential host plants. If the moth’s desired weed is being well controlled in a field, it will eat what is available where the wind sets it down. “Black cutworm moths are active flyers,” explains Ian MacRae, the extension entomologist at the university’s Crookston research station. “These insects can travel hundreds of miles in a short period of time aided by an extremely efficient bug highway [a jet stream].” MacRae says if the wind and temperature are conducive and Canadian potato producers are able to get their crop planted in good conditions, there is a chance the moths will arrive about the same time as the plants are emerging. The possibility exists that early arrival could spawn a second generation of the insects later in the season. He says, once landed, reproduction occurs when the moths lay eggs. The emerging larvae will feed on the foliage, but once at the fourth or fifth larval stage they will begin actively eating near the base of the host plant, cutting it off. “The first you might notice a cutworm problem will be plants that are cut at the base or wilting,” MacRae explains. “At night, the worms burrow into the soil and if the tubers are close to the surface, they will burrow into the tuber. They can do more damage to tubers in dry conditions because cracks in the soil will give the cutworms access to what is underneath.” Damage to potato crops early in the season can be a greater problem because the young plants will not recover from being chewed off. There is a possibility that the seed piece might send up another shoot, but the crop will be set back. MacRae suggests early scouting will help identify the problem and allow time for control. There are effective insecticides for control of black cutworm and there are sources of natural mortality, such as predators or parasitic wasps. Birds may be less effective because of the location of the worms and their habit of eating at night. “If you find yourself at a threshold of about 30 per cent of your plants cut, you may want to apply an insecticide,” MacRae says. “If defoliation is this high, it may be that natural mortality sources are not functioning well.” Ensure proper identification of the larvae as black cutworms so the correct product can be chosen for control. Combining regular field scouting with pheromone or light traps to catch the male moths is an effective way to identify the insects. “When scouting, look for stalks at an odd angle or wilting,” MacRae suggests. “Look in the evening when the cutworms come out to feed, and look as much as a half metre away from the plant because they are good walkers. Black cutworms are aptly named because they are a dark caterpillar with a waxy appearance. They will often curl into a C if disturbed. They hang out during the day under clods of soil or in cracks.” MacRae says climate change may be the reason black cutworms are being seen farther north. He doesn’t believe they will begin to overwinter in Ontario or the Prairies, but a warmer climate means they develop faster and may overwinter in more northern states, making the migration north earlier and causing greater problems. “Black cutworms have certainly become a problem in Ontario in the last few years,” MacRae says. “They can be a significant pest issue.” MacRae adds there are some cultural practices that may minimize the impact of black cutworms when they arrive. Planting late can put new, young plants directly on a collision course with the moths and their offspring, so plant early, if possible. He says controlling weeds will reduce the areas where the moths might lay eggs. Growers in the United States use pre-plant tillage to turn over the soil to destroy potential habitat. To date, there is no accurate monitoring system in place for potato crops, according to MacRae, but the cutworms also like corn and the corn growers in some states, such as Iowa, have a black cutworm monitoring network. “The moths seem to appear in Ontario about three weeks after they are seen in the United States,” he says. Ontario growers could tap into the monitoring networks south of the border and use that information as an early warning system, he suggests. Black cutworms could be considered a stealthy yield robber because by the time you begin to notice a problem, it could be a challenge to execute effective control. The best defence is early and frequent field scouting and adopting cultural practices that could minimize the attractiveness of the crop. MacRae believes Canadian potato growers will see black cutworm more often in the coming years, so preparation for and understanding of the pest is a wise approach.
There are other, more sophisticated methods of testing for the presence of late blight spores in growers’ fields, but that’s precisely the reason Eugenia Banks selected a very simple test for her 2016 project.
Post-harvest potato storage expert Todd Forbush of Techmark Inc. in Lansing, Mich., says quality potato storage requires just two things: quality storage facilities and quality potatoes to store.
Researchers are hoping Canadian potato growers will soon be able to use an innovative approach to control wireworms. This method uses just a few grams of insecticide per hectare applied to cereal seeds that are planted along with untreated seed potatoes. It provides very good wireworm control for the whole growing season, with a lower environmental risk than currently available insecticide options. “We’re very excited about this delivery system for controlling wireworms,” says Bob Vernon, a research scientist with Agriculture and Agri-Food Canada (AAFC). He and his research team developed this method by drawing on their in-depth knowledge – gained through their many wireworm control studies – of when and how these soil-dwelling larvae feed. In the spring, about 100 per cent of the wireworm population in a field rises to near the soil surface to feed on plants. Wireworms really like cereals and grasses, but if those aren’t available they’ll eat other crops. In the summer, the wireworms go deeper down to escape hot, dry weather. Then, in late summer, they rise to feed again. As winter arrives, they descend once more. In potato crops, this pattern means wireworms can attack both the mother tubers and daughter tubers. They tunnel into the tubers, reducing marketable yields. “Wireworms find their host material by following carbon dioxide trails emitted by germinating or respiring plants in the soil,” Vernon explains. “For example, as a wheat seed germinates, it produces carbon dioxide. Since wheat is planted in distinct rows, you’ll get very nice carbon dioxide plumes coming from those rows, which will attract wireworms. Once they get to the carbon dioxide source, they’ll feed on the wheat seeds or roots. The same thing happens with potatoes: after planting, the mother tubers eventually start to germinate and produce carbon dioxide and respire, attracting wireworms.” Vernon and his research team realized they might be able to use the wireworm’s food detection system against the pest. “The idea that we had going back about 16 years is that you could put a cereal crop such as wheat in with the potatoes, much like putting a granular insecticide with potatoes at planting. Wheat tends to germinate more rapidly than the mother tubers do, so pretty much all of the wireworms in the field will be attracted to the wheat seed and won’t be as inclined to go to the mother tubers. Now, if you put something lethal on the wheat seed, then you’ll kill most of the wireworms early in the season,” he says. “Because you are drawing the wireworms right to the poison, you can use far less of it than you would, for example, using Thimet [phorate] or Capture [bifenthrin]. With Thimet or Capture, you’re expecting that the wireworms will encounter the insecticide by chance, so you have to use more of the insecticide and it has to be more spread out.” Vernon’s group started working on this companion planting attract-and-kill approach in the early 2000s. They have tested virtually all of the available insecticides to see which ones would work best with this approach. The method requires an insecticide that kills wireworms; if the product just temporarily knocks out or repels wireworms, the pests might return later to attack the daughter tubers. Vernon notes, “At the present time, of the insecticides registered [for wireworm control in potatoes], Thimet will kill and chlorpyrifos [Pyrinex] will kill. Those are registered on potatoes as in-furrow granular or spray applications. They are not really available to be put onto cereal crops.” So to demonstrate the attract-and-kill method, his team has used fipronil. This insecticide, with the product name Regent 4 SC, is registered in the United States for use on potatoes and corn. Vernon’s studies show very low doses of fipronil are quite effective when used with the attract-and-kill method. “For example, we can get the same result as with Thimet 15G but with between about one and five grams of active ingredient fipronil per hectare,” he explains. “To put that in perspective, Thimet is used at 3,250 grams of active ingredient per hectare. So, we’re looking at up to about 3,000 times less active ingredient being put into the soil at planting using the cereal crop attract-and-kill approach with a product like fipronil. And the toxicity of fipronil relative to Thimet is about 100 times less.” This method gives about 80 to 90 per cent wireworm kill early in the growing season. The small remaining population will cause much less damage to the daughter tubers. Another positive aspect of this approach is that the risk of other insects and mammals being exposed to the insecticide is reduced. “The treated cereal seeds are about 15 centimetres below the ground surface, and the insecticide is not broadcast over a larger area,” Vernon says. “And if you start with one gram of active ingredient per hectare, then by the end of the summer only about 0.1 or 0.2 grams per hectare would remain in the soil.” Field experiments show potato yields are very rarely affected by competition with the companion crop. Vernon notes, “We have been able to determine the minimum amount of wheat seed needed to kill wireworms and protect the daughter tubers from blemish damage. We know how much wheat to put in the rows and where to put it so the wheat will not interfere with the growth of the potatoes.” According to Vernon, growers would need to make some fairly simple, low-cost modifications to their existing planting equipment in order to sprinkle the wheat seeds in with their potatoes. The one obstacle to adoption of this method at present is that fipronil is not registered for use with potatoes in Canada. When Vernon started working with fipronil, he was hopeful it would eventually be registered here, but that didn’t happen. However, his team is testing new insecticides every year, and he is “cautiously optimistic” they’ll find a product that can be slotted into the companion planting attract-and-kill approach. Highlights from other wireworm studiesThis attract-and-kill work was funded by various agencies over the years, and the research was recently completed as part of a major project on wireworm control strategies. That project is funded under Growing Forward 2 with the Canadian Horticultural Council, and runs from April 2013 to March 2018. Vernon is the lead investigator on this national project. The collaborating researchers include his AAFC colleagues Christine Noronha, Todd Kabaluk and Ian Scott. The project’s six components are already making substantial progress. One component, which is taking place in British Columbia and Prince Edward Island, is evaluating new insecticides, including products that are not yet registered, to see how well they control wireworms in potatoes. This component (and several of the other components in the project) are looking particularly at effects on the three introduced European wireworm species, which are causing significant problems in Prince Edward Island and British Columbia. Along with validating the effectiveness of Capture, the researchers have also identified other very promising products that could be candidates for registration. Another component involves studies in British Columbia, Alberta and Prince Edward Island to assess the efficacy of various new insecticidal seed treatment products to control wireworms in cereal crops grown in rotation with potatoes. The researchers have found several proprietary products that look very promising. They are also testing sprays for killing click beetles – the adult stage of wireworms. The third component is assessing several ways to use brown mustard for controlling wireworms in Prince Edward Island trials. This research has found that using mustard seed meal as a soil amendment is not practical for field-scale use. However, planting mustard between rows of potatoes shows promise. To improve control strategies, this component also includes a study to learn more about the biology of Agriotes sputator, the invasive European species that is wreaking havoc on Prince Edward Island. In the fourth component, the researchers are developing a biological control method to attract and kill click beetles. They have invented pheromone granules that can be used to attract beetles to an application of Metarhizium spores. This fungus is highly lethal to click beetles, and the trials have achieved up to 95 per cent mortality. The researchers are working on various aspects to develop this method into a cost-effective, practical option for commercial use. The pheromone granules themselves might also have potential as a way to disrupt click beetle mating. The fifth component involves development of a trap for monitoring wireworms, which uses carbon dioxide to attract the pests, and development of a method for monitoring carbon dioxide production. The researchers are testing different ways to improve the trap, and they are monitoring wireworms to predict feeding damage. They have also made an apparatus for measuring carbon dioxide production. The project’s sixth component is the continuation of the national wireworm survey, which started in 2004. Wireworm species information is important because different species can have different responses to control measures. Canada has over 20 wireworm pest species. The species vary from region to region, and multiple species may occur in a single field. AAFC’s Wim van Herk is identifying specimens collected from farm fields across the country and mapping species distribution. Robert Hanner’s lab at the University of Guelph is sequencing the DNA of the specimens to enhance identification.
Sept. 29, 2016 – Second growth is a physiological potato problem induced by soil temperatures of 24 C or above and water stress. These two factors interact to limit the tuber growth rate, causing second growth. Inadequate soil moisture alone does not result in the initiation of second growth. Heat and drought prevailed during the 2016 Ontario growing season, which explains why second growth has been reported in some fields. Potato varieties differ in their susceptibility to second growth. European varieties appear to be more susceptible because they were bred and evaluated in countries where the growing seasons are rarely hot. There are three distinct types of second growth: Tuber chaining: A series of small tubers are produced on a single stolon. Heat sprouts: Sprouts develop from stolons or daughter tubers. The sprouts may emerge from the hills developing into leafy stems. Secondary Tuber: Small tubers form on daughter tubers. The secondary tubers are formed on short sprouts or directly on the tuber surface. This disorder is usually associated with physiologically old potatoes. High temperatures and water stress during the growing season are major factors contributing to the physiological aging of potatoes. Cultural practices that promote uniform growth of plants and tubers throughout the season help minimize second growth. Among them are: ● Do not plant physiologically old seed in cold, dry soil. ● Space seed pieces as uniformly as possible at planting. ● Apply an adequate amount of fertilizers. ● Maintain uniform soil moisture sufficient to meet crop needs (this was easier said than done this past season!).
July 27, 2016, Prince Edward Island – While some areas on P.E.I. got a thorough soaking over the weekend, others are still thirsty for moisture. Water levels are still low in some areas of the province, reports CBC. | READ MORE
Rob Green, a potato farmer in Bedeque, is taking cover crop rotations to a new level. In the past, he grew barley, canola and hay as his rotational crops.
With the help of DNA sequencing, Canadian researchers are linking soil microbial communities to soil health and potato yields. This research is the first stage in eventually developing a tool to diagnose the health of potato fields and to help identify management practices to improve tuber yields and quality.
Brenda Shanahan, Member of Parliament for Châteauguay—Lacolle, on behalf of Minister of Agriculture and Agri Food Lawrence MacAulay, has announced a repayable contribution of $470,000 to help a Quebec company, Logiag Inc., commercialize a laser-based soil analysis system that replaces the more traditional chemical analyses.
Studies have shown adding biochar to soil can improve soil fertility, increase nutrient utilization in plants, improve soil water-holding capacity, increase crop yield and reduce emission of greenhouse gases. However, if you are a potato farmer, your joy may be short-lived. According to research from Aarhus University in Denmark, biochar and potatoes do not go together very well, especially if you’re aiming to save water. Caixia Liu, a PhD student in the university’s department of agroecology, investigated the effects of adding biochar produced from wood on potato growth, yield, nutrient uptake and water utilization when three other factors were also taken into consideration: irrigation methods; phosphorous fertilization; and inoculation with a certain class of beneficial fungi. Liu’s aim was to investigate the interactions between biochar and the fungi on the growth of potatoes. Biochar and AM-fungi do not go well togetherPotatoes are rather sensitive to drought and phosphorous deficiency because of their relatively small root system. It would be easy to merely irrigate and fertilize in plentiful amounts, but since both phosphorous and water are limited resources, it is important to use them optimally. Earlier studies at Aarhus University have shown water can be saved by irrigating alternately on each side of the potato ridge and letting the other side remain dry – the so-called alternating partial root zone drying irrigation method. It is also possible to save phosphorous. In the course of her PhD studies, Liu found inoculation of potatoes with the beneficial arbuscular mycorrhizal fungi (AM fungi) can improve potatoes' utilization of phosphorous, make utilization of water more efficient, and increase potato yield in crops that are stressed due to drought or phosphorous deficiency. The question was what would happen when biochar and inoculation with AM fungi are combined. Would there be a double win? The answer was no. Liu conducted a series of studies with various combinations of irrigation (either full irrigation or alternating partial root zone dehydration), phosphorous fertilization (none or 0.11 milligrams of phosphorus per gram of soil, or mg P/g soil), inoculation with AM fungi (inoculation or no inoculation) and addition of biochar (addition or no addition). Biochar inhibited the growth of potatoesIf the crop is irrigated fully, the soil is given no phosphorous at all, and the potatoes are not inoculated with AM fungi, then addition of biochar can increase potato yield. This was the only case in which this was true; in all other instances, addition of biochar to the soil had the opposite effect. The negative effect on potato growth was especially pronounced when phosphorous was added, alternating partial root zone drying irrigation was used, and the potatoes were inoculated with AM fungi. Addition of biochar inhibited the growth and vigour of young potato plants. Some of the young potato plants even died. “I would recommend that the farmer refrains from adding biochar produced on the basis of wood to an AM system, where the soil has been fertilized with phosphorous or if the soil is prone to drought. Biochar remains in the soil for a long time so there is no going back,” Liu said, in a press release.
Due to hot, dry conditions, farmers in Norfolk County, Ont., have used irrigation in an effort to save the crop. But with less than half an inch of rain in eight weeks, irrigation has been no use, and the local yield could be down by 50 per cent. | READ MORE
Bernie Zebarth is leading a four-year project that will study large-scale compost application on potato fields in New Brunswick, and the resulting effects on yield and soil health. Photo courtesy of Bernie Zebarth. In 2013, eastern Canadian potato growers were concerned: they were not seeing the yield increases experienced by growers throughout the rest of North America. Manitoba has seen an average yield increase of 4.4 hundredweight per acre (cwt/acre) each year. By contrast, New Brunswick sits at an average yield increase of 1.4 cwt/acre, and P.E.I. at 1.1 cwt/acre. One possible culprit for stagnating yields is declining soil health in the eastern provinces. “With sloping land and intensive tillage, you have a lot of issues with soil erosion,” says Bernie Zebarth, a researcher with Agriculture and Agri-Food Canada (AAFC) based in Fredericton. “We also have a short rotation for potato, so we’re not getting much organic matter back to the soil. Our concern is that the declining soil health is limiting yield.” New Brunswick’s processing potato industry is crucial; the province exports most of its product for french fries, and without increasing productivity it loses competitive advantage. Industry asked for help, and in 2014, Zebarth took the science lead on a four-year industry-led project that will study large-scale application of compost on fields across New Brunswick, and the resulting effects on potato yield and soil health. Potatoes New Brunswick is leading the project, with McCain Foods Canada heading up the on-farm trials. The project will also study a variety of compost products in experimental plots at the AAFC Fredericton Research and Development Centre. “We want to see the implications of adding compost to the soil, in terms of yield and tuber quality,” Zebarth says. “How much of a yield difference is there? Will it be cost-effective? How will it fit into growers’ practices? What soil quality parameters does it improve? We want to be able to know which index is the best to use to assess soil health. Can we suppress soil-borne diseases? Will compost fit into New Brunswick potato production?” The study is part of a larger three-year study that aims to identify areas in New Brunswick, Manitoba and P.E.I. potato fields that have a yield limitation, identify the source of the limitation, and identify mitigation practices to overcome that limitation. Zebarth says his team is hoping to assess whether adding compost to the soil will help accomplish in a short time what improved rotations might accomplish over a much longer period. “Because we don’t irrigate, I’m thinking that when it comes to soil health and soil quality, what we’re really after is improvement of the soil’s physical properties, such as water holding capacity and tilth. Any field with a problem with physical properties could benefit from compost.” The field-scale trials led by McCain in commercial fields for the project involve paired treatment strips in growers’ fields – one treated with compost, one untreated. They are evaluating yield and tuber quality, as well as soil water content and other physical properties of the soil. Meanwhile, with help from Dalhousie masters student Carolyn Wilson, Zebarth is analyzing five different compost products, assessing their impact on tuber yield and quality, soil quality and on soil-borne diseases like common scab. The compost being used in the field trials is a wood shaving litter with poultry droppings, which reuses wastes from agriculture and forestry to build soil organic matter. The other composts being analyzed at the Fredericton Research and Development Centre include a forestry residue compost, a source-separated organics compost, a poultry manure-bark compost and a marine-based compost. The third component of the study is based in the lab, where, along with AAFC researcher Claudia Goyer, Zebarth is using next-generation sequencing to characterize the microbial life in soil samples. It’s too soon to talk about results. Zebarth is optimistic that compost can help improve soils over time, but he cautions that compost is a “probabilistic” solution. “We’re thinking about compost almost like you look at a capital investment,” he says. “It’s not like a nutrient application, but an infrastructure improvement, where you get payback over the next five to 10 years.” In some fields, growers may only need to apply compost to certain parts of the field that have soil physical problems. As cost has traditionally been a prohibiting factor for growers hoping to use compost, Zebarth’s team is hoping the study might help them identify a particular compost product that can be scaled up to reduce the costs. There’s no silver bullet when it comes to soil health, but compost is what Zebarth calls “one tool in the tool box” for improving the soil – and ramping up productivity – over time.
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AAFC Charlottetown Research Centre Open House and TourFri Aug 04, 2017
Potato Research DayWed Aug 09, 2017
Ontario Potato Field DayThu Aug 17, 2017
Summit on Canadian Soil HealthTue Aug 22, 2017