Production

May 17, 2012, Ottawa, Ont – The Canadian Horticultural Council (CHC) and Canadian Produce Marketing Association (CPMA) will integrate the CanadaGAP (On-Farm Food Safety) Program and the CPMA Repacking and Wholesale Food Safety Program (RWFSP).

Both the CHC and CPMA boards of directors approved the integration initiative during their respective annual meetings earlier this year.

Integrating the two programs will result in some key benefits for the Canadian fruit and vegetable industry, including:

  • adopting an industry-wide food safety system that meets customer requirements
  • ensuring consistent and complementary food safety standards from producers and packers to wholesalers and re-packers
  • lessening the confusion around overlapping programs or requirements
  • meeting the needs of companies that pack and re-pack product
  • maintaining strong linkages between the various levels of the value chain
  • competing more effectively with other internationally-recognized programs whose scope reaches further along the value chain
  • integrating audits, audit checklists, auditor training, government technical reviews and international benchmarking processes (saving time and money)

A formal study was undertaken in 2010 to examine the feasibility of the joint venture. The study concluded this was a feasible initiative. The two programs will be integrated under an autonomous corporate entity that will function independently of both CHC and CPMA.

Work on this initiative will continue through 2012 and 2013, with funding assistance from Agriculture and Agri-Food Canada through the Canadian Integrated Food Safety Initiative under Growing Forward. The integrated program could be available by 2013 and 2014.

Published in Federal

May 17, 2012, Guelph, Ont – Syngenta Canada Inc. recently announced the registration of Quadris Top, a pre-mix fungicide for the control of a broad spectrum of diseases in both potato and vegetable crops.

Quadris Top contains two active ingredients: azoxystrobin (a Group 11 strobilurin fungicide) and difenoconazole (a Group 3 triazole fungicide) with translaminar and xylem-systemic properties for preventative control of target pests.

“Quadris Top is an exciting evolution of an already trusted and effective fungicide,” stated Eric Phillips, asset lead for fungicides and insecticides for Syngenta Canada Inc. “With a dual mode of action, Quadris Top provides the disease control growers have come to appreciate with Quadris, along with the addition of the active ingredient difenoconazole for enhanced performance.”

Specifically, in potatoes, Quadris Top protects against early blight (Alternaria solani). Other key diseases controlled in potatoes include black dot (Colletotrichum coccodes), brown spot (Alternaria alternata) and Botrytis leaf blight (Botrytis spp.).

In vegetable crops, Quadris Top provides protection against leaf blight and Cercospora leaf spot in carrots; purple blotch, leaf blotch, Stemphyllium leaf blight, Botrytis leaf blight and downy mildew in bulb vegetables; Ascochyta blight and Anthracnose in dried shelled peas and beans; Mycosphaerella blight in field peas; plus, several other diseases in a wide variety of horticultural crops.

Quadris Top can be applied by ground or air (for potatoes only). It is a disease resistance management tool, and should be used in a fungicide spray program alternating with other modes of action.

Published in Diseases

May 16, 2012, Guelph, ON - Farm & Food Care held its inaugural board meeting and elected its first executive at a meeting in Guelph on May 11th.

John Maaskant will serve as the first chairman of Farm & Food Care.  John is the Chicken Farmers of Ontario representative and the past chair of the Ontario Farm Animal Council. He and his family farm near Clinton, Ontario.

“We are excited about the future of this organization as we build on our strong foundation and look forward to the future,” said Maaskant.  “Farm & Food Care’s work will benefit the whole agri-food sector by cultivating awareness and building appreciation for food and farming.”

Larry Lynn, representing Grain Farmers of Ontario, has been chosen as the organization’s Vice Chair.  Rounding out the executive is Treasurer Joe Hickson representing the Seed Growers’ Association and Executive member at large Heather Copland representing Grober Inc.

All four executive members formerly sat on either the board of directors of the Ontario Farm Animal Council or AGCare - Agricultural Groups Concerned about Resources and the Environment. The organizations amalgamated to become Farm & Food Care Ontario in January which has been operating with an interim board of directors until this meeting.

Other directors include:

  • Lianne Appleby - Hendrix Genetics
  • Marinus Bakker – Ontario Bean Producers’ Marketing Board
  • Bruce Christie – Nutreco Canada Inc.
  • Beth Clark – Ontario Pork
  • Jim Poel – Ontario Processing Vegetable Growers’ Association
  • Gerald Rollins – Ontario Cattlemen’s Association
  • Ed Scharringa – Christian Farmers’ Federation of Ontario
  • Murray Sherk – Dairy Farmers of Ontario

At the meeting, the board focused on setting direction for the coming year, approving a business plan and financial statements. Board members will go through a strategic planning exercise in June.

About Farm & Food Care

Farm & Food Care Ontario is the first coalition of its type in Canada, bringing together tens of thousands of farmers and related businesses with a mandate to provide credible information on food and farming in Ontario. To learn more about Farm & Food Care Ontario or to support the organization’s efforts, visit www.farmfoodcare.org.

Published in Provinces

May 14, 2012, Dorchester, Ont – The Pest Management Regulatory Agency (PMRA) has granted a User Requested Minor Use Label Expansion (URMULE) for Ranman 400SC fungicide. Suppression of white rust on spinach has been added to the product label.                                                                    

White rust is a common disease of spinach that has been on the rise in some parts of Canada over the last few years. Ranman fungicide is a Group 21 product with the active ingredient cyazofamid and is also registered for use on carrots, cucurbits and potatoes.

“The addition of white rust to the Ranman product label is an important step to providing spinach growers with the tools needed to effectively manage production of their crop,” says Janet Porchak, national marketing manager with UAP Canada Inc., distributors and retailers of Ranman fungicide in Canada.

Porchak notes that the work to add white rust to the product label dates back a few years and is the result of collaboration between the Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA), growers and extension personnel, as part of the ministry’s minor use program.

Ranman fungicide can be used at a rate of 0.15 to 0.20 litres per hectare in 300-500 litres of water per hectare.  

David Strilchuk, Canada country manager with FMC Corporation, the marketers of Ranman in Canada, says the product should be applied on a seven-day schedule starting when conditions are conducive to disease development or when disease is first seen.

“Ranman can be applied up to five times per year and has a one-day pre-harvest interval requirement.”

Strilchuk says Ranman fungicide should also be used as part of an Integrated Pest Management program and in rotation with other disease management products as part of an effective resistance management strategy.

Published in Diseases

May 11, 2012 – Ontario is working with producers to assess the damage, determine the implications and develop strategies to help farmers cope.

Minister of Agriculture, Food and Rural Affairs, Ted McMeekin, toured a Beamsville orchard recently to see firsthand the weather damage affecting Ontario’s apple and tender fruit crops.

"I know how much this loss means to the farmers involved, and not just in economic terms,” said Ted McMeekin, Minister of Agriculture, Food and Rural Affairs. “I will continue to closely monitor the situation as we work to assess the damage and develop strategies that will best support the industry.

Early estimates suggest widespread damage to the Ontario apple crop as a result of frost hitting trees already in blossom. Other crops that are reporting significant damage include pears, cherries, peaches, nectarines, apricots and plums. Apple orchards in Georgian Bay and Southwestern Ontario are expected to suffer the greatest damage.

The full extent of the province-wide impact will be known in coming weeks. Ontario offers a number of business support programs available to producers to help offset any losses.

Supporting our farmers and agricultural industry is part of the Ontario government’s plan to create jobs, grow the economy and provide Ontario families with healthy, local food.

Published in Insects

May 11, 2012, Vineland, Ont – Ontario’s apple and tender fruit growers are appreciative of the concern and support they’re receiving from consumers, media and the provincial government as they assess unprecedented weather damage to this year’s crops.

Ted McMeekin, Ontario Minister of Agriculture, Food and Rural Affairs, met with industry leaders today while touring a Beamsville-area orchard to get a first-hand look at the widespread damage that has affected farmers across the province.

“We’d like to thank the Minister for meeting with us today and personally viewing the extent of some of the damage,” says apple farmer Brian Gilroy, chair of the Ontario Apple Growers. “We also appreciate the outpouring of concern and support from consumers and media. The spin-off effects of this crisis will be felt far beyond the farm gate.”

The summer-like weather earlier this year brought blossoms early, leaving them vulnerable to recent frost and cold temperatures. Frost damage results in some trees not bearing any fruit, and if they do, at much lower yields than normal. Some fruit will have visible damage.

Although farmers are most directly affected, impacts will also be felt by farm workers, marketers, suppliers, retailers and ultimately, consumers. Initial assessments indicate up to 80 per cent of the province’s apple crop has been affected, as well as an estimated 30 to 40 per cent loss in peach production and a virtually complete devastation of the cherry and plum crops.

 “We won’t know the full extent of losses for another few weeks, but we’ve never seen damage this widespread,” says Phil Tregunno, chair of the Ontario Tender Fruit Producers’ Marketing Board, which represents growers of peaches, nectarines, pears, plums, seedless coronation grapes and chilled and pitted cherries. “There are some government programs available to assist farmers, but there are gaps and we will need the government to work with us to ensure support for affected growers.”

Published in Fruit

May 8, 2012, Vancouver, BC – The British Columbia Blueberry Council is reporting that this year’s blueberry crop is looking good after a relatively mild winter, and little weather damage.

While it is too early to estimate the size of the harvest, signs point to picking starting in the middle of July.

“Our blueberry plants are beginning to bloom and bees should be heading out into the fields soon,” said Debbie Etsell, executive director of the B.C. Blueberry Council. “Weather has been about 1 degree Celsius cooler than normal which has put us slightly behind, but we shouldn’t be as late as last year.”

Last year’s B.C. blueberry harvest started three weeks later than usual, around July 18, but produced a record number of berries, coming in at 40 million kilograms.

The British Columbia Blueberry Council represents more than 800 blueberry growers with plantings of high bush blueberries around 8,100 hectares that produce around 40 million kilograms of blueberries annually.

Published in Fruit

May 4, 2012, Guelph, Ont – Engage Agro Corp. recently announced that Health Canada’s Pest Management Regulatory Agency has approved Torrent fungicide for use in Canada.

The product is approved for the control of late blight in potatoes, downey mildew in cucurbits and cavity spot in carrots. Additional crops and pests may be added in the future.

Torrent is active in all stages of the disease life cycle. It provides protection against diseases caused by oomycetes, especially infection by pathogens of the genera of Phytophthora, Pythium and Pseudoperonspora. The product is a contact fungicide and belongs to the FRAC Group 21.

“Torrent is a particularly important to growers because it offers them another weapon to combat the increasing threat of pest resistance,” said Engage Agro’s product manager Bob Hamilton. “We look forward to working with ISK Biosciences to bring Torrent to Canada and expand the Torrent label for additional uses in the future.”

The active ingredient in Torrent is Cyazofamid, which inhibits mitochondrial respiration. While Torrent is not systemic, it does provide some translaminar movement though the plant tissue. It is available in a suspension concentrate formula.

Published in Diseases

May 4, 2012, Vineland Ont – Ontarians can expect fewer locally grown apples in stores this fall and those that will be on the shelves will likely be more expensive.

That’s due to spring frost that has caused widespread damage to Ontario’s apple orchards. The summer-like weather in March brought apple bloom development one month early, leaving them vulnerable to the recent sub-zero temperatures.

“This is widespread damage and we’re seeing some apple farmers with 100 per cent loss in their orchards so they won’t have a crop at all this year,” says Brian Gilroy, an apple grower from the Georgian Bay area and chair of the Ontario Apple Growers. “Other farmers have varying degrees of damage, depending on their orchard location and region, but every apple grower is affected.”

Trees may look normal but the frost has damaged the blossoms so they will not bear any fruit, and if they do, farmers will see fewer apples per tree.  Some fruit will have visible damage, including frost scaring and ridging, where apples develop ridges similar to those on pumpkins.

For consumers, this translates into fewer locally grown apples in the store, which could also result in higher apple prices. Apple growers will experience reduced yields and decreased income, yet even those farmers who have lost their entire crop will still be faced with significant costs to maintain orchards.

“For farmers who do have apples, they won’t have the quantity to sell that they normally would so we’ll definitely see fewer Ontario apples in the stores this fall,” says Gilroy. “Even if there’s no crop, you still have to maintain the orchards for future crops. You can’t just walk away.  It’s going to be a tough year for apple farmers.”

Published in Research

May 4, 2012 – Can organic agriculture feed the world?

Although organic techniques may not be able to do the job alone, they do have an important role to play in feeding a growing global population while minimizing environmental damage, according to researchers at McGill University and the University of Minnesota.

A new study published in Nature concludes that crop yields from organic farming are generally lower than from conventional agriculture. That is particularly true for cereals, which are staples of the human diet – yet the yield gap is much less significant for certain crops, and under certain growing conditions, according to the researchers.

The study, which represents a comprehensive analysis of the current scientific literature on organic-to-conventional yield comparisons, aims to shed light on the heated debate over organic versus conventional farming. Some people point to conventional agriculture as a big environmental threat that undercuts biodiversity and water resources, while releasing greenhouse gases. Others argue that large-scale organic farming would take up more land and make food unaffordable for most of the world’s poor and hungry.

“To achieve sustainable food security we will likely need many different techniques – including organic, conventional, and possible hybrid systems – to produce more food at affordable prices, ensure livelihoods to farmers, and reduce the environmental costs of agriculture,” the researchers conclude.

Overall, organic yields are 25 per cent lower than conventional, the study finds. The difference varies widely across crop types and species, however. Yields of legumes and perennials (such as soybeans and fruits), for example, are much closer to those of conventional crops, according to the study, conducted by doctoral student Verena Seufert and geography professor Dr. Navin Ramankutty of McGill University and Dr. Jonathan Foley of the University of Minnesota’s Institute on the Environment.

What’s more, when best management practices are used for organic crops, overall yields are just 13 per cent lower than conventional levels.

“These results suggest that today’s organic systems may nearly rival conventional yields in some cases – with particular crop types, growing conditions and management practices – but often they do not,” the researchers write.

Improvements in organic management techniques, or adoption of organic agriculture under environmental conditions where it performs best, may help close the yield gap, they indicate.

“Our study indicates that organically fertilized systems might require higher nitrogen inputs to achieve high yields as organic nitrogen is less readily available to crops. In some cases, organic farmers may therefore benefit by making limited use of chemical fertilizers instead of relying only on manure to supply nitrogen to their crops,” Seufert says. “At the same time, conventional agriculture can learn from successful organic systems and implement practices that have shown environmental benefits, such as increased crop diversity and use of crop residues.”

Yields are only part of a set of economic, social and environmental factors that should be considered when gauging the benefits of different farming systems, the researchers note. “Maybe people are asking the wrong question,” Dr. Ramankutty says. “Instead of asking if food is organically grown, maybe we should be asking if it’s sustainably grown.”

The results point to a need to get beyond the black-and-white, ideological debates that often pit advocates of organic and local foods against proponents of conventional agriculture, Dr. Foley adds. “By combining organic and conventional practices in a way that maximizes food production and social good while minimizing adverse environmental impact, we can create a truly sustainable food system.”

Published in Research

May 2, 2012, Ithaca, NY – With its two newest raspberry releases, Cornell University is going gold and crimson. Double Gold and Crimson Night offer small-scale growers showy, flavourful raspberries on vigorous, disease resistant plants.

“Both varieties have attracted a lot of interest from small-scale growers because they are looking for varieties with intense flavor and a different look from the supermarket varieties,” said Courtney Weber, Cornell small fruits breeder and associate professor of horticulture. “If consumers get a taste of these, they will buy them.”

Double Gold produces a deeply blushed, golden champagne-coloured fruit with a distinctive conical shape, earning the double in its name for its two harvests per season. The first year of planting, the initial crop is produced in the fall on the tips of that year’s canes, and a second crop is produced farther down the same canes the following summer.

According to Weber, none of the golden raspberries already on the market combine excellent flavour, peachy blush colour, a conical shape and the ability to bear two crops per season.

“I have been told by sellers at farmers markets that having several colours on your display is a good way to draw in customers and distinguish you from other sellers,” said Weber. “I’m hoping Double Gold will fit that niche.”

In Weber’s taste tests, the flavour of Double Gold has been a favourite. The release is targeted to you-pick growers and farm stands because the fruit is too delicate for long-distance shipping. Although the fruit is tender, the plants that bear them are tough.

“Over eight years of testing it has been consistently vigorous and disease resistant,” said Weber. “Specifically, we have observed it to be resistant to Phytophthora root rot as well as most of the common leaf diseases.”

Crimson Night caught Weber’s eye for its heavy fall crop and dark, shiny fruit. Grown in a commercial high-tunnel system that offers protection from the elements, it is vigorous and productive. Grown outdoors without protection, Crimson Night is more compact.

“The berries are medium large with excellent flavour,” said Weber. “Although the colour is considered too dark for wholesale markets, the shiny, conical fruit are very attractive in a container at a farm stand.

According to Jessica Lyga, plant varieties and germplasm licensing associate for the Cornell Center for Technology Enterprise and Commercialization, both varieties have been licensed to North American Plants LLC, a propagator that sells to nurseries and growers across the United States. Small quantities will be available late this summer, and North American Plants expects to have enough plants to meet the anticipated demand of each variety by the spring of 2013. Plant patents will be filed later this year.

Double Gold and Crimson Night are the fourth and fifth new berry varieties introduced by Weber in the past year. Recent releases include Purple Wonder, the darkest strawberry variety available; the Herriot strawberry, a high-yielding midseason variety; and the Crimson Giant raspberry, suitable for high tunnel cropping systems with a November harvest. Weber hopes to maintain a steady pace with selections this summer.

“For 2012 there will be approximately 20,000 raspberry seedlings under evaluation, and we will plant about 7,500 more,” he said. “We’ll also be adding 2,500 more strawberries to the 2,000 already under evaluation.”

Published in Research

Despite their reputation, the vast majority of nematodes are not only considered beneficial but also as organisms vital for maintaining soil and plant health, says Becky Hughes, University of Guelph, New Liskeard, Ont. The microscopic worm-like organism has thousands of classifications but a few hundred species are considered plant parasites.


“When you think of a nematode you tend to think of the ones that live in the soil such as the root knot and root lesion nematode. The one of concern for garlic growers is the bulb and stem nematode that also eats leaves and lives within the bulb,” she said. The persistent pest, identified as Ditylenchus dispsaci, was identified in California in the 1960s and in Ontario some 10 years ago. This pest threat was initially thought limited but it has caused significant damage in recent years and some growers have lost whole crops. Intensive research into how widespread this pest is in Ontario began about two years ago. This particular nematode lives in the plant and feeds on the leaves, stem and bulb so it can be easily spread with the seed or any other part of the garlic plant or dried plant debris. It can also survive for years in the dried trash stuck to dirty tractors, equipment and storage boxes. When access to soil is available, the pest can return to the soil and live for many years without a host. Heavy clay soils give it greater longevity compared to sandy loam. There are also a number of strains or races of this pest. Looking at the signs and symptoms, Hughes says it causes stunting and yellowing plants that die prematurely throughout the season. If the plant was infested at planting time, it will likely appear as a dwarf with a thick distorted stem and small leaves. The bulbs can be without symptoms, however, the root plate can rot separating the bulb from the root system. This condition causes the bulb to rot, and the advent of secondary infections such as fusarium, hampers pest identification. Plants with this condition are easily identified by their yellowed, dwarf appearance and when pulled, easily break off from the base


Looking at the life cycle, Hughes says the pest actually burrows from the leaf down to the bulb and root plate where it develops and feeds. As the bulb rots and the pest reproduces, juvenile nematode offspring move into the soil and swim to a new place to live. These juveniles swim well not only in wet soils but also in the film of water on plant tissue and the soil surface. “It really only takes one infected plant to infest a field,” she said


“To make things complicated, bulb and stem nematode has a wide range of hosts. It will grow in corn, bean, rye, onion, peas, corn and strawberry crops. It also has a range of 300 to 500 species. To complicate things more there are about 30 known races and likely more that attack a specific host or specific group of hosts. We have found that the race that attacks onion and garlic tends to stick to the onion family and does not attack field crops like canola or alfalfa. And there is one race that attacks garlic and strawberries that is totally unrelated. We still don’t know all of the races that are out there,” she said


In 2010, working with the Garlic Growers Association of Ontario (GGAO), they created a study to track the extent of infestation across the province and to identify the prominent races. Nothing similar has been done since 196
In this study, researchers collected 10 garlic bulbs from growers across Ontario. Growers in turn, completed a questionnaire on seed sourcing and cropping practices.


“When we started collecting samples some of the garlic looked too nice but that changed later in the season,” she noted


Infected bulbs were sent to the lab to identify the race of nematode. In a misting chamber, the nematodes will actually crawl out of a dug garlic bulb after about 24 hours, and the technicians can then identify and count their numbers in solution, she said


From their survey results, the research team collected 123 samples from 79 farms in 33 counties. Of these samples, 59 per cent were of the Music variety, and 73 per cent of all the samples had bulb and stem nematode


Of note, Hughes said there tended to be a higher infestation rate in south-central Ontario where the highest number of samples were collected. She also noted that 18 per cent of the Music variety had no nematode infection.


“They were clean,” she said.


From their recommendations, “a good crop starts with clean seed, and it’s a good idea to get a sample of your seed tested by the University of Guelph before you plant it,” she said. For cleaner fields, Hughes said Cutlass oriental mustard does a good job of nematode suppression. She also suggested a minimum four-year crop rotation with no Allium crops until the race of the nematode can be identified. “We suspect it’s all the same race of bulb and stem nematode but we’re not sure at this time,” she said. Keep infested seed separate from clean seed both in the field and in the storage area, and always plant the clean seed on the higher ground. Thoroughly clean and disinfect your equipment and the storage area when finished. Some growers might consider using the hot-water seed treatment.

Hughes said she is no expert in this treatment so could make no recommendations, however, directions are available on the Internet and some careful growers have had good success. “The bottom line for all growers in the industry is to always consider growing clean seed,” she said. Hughes said the basics for the virus-free seed being developed in their laboratory starts at micro-propagation with clones established in culture by tissue or bulbils. These are tested for pathogens, and if clean, plantlets are established and multiplied


For stock plant maintenance, the clones of these stock plants are grown during the winter in the greenhouse. For production, plantlets are planted in a screened greenhouse and single clove bulbs are harvested in August, she said
Based on the results of their garlic study with the growers, and their laboratory work to test the efficacy of virus-free seed, Hughes says they hope to assist growers in the management of their crops with the proper identification of the problem.

Published in Research

Chemical additives that help agricultural pesticides adhere to their targets during spraying can lead to formation of smaller “satellite” droplets that cause those pesticides to drift into unwanted areas, Purdue University researchers have found.


Carlos Corvalan, an associate professor of food science, said understanding how the additives work together means they could be designed to decrease the health, environmental and property damage risks caused by drift. Corvalan; Osvaldo Campanella, a Purdue professor of agricultural and biological engineering; and Paul E. Sojka, a Purdue professor of mechanical engineering, published their results in a February issue of the journal Chemical Engineering Science.


“When we spray liquids, we have what we call main drops, which are drops of the desired size, and we can also have smaller satellite drops. The smaller drops move easily by wind and travel long distances,” Corvalan said. “Now that we know better how additives influence the formation of satellite droplets, we can control their formation.”


When liquids are sprayed, they start in a stream and eventually form drops. As the liquids move farther in the air, drops connected by a thin filament start to pull apart. That filament eventually detaches and becomes part of the drops that were forming on either side of it.


Satellite droplets form in the middle of filaments of pesticides containing surfactants and polymeric additives, which help the pesticides wet and adhere to plant surfaces. The surfactants reduce surface tension and force round drops to flatten, helping them cover more surface area on a sprayed plant’s leaves. The polymeric additives reduce viscosity – liquid resistance – making the pesticide flow easier. Polymeric additives also keep the drops from bouncing off plant surfaces.


“Each additive is designed to improve the characteristics of the main drops,” Corvalan said. “But there is a side effect.”


When both additives are present in a pesticide, the surfactant pushes more liquid toward the filament. The reduced viscosity allows liquid to flow more easily in that direction, resulting in a well-defined satellite drop forming in the filament.


“When you put both additives together, there is a synergistic effect. The force induced by the surfactant that was opposed by viscosity is no longer so strongly opposed, and this combined effect can result in the formation of satellite droplets,” Corvalan said.


Drifting of agricultural pesticides not only increases waste and cost for farmers but also can cause health, environmental and property damage, according to the U.S. Environmental Protection Agency.


The results show that carefully modulating the strength, concentration or ratio of surfactants to polymer additives can mitigate or eliminate the formation of unwanted satellite droplets.


Corvalan is now transferring the results obtained from agricultural research into food processing and rocket propulsion work. He said drop size uniformity is as important for fuels sprayed into rocket combustion chambers as for the production of food emulsions.

Published in Research

As many cole crop growers know, clubroot can be very destructive to the brassica family, says Dr. Mary Ruth McDonald, professor of plant agriculture at the University of Guelph, Guelph, Ont. This large family includes such familiar members as rutabaga, kohlrabi, cabbage, cauliflower, Brussels sprouts, mustard, bok choy and even rapeseed.


Clubroot is not caused by a fungus but rather by protozoa, which helps explain why the fungicides designed for other soil-borne diseases do not work well for clubroot. The resting spores can lie dormant in the fields for a very long time and awaken when cole crops are planted.


“It tends to thrive when you have a warm, wet climate and acidic soil,” she says.


Once awakened from its dormant phase, the disease soon produces zoospores that swim through water-soaked soils to find and infect the plant’s initial fine root hairs, Dr. McDonald explains. There they rest and produce a fresh flush of new zoospores. This fresh flush later attacks the primary root of the main plant where they nest and multiply again.

The protozoa cut off and divert the root energy and nutrients to themselves, leaving the plant with a clubroot. This causes stunting or death for infected plants.


For many years, crop advisors have recommended avoiding infested, wet fields and doing a long crop rotation every five to seven years. Another tactic is to increase the soil pH to 7.2 or above. These measures work for many growers but not all, she says.


In a controlled laboratory environment, University of Guelph graduate student Hema Kasinathan has run trials with canola, an immediate brassica relative of rapeseed, through the paces of temperature, pH and soil moisture.


In this controlled environment, research was conducted on a soil pH range of 5 to 8, with air temperatures of 10 to 30 C. It was soon discovered that plants at 10 and 30 C did not fare well and were dropped from the study. The remaining canola trials were assessed six weeks after inoculation when there was plenty of disease available.


As in previous studies, the researchers found that 25 C was optimal for clubroot development, and even at the high pH level of 8, the plants still suffered a 40 to 50 per cent infection rate. The canola plants grown in the same pH soil, but at 20 C, received a 20 to 30 per cent incidence of clubroot.


“These results demonstrate that while raising the pH helps, it will never get you zero infections, if other conditions favour disease development,” she says.


Overall, researchers found that raising the pH, with cool air temperatures of 10 to 15 C, helped lessen the incidence of injury. Cool soils, however, were ideal in delaying the onset of clubroot, so if possible plant the crop early, says Dr. McDonald.


Of the clubroot fungicide trials, Dr. McDonald says the bio-fungicides worked best in 2009 but not so well in 2010.


“The results have been variableand nothing is really consistent,” she says. “That might be because we needed higher rates or more water.”


More fungicide research needs to be done.


As for varieties resistant to clubroot, Guelph researchers have been appraising four resistant cabbage cultivars from Syngenta. Other resistant varieties available include bok choy, Brussels sprouts and broccoli.


The standard varieties are highly susceptible to clubroot but resistant strains are on the market and they perform well. Tolerance in 2011 fell for the resistant broccoli hybrids planted in the same field two years in a row. It displayed some clubroot but it still yielded four times more than the susceptible variety in the check plot.


The resistance bred into the new plant varieties is most impressive but will it stand the test of time? “In Europe, they have a resistant line of canola but over the years they have seen this broken down,” says Dr. McDonald.


Each year, a number of resistant cultivars developed from seed companies become available.


“I know the seed prices are expensive,” she says. “If you don’t have a clubroot problem and traditionally have little disease pressure, then there is no advantage. But if you do, the new resistant varieties are well worth the cost.”


The bottom line is to maintain good management practices and use fungicides wisely and effectively regardless of what you plant. As well, go back to the original recommendations of planting in well-drained fields, and increase your pH to 7.2 or higher as it will reduce your disease pressure. For brassicas such as bok choy, try to plant early in cool soil. For all crops, always use a long-term rotation, even with the resistant varieties that should be rotated wisely.


In the future, Dr. McDonald says researchers are looking at the resistant cultivars as well as the mechanisms of resistance to determine what genes are involved and which ones can be identified. The results from the 2011 research is available on the OMAFRA website.

For more information, visit www.plant.uoguelph.ca/index.html.

Published in Research

Late blight is an important topic that scares us all, and its devastation of tomato crops can be widespread, says Dr. Tom Zitter, a plant pathologist with Cornell University based in Ithaca, N.Y.


The epidemic that occurred in U.S. tomato crops during 2009 was unique because it began so early in the season and occurred so evenly over such a large geographical area, something that never happened before. Another feature of the epidemic was that a new genotype of the pathogen was responsible – US-22 – and was capable of infecting both tomatoes and potatoes. To be sure, the principal genotype affecting potato at that time – US-8 – was also present in New York State, but affected only limited potato acreage. Genotype US-8 is limited to potato and most likely originated from infected tubers used for seed for the 2009 crop.


So why is late blight important? asks Dr. Zitter. When he and Dr. Bill Fry began their 2009 study, the disease had likely got its start in Florida in May 2008, then started working its way north.


Dr. Zitter’s first encounter with this strain was on June 24, 2009, when a colleague brought him some samples to identify the pathogen on the leaves. The plants came from the garden section of a local big-box store.


That same afternoon, Dr. Zitter visited the four big-box stores in Ithaca and found their tomato plants were infected with late blight, but no infection was found at five local garden centres that had grown their own plants or had received them from other suppliers. He advised some customers against buying them at the big-box stores and also spoke with the store managers, who said they got the plants on consignment. They said they would speak to the supplier and ensure the plants were removed by Saturday.


Dr. Zitter returned to the same stores the next Saturday and the plants at that provider were gone. He felt reassured, but only briefly. When the other stores around the state realized they had a problem on their hands, some centres put their plants on sale for half price. “By that time we already knew we had an epidemic; the genie was out of the bottle. By the middle of August of that same year the disease spread was statewide,” he says.


Potatoes usually get late blight first but in 2009 it was the tomatoes, and the primary source for spreading the disease was the unknowing home gardener. The onset was very early in the season and the environmental conditions were highly favourable for late blight from New York up into Maine.


Commercial growers had to go on a crash course of spraying every four to five days, as did organic growers, who were actually able to control it by removing infected plants and using regular sprays of copper, he says. Homeowners could not respond in such a manner and lost all of their plantings to late blight.


Of the late-blight strains that existed in 2009, Dr. Zitter says there was homogeneity that existed among the isolates since they represented the same clonal lineage. “You could almost put a bar code on the genotype because they were identical, they all behaved the same way, which is critical for identification.”


He adds that strains today have a much wider host range, with different genotypes, asexual reproduction and clonal lineages. These lineages may be more aggressive toward both tomato and potato. “With the new techniques that are available today, we can test a sample and within 24 to 48 hours we can tell what genotype it is,” he says.


In terms of the host range for late blight, it can infect plants such as petunia, hairy nightshade, tobacco and pepino (all members of the Solanaceae plant family) to name a few. This is a very wide host range and Dr. Zitter says that when he does greenhouse tours he always checks petunias in addition to tomatoes to be sure that late blight is not present.


“This is not the same disease that your father or even your grandfather knew because back then they were dealing with only US-1 (mating type A1) and it was only a concern for commercial potato growers,” he says.


During the early part of 2000, US-7 and US-8 were the main concern in potato and were of the A2 mating type. For tomato growers the lineages of concern were US-11 and -17 (both A1 mating type), with a limited preference for potato. All of these lineages showed resistance to the fungicide Ridomil, which had been the silver bullet available in the early 1990s when US-1 prevailed.


Fast forward to present day when growers need to be aware of the potential concerns for US-8 (A2, potato only), US-22 (A2, both crops), US-23 (A1, both crops) and more recently US-24 (A1, potato only). Fortunately US-22, -23, and -24 are all sensitive to Ridomil as determined by the Fry lab.


“Also, with many new chemistries, there are a plethora of new products available to help in emergency situations. Just make sure you rotate your chemicals,” he says.


Unfortunately, says Dr. Zitter, conditions on the battlefield have changed since the arrival of US-22, the strain that has infected both tomato and potato crops in the eastern United States and southern Canada from 2009 to 2011. “The isolate does have some staying power and can be expected this year as well,” he adds.


“When it was first identified, US-22 was found to be sensitive to Ridomil, and if we had known the genotype then, we could have advised growers to use one spray of Ridomil, which would likely have stopped it dead in its tracks. That’s why it’s so critical to know what genotype is at work in your field or in your greenhouse,” he says.


For potato growers, applying Ridomil alone in-furrow is not labelled for this use because it is difficult to get even coverage on the seed piece, but if mancozeb is applied to the seed tubers it will reduce the risk of the disease spreading from tuber to tuber prior to planting. “This is important not only for them but for tomato growers as well given the number of genotypes that move from one crop to the other,” he says.


Also new to the field since 2010 is US-23, which infects both potato and tomato rather aggressively, and is expected in 2012. It is sensitive to Ridomil. In 2011, it was first reported in Connecticut, then on Long Island, after a transplant grower was told he had late blight and reacted by destroying all of the plants that displayed the symptoms but keeping the ones he thought were clean. Shortly thereafter the inoculum on these plants reproduced and eventually spread to a number of New England states, and as far south as Pennsylvania.


“With US-22, US-23 and US-24, the big scary point we don’t know yet is about sexual reproduction because when you get the two mating types in the same field you certainly have the potential of their sexual mating and recombining into a different assortment. Subsequent oospore production means they have the potential to overwinter, which growers in Ontario might face on an annual basis. In New York, we used to see late blight about every five years, but that has changed in the last few years,” he says.


As to the future, Dr. Zitter says there are many unknowns. The organism is changing and the bottom line is that the plant breeders really need to focus on developing plants resistant to late blight.


For tomato growers and homeowners looking through seed catalogues, they want tomato cultivars that have both Ph2 and Ph3 genes for maximum late-blight resistance. “If it’s just Ph2 you can expect that late blight will develop,” he says. Some resistant varieties developed with both genes have performed well, including Mountain Merit and Defiant PhR for large reds, and Mountain Magic F1 for large cherry (a Saladette or Compari type).


Researchers at Cornell, other universities and some commercial breeders are working on new cultivars that are resistant or offer good tolerance to early blight, late blight as well as Septoria leaf spot. New crosses are being developed that confer high levels of genetic resistance for early blight and Septoria leaf spot that will allow for disease control with minimal or no fungicide applications, especially if a two-year rotation out of tomato is practised. He hopes new hybrids will be on the market in the next two years.


A national website, www.usablight.org/, is regularly updated by national contributors to pinpoint where late blight is currently reported, and growers are encouraged to log in. The site will even send messages to cellphones to tell growers when late blight is in their area. “It is timely information that you can use, and by the time it is posted, you will actually know what genotype it is so you can determine what kind of corrective action to take,” he says.


For updated information on the use of TOMcast ™ for determining the need for sprays to control early blight, Septoria leaf spot and anthracnose, visit the site at www.weatherinnovations.com/tomcast.cfm.

Published in Research

The sea-buckthorn berry is a little-known super fruit. The seed and pulp of the berry are loaded with vitamins, particularly C, A, and E. A single sea-buckthorn berry has more vitamin C than an entire orange and more vitamin E than a carrot. It also has high levels of beta carotene, omega-3 oils, and flavonoids.


Awareness of this nutritious fruit is on the rise. In June 2011, the fruit received positive reviews from Dr. Oz, the popular TV doctor who used to make frequent appearances on The Oprah Winfrey Show, and who now hosts his own program, The Dr. Oz Show. He discussed how the berry may help prevent wrinkles and constipation, and also aid in weight loss.


“As soon as the The Dr. Oz Show episode aired, we received phone calls from all around the world about what we’re doing with sea buckthorn,” said Bill Schroeder, a researcher with Agriculture and Agri-Food Canada’s (AAFC) Agroforestry Development Centre (ADC) in Indian Head, Saskatchewan. “We’ve been identified as one of the experts in that area.”


Sea buckthorn is a dense, deciduous shrub that can grow up to five metres tall. Its leaves are silvery green in colour, and its branches are typically thorny. The orange berries it produces are edible and have been referred to as the Siberian pineapple because of the berries’ taste and juiciness.


Originally, the shrub was imported to Canada from Russia in the 1930s as an ornamental plant. On the Canadian Prairies, sea buckthorn has been used primarily in wildlife habitats and shelterbelts to offer fields and farmyards protection from snow and wind.


In the not-too-distant future, it is possible that the fruit will be grown on the Prairies more often as a commercial crop, since its nutrient-dense fruit can be used in a wide range of products, such as jams, jellies, liquors, juices, and even skin ointments.


Other countries, mainly China and Russia, have been using sea-buckthorn berries in food products and skin creams for hundreds of years.


AAFC scientists are working to increase the commercial potential of sea buckthorn. AC-Autumn Gold, a new sea-buckthorn variety developed by researchers at the ADC, will be released in 2012. It has the potential to propel sea buckthorn into the commercial market because of its high yields and fruit that is easier to harvest than previous varieties. Not only does this variety produce fruit that is almost twice as large as previous sea-buckthorn varieties, but it is almost thornless, which makes it an easier plant for producers to work with. The berries on AC-Autumn Gold grow from five-millimetre–long stalks attached to the bush’s stem. This results in berries that are easier to hand-pick than previous varieties whose berries grew in tight clusters. Longer stalks, combined with large fruit size, also mean the berries can be harvested mechanically.


“I think there’s a real opportunity here,” said Schroeder. “If growers can efficiently and cost-effectively grow sea buckthorn, then a Canadian manufacturing industry around sea-buckthorn products could develop.”


AC-Autumn Gold is the result of more than 15 years of research performed by scientists at the ADC. It is the first sea-buckthorn variety to be unveiled by the centre since 2005, when Orange September and Harvest Moon were released through the Canadian Ornamental Plant Foundation and made available through commercial nurseries.

Similarly, farmers who wish to purchase AC-Autumn Gold must source it through Canadian commercial nurseries.
Perhaps one day, AC-Autumn Gold’s berries become a permanent ingredient in the jams and lotions found in Canadian homes.

Published in Food Safety

British Columbia blueberry growers have long relied on machines to pick their berries for the processing market. With labour becoming more scarce and more costly, many hope they can also use machines to pick for the fresh market.


The jury is still out on that.


B.C. Ministry of Agriculture berry specialist Mark Sweeney, Oregon State University professor Bernadine Strik and B.C. grower/packers Sukh Kahlon and Harvey Krause offered their insights into the topic at a panel discussion during the Pacific Agriculture Show in late January.


While she believes it is inevitable, Strik says “machines will have to change” before it becomes commonplace.


Sweeney agrees, noting current machines still cause a lot of bruising. Even non-obvious damage reduces shelf life so getting the berries to market quickly is “essential.”


That limits them to the local market, Krause says. “Over 80 per cent of fresh-market B.C. blueberries are shipped out and you can’t use machine-picked berries for that.”


Both he and Kahlon believe Duke is now the only variety suitable for machine harvesting for the fresh market. Duke blueberries “have a concentrated ripening window and their fruit tends to hold well,” Kahlon states.


They hold out some hope for the new Draper variety although it is so new to B.C. that “we won’t really know for another three to five years.”


Growers need to wait for more of the crop to ripen to make efficient use of machine picking. This simple fact works against use of machines for the fresh market.


“You can start to hand pick when only 30 per cent of the crop is ready but you need at least 70 per cent for machine picking,” Kahlon says. “Every day you wait exposes you to risk and may cause you to miss the higher-priced early season. If we had a variety which ripened in a two-week window, it would be better.”


That should reduce bruising because there would be less overripe fruit but could be self-defeating. The price premium growers count on early in the season could disappear if machines bring more volume onto the market than it can absorb.


All panelists stressed the need to prepare plants for machine harvest through severe, careful pruning. Machine picking requires straight rows, a narrow crown, trellised plants with no low branches and drip irrigation.


Even with better machines, “only the best growers with the best management will be able to do it,” Strik says.
Krause says growers need to be extra careful with a machine.


“The weather has to be just right, you need to be very gentle with the beaters and you must drive slow,” he cautions.
That’s a tough combination.

Published in Harvesting

British Columbia fruit growers weathered their second growing season with spotted wing drosophila (SWD) in 2011.

Cool, wet weather kept SWD levels low across most of the province and slowed infestations in some crops, but in the end SWD arrived in all of the fruit- and berry-growing areas of the province.


Researchers from across the Pacific Northwest region gathered at the Pacific Agriculture Show in January to share what they learned over the past season. Industry, academics and governments on both sides of the border have been working together to learn more about the pest to better inform control and management strategies.


Spotted wing drosophila, or Drosophila suzukii, is a small fruit fly that lays its eggs in ripe fruit on the vine. It is a threat to virtually all soft fruit and berries grown in British Columbia.


The alarm was raised when the pest was first discovered in a Fraser Valley berry field in the fall of 2009. It was initially believed that it would not survive the cold of winter. That was disproven when the pest emerged in the spring of 2010.


Researchers have found that the adult flies overwinter in the hedgerows and natural vegetation surrounding fields.

The flies have proven resilient to temperatures below -10 C, taking cover in the understory and ground debris to keep from freezing.


As temperatures warm, SWD populations start to build in the trees and wild hosts before they move into the borders of fields. The results of a study done by entomologist Tracy Hueppelsheuser from the B.C. Ministry of Agriculture and Lands showed a clear progression of SWD from the hedgerows into crop fields over the season.


“In blueberries, we caught flies in the hedgerows first, then about a week later in the field edge. That was in late May,” she says. “The field middle catches started in August, mostly during and after harvest.”


Results were similar in raspberries, where SWD was trapped in hedgerows and edges at the same time, but didn’t emerge in the middle of fields until two to three weeks later.


One of the most interesting findings for Hueppelsheuser was the delayed movement of SWD into berry crops. In a study looking at a comparison of trap catches of SWD to levels of fruit infestation, she found that early season fruit was free of SWD infestation. The results were consistent across all berry varieties in the trial, wild and cultivated.


“It was a surprise to me. I expected to see more flies as the season got later, but consistently with each variety, we did not see fruit infestation until mid-way through harvest,” she says.


“We had a pretty thorough monitoring system and collected a lot of fruit,” Hueppelsheuser explains. “I am confident in what we’re seeing, but I would like to see another year of this kind of data before I change the management recommendations.”


The late arrival of the flies could be a boon for growers looking to reduce pesticide applications. Currently, the recommendation to growers is to spray as soon as flies appear in traps, or the fruit starts to colour.  


A comparison of trap catches to fruit infestation emphasized the importance of using different tools to monitor SWD. Trap catch rates were shown to be highly variable within and between fields, including some sites where no flies were caught but larvae were still found in the fruit.  


“Don’t rely on the traps entirely to make your management decisions,” says Hueppelsheuser. “Traps are an important supplement, but making management decisions should be based on a variety of factors including crop development, time of year, monitoring methods and field history.”


The most accurate way to determine fruit infestation level is to put samples of ripe fruit in a sugar or salt solution.

After 10 to 15 minutes, larvae will leave the fruit and float to the surface, where they can be collected and counted.


Results gathered from the fruit infestation study supported the conclusions of the trapping work. They showed higher levels of SWD infestation in fruit collected from the edges of fields compared to the middle of the fields. The highest levels of infestation were found in fruit that remained in the field after harvest.


In addition to the variation within fields, there is significant variation in the level of infestation among different crops and varieties.


“The Elliott variety of blueberry appears to be much less susceptible to SWD – it had much lower rates of SWD than other late-season varieties,” says Hueppelsheuser. “Variety comparisons will be really important for growers to figure out how to risk-manage this thing. We will be doing more of that in 2012.”


Researchers also looked at strawberries for the first time in 2011, and the results are promising for growers. As with the other fruit, there was very little evidence of infestation until late in the season. On the whole, however, SWD was not a major concern.


“We found more Drosophila of other species than we did SWD in strawberries. Not every little white worm in a strawberry is an SWD larva,” Hueppelsheuser offers as a reminder to growers.


Growers looking for concrete results to base their management strategies on for the next season won’t find a silver bullet in the results of the past year. After a year of intensive fruit sampling and monitoring, the results showed that generally well-managed fields pay off with better fruit quality and less SWD.


Hueppelsheuser advises growers to consider weed management, mowing, drainage and access for harvesting, plant management and spraying, as part of their SWD management strategy.


“There are a lot of factors, but that’s what we saw,” she says. “When growers had bumpy fields, overgrown bushes or fruit on the ground, they tended to have more SWD.”


Once again, provincial extension specialists are encouraging an ongoing monitoring, holistic and region-based approach for effective SWD control. To keep up to date on monitoring and management information for growers for B.C., including pesticide registrations for 2012, visit http://www.al.gov.bc.ca/cropprot/swd.htm.

 

To build a better fly trap
The 2011 research season posed some challenges for SWD researchers, particularly when it came to catching the flies in traps.


In 2010, B.C. growers had two types of traps available to them, a commercially produced trap from Contech, and an improvised cup trap created by Agriculture and Agri-Food Canada researcher Sheila Fitzpatrick.


Since then, researchers have been trying different configurations and baits that will help trapping numbers more accurately reflect what’s going on in the field.


“Trapping worked well in the hot summer of 2010 when SWD were numerous in B.C. berry fields,” says Fitzpatrick. “However when SWD are less numerous, like in a cool rainy spring, we may need a different approach.”


U.S. Department of Agriculture (USDA) researcher Jana Lee from Corvallis, Ore., found that SWD prefer the colour red in the lab and field, and that traps with lots of entry surface caught the most flies. Others have developed traps with canopies, mesh tops, mesh side panels, and sticky bands. To date, no one has found the perfect design.


“Trap efficacy is climate-specific, and to some extent crop-specific,” says Fitzpatrick, who plans to continue work on trap design in 2012.


The number of traps, where they are placed and even the weather play a significant role in trapping success.


“In SWD, flies are seen resting in the canopy,” says Fitzpatrick. “Bushy crops provide humidity and shade so the insects don’t fly as much, but in open canopy crops they move more, and we find more in traps.”


Ultimately, the challenge is finding a bait that is as or more attractive to flies than the ripening fruit around them. Apple cider vinegar is the standard, and is particularly effective in the early season before fruit ripens. Adding a drop of dish soap to the bait lowers the surface tension of the liquid and catches more flies.


Another promising bait is a 40:60 combination of two per cent apple cider vinegar and 7.8 per cent red wine. Others have experimented with sugar and yeast combinations, as well as corn-based baits.

Published in Insects

Aphids, beetles and weeds are not new annoyances to sweet corn growers, but those who have successfully fought the battle with these trouble-makers may find it’s time to go to war again. Let the battle-leader in you take comfort that there are a few new weapons to launch into the field.


In a joint presentation at the Pacific Agriculture Show held in Abbotsford, B.C. in late January, Tracy Hueppelsheuser of the B.C. Ministry of Agriculture and Grant McMillan of ICMS, spoke about pest management and treatment tools for sweet corn. Because both experts are based in B.C., their observations took place in the region, but treatment options apply to crops across the nation.


Aphids are not a friend to sweet corn – they are the enemy. They are persistent, sap-sucking, destructive and prolific.

Because they ride wind currents easily, even a cornfield previously free of the pests may become a feeding ground with the aid of an ill wind.


The bird cherry oat aphid is a species that particularly enjoys B.C. corn. While it is incapable of over-wintering in Canada, every year it hitches a ride on the winds coming up from the warmer regions of the United States. Farmers obviously are challenged in their war with the aphid as prevention is difficult, if not impossible, for a pest that comes when it pleases.


The bird cherry oat aphid can be dark green or black in colour, winged or un-winged (youth are always un-winged) and range in size from 1/32 of an inch up to 1/8 of an inch. Not only can they impede pollination, fertilization and impact cob quality, but their presence and the black, sooty mold their honeydew leads to, is unattractive to retail buyers.


Although the aphids have natural predators – like lady bird beetles, green lacewings, syrphid fly larvae and parasitic wasps – these biocontrols are unlikely to be successful in adequate aphid control because their populations do not build up quickly enough to prevent crop damage. “Larger artillery” is generally required if aphids take hold during crop pollination and fertilization stages, which, if left unchecked will cause incomplete kernel development.


“They (the bird cherry oat aphid) are attracted to flowering corn, the tassels and silks, from June to September,” noted Hueppelsheuser. “They create tonnes of honeydew, which contaminates the tassles and husks.”


According to Hueppelsheuser, control of the pests at the tasselling stage will help prevent aphid damage based crop losses and will enable proper cob development. Two common, registered insecticides mentioned in her portion of the presentations are either ineffective or are no longer being manufactured. However, she noted the Group 4 insecticide, Assail (acetamiprid), delivers adequate control for one to two weeks.


“Assail is registered now that Pirimor is no longer available,” she stated. “It is best used early on (in the infestation).”


Assail is also registered on a variety of fruit and vegetable crops for other pests. It works through contact and ingestion. Thorough application of the product, ensuring good coverage of plant foliage, is the best way to ensure effectiveness.


One drawback of Assail is that it is toxic if sprayed directly onto bees, so growers must take care when applying it. It is also toxic to aquatic organisms. Hueppelsheuser recommends visiting the searchable pesticide label site of Health Canada at http://pr-rp.hc-sc.gc.ca/ls-re/index-eng.php to read the label and determine if the spray is right for your field. She encourages producers to keep watching the website for new products.


An occasionally returning soldier in the battle of the cornfield is the dusky sap beetle, which has a preference for cobs that may have been damaged by birds or other insects. About six millimetres in length, a “standard” cylindrical beetle body appearance and generally brown to black in colour, they are easy to spot on the surface of corn. The trouble is, because these pests are drawn to decaying plant material, like browning silks, the adults and larvae burrow their way into the cobs to dine on the kernels within where adults lay their eggs.


“The sap beetle shows up once in a while,” Hueppelsheuser said. “Keep and eye out for it.”


There are no registered pesticides for the dusky sap beetle, in Canada; however there are non-chemical practices to make use of to aid in beetle management. Unlike the aphid, the beetle does over winter in cornfields, so ploughing crop debris under to eliminate that home is effective. Choosing varieties of corn that have tightly packed kernels and long husks can also be effective in deterring the pests.


A new herbicide has been registered for use on sweet corn to assist with weeds. BASF agreed to apply the product Integrity to sweet corn, in addition to their testing of the product on field corn, McMillan noted as he took the stage.


As a result of the testing, this newly registered tool is labeled as a safe herbicide for sweet corn. Integrity is a mixture of Kixor and Frontier and was tested on six cultivars in fields in Abbotsford and Yarrow, B.C., resulting in 80 per cent or greater control of weeds.


In his presentation, McMillan detailed that 1/4 to 1/2 inches of moisture is required within seven to 10 days of product application to ensure efficacy in control of grasses and broad leaf weeds. Even though it is a broad spectrum weed control product, Integrity was tested at a double spray rate and was found safe.


This is good news for producers as it ensures no crop injury will occur in the case of overspray or an accidental second pass of the product on corn.


As is the case with any good weed management practice, McMillan concluded his presentation with the note, “You must rotate products through the (herbicide) groups to prevent weed resistance and mutation.”


Certainly going to the battlefield can be daunting, but with the right weapons in hand, you may just win the war for your sweet corn.

Published in Research

University of Manitoba and University of North Dakota trials suggest that fumigation may be an effective method of killing or controlling verticillium.


Researchers Mario Tenuta from the University of Manitoba and Neil Gudmestad from the University of North Dakota recently made presentations at Manitoba Potato Production Days in Brandon, Man., outlining the results of that research thus far.  


Verticillium dahliae is the major culprit in the early dying of potatoes, explained Tenuta, adding that verticillium wilt is characterized by wilting leaves and browning in the stems. Tenuta noted the survival structures of verticillium, called microsclerotia, can survive in the soil for years.  They are resistant to light, heat and freezing temperatures.


Verticillium dahliae, he said, hurts the development of larger tubers in particular. The disease stunts their growth and cuts their weight.


The fight against Verticillium dahliae begins with soil testing in the spring before planting.


“You need to look at the number of propagules in the soil,” Tenuta said.  “You are usually talking about 10 to 15 verticillium propagules in the soil per gram before you have an issue.”


Tenuta and his team of researchers have been studying the use of fumigation – toxic gases – in killing verticillium propagules in the soil. Metam sodium – better known under the trade name Vapam – is the chemical most commonly used in the Pacific Northwest and California.


According to the label, for Vapam to be effective, growers need a decent soil temperature – producers can’t wait too late into the fall in most of Canada – with spacings of about six inches between entry points, explained Tenuta. He suggested that Vapam should be injected at least six inches into the soil although Neil Gudmestad’s research indicates the most effective treatment involves injecting Vapam 10 inches into the ground.


“We tried injecting Vapam at six inches and at 10 inches,” Gudmestad said. “The deeper application seems to be more effective at controlling verticillium wilt. We believe this is because the potatoes’ true roots lay below the seed piece.”


Gudmestad’s studies also demonstrated that, contrary to current belief, fumigation targeting Verticillium dahliae propagules can be carried out in temperatures as low as 39 F.


Tenuta said fumigation should be completed in the fall to give the toxic gas time to dissipate well before spring planting. The gas kills other organisms in the soil as well as the verticillium propagules.


The University of Manitoba soil ecologist described trials that his department has been conducting with Vapam in the Shilo area in western Manitoba beginning in 2007.


“We alternated Vapam and non-Vapam treatments on strips of land,” said Tenuta. “[In some strips] we had added verticillium to the soil. The other [strips] contained naturally present verticillium.”


While Vapam was quite successful in killing verticillium propagules in the soil, ultimately reducing verticillium present in the soil by 50 per cent, the chemical treatment had no effect on reducing the incidence of verticillium wilt in the plant.


“The application was done in spring, so it wasn’t a completely fair test,” he said. “It should be done in fall before potatoes.”


Another series of trials that Tenuta and his team have been carrying out in the Carberry, Man., area point to compost from animal manure and yellow mustard meal as equally effective in protecting potato plants from verticillium infection.


The team’s most recent trials, carried out over the past season in six different locations in Manitoba, have confirmed the earlier findings that verticillium is killed by the product.   


“Some soils are high in verticillium propagules but the potatoes aren’t showing much disease,” he observed. “We think maybe the amount of organic matter in those soils is controlling the verticillium naturally. We need to ask if there is need for application on such soils.”


Gudmestad noted that crop rotation has also been shown to control verticillium propagules but added that a two-year rotation isn’t enough. Crop rotation needs to be carried through for three or four years to be most effective, he said.


Gudmestad noted that metam sodium seems to be most efficacious in sandy loam soils.


Tenuta also spoke about promising research involving the use of DNA to rapidly and more precisely provide soil testing to determine verticillium levels in soils.

Published in Research
Page 54 of 55

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