Pest Control

“Although potato psyllids have been known in the past to cause some damage themselves, the real concern is mainly from the bacterium, and we don’t have it in Canada yet. But if our potato psyllid population continues to increase – as it has done during 2013 to 2016 – and if it becomes more continuous with U.S. populations, and if tomato and potato plants (and tubers) are shipped more frequently, then it could arrive,” says Dan Johnson, an entomologist at the University of Lethbridge. | READ MORE

The Prairie Pest Monitoring Network (PPMN), now in its 20th year, continues to provide timely crop insect pest risk and forecasting tools for growers and the industry across Western Canada. As technology and forecasting tools advance, so does the ability of the network to provide relevant insect pest information related to scouting, identification and monitoring tools and information, plus links to provincial monitoring and support relevant to the Canadian Prairies. | READ MORE

 

An Islander has heeded the call to mass manufacture a trap to fight P.E.I.'s wireworm pest.

Nov. 28, 2016, Prince Edward Island – Health Canada's proposal to phase out a pesticide over three years will have a significant impact on Island farmers looking to control the Colorado potato beetle, says the P.E.I. Potato Board. | READ MORE

As part of the regular review process, Health Canada has completed its re-evaluation of imidacloprid, and has published its draft risk assessment for public comment. The assessment proposes current use of imidacloprid is not sustainable, and the levels of this pesticide that are being found in waterways and aquatic environments are harmful to aquatic insects, such as mayflies and midges, which are important food sources for fish, birds and other animals.



Concentrations of imidacloprid in surface water can range from non-detectable to, in some rare cases, levels as high as 11.9 parts per billion, according to Health Canada. Scientific evidence indicates levels above 0.041 parts per billion are a concern.

To address the risks identified, Health Canada has published a proposed risk management plan for public comment, which includes a proposed three-year phase-out of agricultural uses of imidacloprid in order to address risks to aquatic insects. In some cases, where there are no alternative pest control products available, a longer phase-out transition period of five years is being proposed.

In a press release, Health Canada said it is consulting on these proposed mitigation measures, and the final re-evaluation decision and risk management plan will take into consideration any comments received during the consultations. 

The consultation phase includes a 90-day commentary period in addition to a multi-stakeholder forum that will discuss any proposals for potential alternative mitigation strategies that would achieve the same outcomes in a similar timeframe. 

Any proposals for continued registration will need to clearly demonstrate concrete actions to ensure levels of imidacloprid in water will be reduced below the level of concern.

Based on the findings of the re-evaluation assessment on imidacloprid, Health Canada is also launching special reviews for two other widely used neonicotinoids: clothianidin and thiamethoxam. These special reviews will examine any potential risks these pesticides may pose to aquatic invertebrates, including insects, as they are also being detected frequently in aquatic environments.

In the press release, Health Canada said it will provide updates as new information becomes available.

Bayer has launched Velum Prime nematicide, the first non-fumigant nematicide registered for potatoes in Canada.

Velum Prime is a new mode of action and chemical class (pyridinyl ethyl benzamide) for nematode protection. It offers growers effective nematode protection that helps sustain plant vigor and maximize crop yield potential, according to a press release.

Recent trials of Velum Prime demonstrated consistent yield and quality increases and reduction in plant parasitic nematodes, including root lesion, root knot and potato cyst nematode.

Velum Prime is applied in-furrow at planting. It comes in a liquid formulation that offers reliable efficacy at low application rates making it ideal for use with existing in-furrow application equipment. Applied in-furrow, Velum Prime offers the added benefit of early blight protection.

Maximum residue limits for Velum Prime applied in-furrow are in place supporting trade in North America and Europe. Additional MRLs supporting trade in other key export countries, including Japan, are expected early in 2017.

For more information regarding Velum Prime, growers are encouraged to talk to their local retailer or visit cropscience.bayer.ca/VelumPrime.

 

New hope is on the horizon for potato growers engaged in the ongoing battle against Colorado potato beetle (CPB). Researchers are currently field-testing one of the most effective controls ever developed for the potato’s chief insect villain, and it is entirely chemical-free.

RNA interference (RNAi) is a biological process whereby RNA (ribonucleic acid) molecules activate a protective response against parasite nucleotide sequences by inhibiting their gene expression. In other words, it is the method by which organisms – including pests such as CPB – defend themselves against threats and regulate their own genes. But the same process that is used by a beetle to protect itself can be used to destroy it when it consumes the long double-stranded RNA (dsRNA) in genetically modified plants.

Since 2009, researchers at the Max Planck Institute in Potsdam and Jena, Germany, have been developing genetically modified potato plants to enable their chloroplasts to accumulate dsRNA targeted against essential CPB genes. After feeding on a potato’s leaves – and ingesting the dsRNA – the beetles in the study showed 100 per cent mortality within five days.

Why chloroplasts, rather than plant cell nuclei? In past breeding projects, expression of dsRNA in potato plants’ nuclei has proven inefficient because natural RNAi pathways in nuclei prevented the plant from producing enough long dsRNA. But long dsRNA are free to accumulate in chloroplasts – which have no RNAi mechanism – and the plants are fully protected against CPB.

According to Jiang Zhang, a professor with the College of Life Science at Hubei University in China, and the lead on the project, the technology shows great promise for the future of pest management, but there are no immediate plans for commercialization until all regulatory hurdles have been overcome.

“We encourage more scientists and industry involvement in this field for a better future,” Zhang says. “There is still a long way to go to make it really useful in daily life and be accepted by customers.”

RNAi-based biocontrol
RNAi for control of CPB has also gained significant momentum in private research and development. Monsanto and Syngenta have both devoted major investments toward the technology.

In early 2015, Monsanto’s BioDirect technology platform targeted at CPB advanced to Phase 2 – early product development – of the company’s research and development pipeline. The product will have to complete advanced product development and pre-launch before broad commercialization early in the next decade.

While the principle is the same, Monsanto’s product works differently than Max Planck’s modified potato plant: it is sprayed onto the plant’s foliage. Rather than expressing dsRNA in its leaves, dsRNA is applied exogenously to the plant.

“The Colorado potato beetle consumes the leaves of the potato plant where we can focus the BioDirect application, versus needing a plant to produce the dsRNA targeting the pest below-ground where sprays cannot reach,” explains Greg Heck, weed control team lead for Monsanto’s chemistry technology area.

Heck says there are thousands of dsRNA naturally present in host plants that serve a variety of functions, and beetles consume and incorporate dsRNA all the time. “When targeting them for pest control, we seek to supply one additional dsRNA that will turn down a specific gene critical to their ability to feed and grow on the plant.

“Field research conducted on our BioDirect treatment for Colorado potato beetles has already demonstrated some early positive results. This includes reduced Colorado potato beetle larva infestation and plant defoliation in multiple geographies.”

Syngenta’s most advanced RNA-based biocontrol targets CPB in potato – and is also applied via a spray. The company has tested the product in multiple geographies over several years with positive results, says Luc Maertens, Syngenta’s RNAi platform lead based in Belgium. The company hopes to commercialize the product early in the next decade pending continued development and regulatory reviews.

Maertens says the company’s biocontrol is highly selective and starts to work before CPB can cause too much damage.

“The biocontrol is not systemic [in the plant], nor does it work through contact,” he says. “It does not change or have any effect on the DNA of the pest, nor does it involve genetic modification of the plant.”

No technology can work forever, however. Insect resistance to RNAi is a potential risk – one companies and researchers alike are keen to avoid so the technology has maximum benefit and longevity.

Maertens says that as resistance emerges to existing technologies, and the pest spectrum shifts along with climate change and other factors, growers’ needs will change. “Those challenges cannot be answered by only one technology,” he says. “It is imperative to gain insights into probable resistance mechanisms to RNAi triggers in insects, to monitor possible resistance in the field, and to support the use of the technology with appropriate stewardship requirements.”

Of the two methods of RNAi application (genetic modification and spray-on), Zhang believes the former might be better for growers. “Applying dsRNA exogenously is much less cost-effective than expressing dsRNA in the plant itself,” he says. “Spraying may also cause other potential problems in the environment.”

RNAi is not meant to be a silver bullet and should be used as part of a multifaceted pest control strategy. Regardless of the method of application, RNAi may soon be working in a field near you.

 

 

 

Nov. 10, 2015 – It is never too early to find out about the new crop-protection products, reminds Eugenia Banks, potato specialist at OMAFRA, in her latest potato update.

These new products were recently registered and should be available for the 2016 season. Here is a list of pesticides, some with new active ingredients:

Trade name Application method Disease or insect
Aprovia
(Syngenta) Group 7
In-furrow *Suppression of Rhizoctonia stem canker, stolon canker and black scurf
Sercadis 
(BASF) Group 7
Foliar and aerial Control of early blight and white mould.
Use of a non-ionic surfactant is recommended
Sercadis 
(BASF) Group 7
In-furrow

Control of Rhizoctonia canker

Voliam Express
(Syngenta)
Group 3A and 28
Foliar

Control of black curworm, variegated cutworm, armyworm, potato psyllid
Active ingredients: pyrethroid + diamide

Agri-mek SC
(Syngenta) Group 6
Foliar

Control of potato psyllid and spider mites (not a pest in Ontario)

Control is at least 85 per cent control
*Suppression is 65 to 85 per cent control
"May provide some control" is less than 65 per cent control.

There are also label changes to some registered products. For instance, the label of Rampart (phosphite) has been expanded to a foliar application for suppression of late blight and pink rot. In general, any product that suppresses late blight should be tank mixed with a compatible control product. A better approach would be to tank mix two compatible control products. If the weather is favorable for late blight, this disease can explode and devastate potato fields very quickly.

There are new registrations for potato psyllids. This tiny insect is the vector of the bacterium that causes zebra chip. This past season, I placed several yellow sticky cards in three Alliston fields to monitor for potato psyllids, but no potato psyllids were caught on the cards. In the past, this insect has been reported in British Columbia, Alberta, Saskatchewan and Quebec. Psyllids were found in Ontario a few years ago, but only in a greenhouse, not in the field. It is always good to have registered products available for the control of potential pests. There will be more updates to come as new products are registered. 

Severe Colorado potato beetle larval damage to potatoes. Photo by Vikram Bisht, MAFRD.

Colorado potato beetle (CPB) has been a challenging pest for potato growers for more than a century, and today it continues to be the most damaging insect defoliator of potatoes across Canada and the U.S. If uncontrolled, growers suffer yield losses and potential crop failure in potato crops and other field vegetable crops such as tomatoes and eggplant. Growers continue to rely on insecticides for control, however CPB is very adept and successful at developing resistance, creating additional challenges for researchers, industry and growers.

 With increasing potato farm size and repeated use of effective insecticides, there has been high selection pressure on CPB to survive. Insecticide resistance develops largely from the overuse and repeated application of chemicals with similar modes of action that increase the selection of the resistant individuals in the population. “Colorado potato beetles resistant to DDT were first reported in 1955, and have since developed resistance to over 51 different insecticides, including imidacloprid and eight other neonicotinoids in the U.S.,” Ian Scott, research scientist with Agriculture and Agri-Food Canada (AAFC) in London, Ont., says. “Colorado potato beetle resistance in Canada has developed more slowly, with the first findings of resistance in 2003, to imidacloprid (Admire), the first neonicotinoid registered in Canada, and increasing reports of problems and crop failures in Ontario and Quebec by 2007.”

 In 2008, Scott and colleagues initiated a four-year project to survey CPB neonicotinoid resistance in Canadian potato fields. Growers and agronomists from across Canada sent live samples to AAFC every summer. “We partnered with different chemical companies on the project and, depending on which products were surveyed in a particular year, we conducted bioassays in the lab,” Scott says. “We were able to screen quite a few populations of Colorado potato beetle through the bioassays. We were trying to confirm what growers and extension people were seeing related to resistance concerns with registered neonicotinoid uses. Also, some companies were planning to introduce new products of the same class or different groups and wanted to see if there was any potential cross-resistance with the older products.”

 The results of the four-year survey confirmed previous studies showing that many CPB populations have become less sensitive to imidacloprid and that cross-resistance with the second-generation neonicotinoids thiamethoxam and clothianidin is a growing concern. Scott adds the survey also demonstrated cross-resistance is on the rise.

“Using comparisons of Colorado potato beetle mortality generated from lab bioassays with Admire, Actara and Titan, a strong positive correlation indicated there is potential for cross-resistance between these three neonics,” Scott notes. “However, cross-reaction correlation was weaker between neonic Admire (Group 4A) and diamide insecticide Coragen (chlorantraniliprole, Group 28), indicating the cross-resistance between these classes is less likely to develop.”

 According to Vikram Bisht, plant pathologist with Manitoba Agriculture, Food and Rural Development, the Atlantic provinces, and Quebec and Ontario have had a greater problem with CPB resistance to Group 4 insecticides. “However, Manitoba has seen some population shifts to resistance,” he notes. “Alberta currently does not have serious issues and so far even older chemistries appear to still be effective there. Resistance to the newer insecticides is highly likely if the products are continuously used without proper insecticide resistance management practices being applied. It is important to rotate chemistries to prevent multiplication of insecticide resistant populations.”

 Vikram adds CPB populations collected from treated fields in Manitoba in 2012 and 2013 and tested by Scott were also found to be imidacloprid resistant (with less than 30 per cent mortality) or showed reduced sensitivity to clothianidin or thiamethoxam (with 30 to 70 per cent mortality). Repeated use of similar mode-of-action insecticides may often lead to development of cross-resistance against newer insecticides, even though they had not been previously applied. Therefore, resistance against clothianidin and thiamethoxam has a greater chance of appearing in imidacloprid-resistant CPB populations.

“Generally, every commercial grower treats seed potato for Colorado potato beetle and in most cases control is quite effective,” Bisht says. “In areas where resistance is developing and in situations where growers also need to use a foliar application for in-crop control, they must make sure to use a different chemistry in-crop than was used for seed treatment. There are at least five different seed treatment or in-furrow chemistries and a few other chemistries for in-crop, so growers do have options available. Growers should make rotating insecticide chemistries a priority whether or not they have resistance concerns, as it is good practice to ensure long-term use of the good tools available.”

 Bisht adds crop rotations of two years or longer are needed to be effective. However, fields must not be adjacent to last year’s crop. “Short distances from previous potato crops reduces the advantage of crop rotation, since the overwintering Colorado potato beetle adults from last year’s field can easily crawl to adjacent fields. Also, Colorado potato beetles can fly short distances during warm days and can easily move 100 to 200 metres.”

New research and management options
“We are working on other projects focused on understanding the mechanisms responsible for resistance of Colorado potato beetle through molecular and biochemical analyses,” Scott says. “We have maintained a number of Colorado potato beetle colonies in the lab for use in various projects; for example, screening alternative biopesticide products and the use of natural plant compounds as insecticide synergists.”

 One recent project studied the potential use of dillapiol, the main constituent in Indian dill (Anethum sowa), as a synergist to help improve insecticide activity and longevity, and control of resistant pest populations. Synergists have a long history of use, one of the most frequently used ones being piperonyl butoxide (PBO) in combination with the natural insecticide pyrethrum. PBO is a very effective synergist but has related toxicological concerns.

“Our laboratory trials testing of pyrethrum alone versus pyrethrum combined with dillapiol indicated that the synergist increased the activity of pyrethrum against insecticide-susceptible and -resistant Colorado potato beetle,” Scott explains. “In field trials, both the PBO and dillapiol synergized pyrethrum had 10 times the efficacy of pyrethrum alone. We continue to work on dillapiol and other natural plant-derived synergists that may offer compounds with improved health and environmental safety and potential for organic certification.”

 Research continues on other strategies to help growers manage the challenges of CPB. “There continues to be a focus on the development of new varieties with Colorado potato beetle resistance, however transgenic varieties have not yet been accepted by the market,” Bisht says. “Plant breeders are also using conventional breeding to introduce natural resistance genes from wild species, and hopefully in the future varieties will become available.

“There are other cultural practices that can be options for organic or smaller growers, but so far most are not practical for larger commercial growers. There is a new biological insecticide available – Novodor (Bacillus thuringiensis subsp. tenebrionis, strain NB-176) – but it is not currently used by commercial potato growers. Plastic-lined trenches on field edges could be effective for small farms, which trap Colorado potato beetle and prevent movement into the field.”

 Considerable efforts continue to be focused on addressing resistance. Scott and Bisht remind growers everyone must do their part to be vigilant in monitoring and scouting for CPB resistance, follow proper insecticide resistant management practices and alternate classes of insecticides available.

“The survival of beetles after an insecticide application could be due to a variety of factors, including improper coverage, failure to apply the full rate of insecticide, or precipitation soon after application and existence of actual insensitivity (tolerance/resistance) to the insecticide,” Scott says. “It is very important for growers and industry to practice good stewardship and maintain the use of these products as long as possible. It takes a considerable [amount of] resources, time and funds to develop new chemistries, so protecting the tools we have as long as possible is a best practice.”

 

Burn, beetle, burn
In February 1994, Potatoes in Canada magazine, a sister publication to Top Crop Manager magazine, published a story with an eye-catching headline: “Burn, beetle, burn.”

The story explains that in the summer of 1992, field trials began on an eight-row flamer designed to control Colorado potato beetles (CPB) that had recently demonstrated resistance to traditional chemical treatments. The flamer tests were initiated by ICG Propane, in co-operation with the Ontario Ministry of Agriculture, the University of Guelph, and growers in Alliston and Leamington, Ont.

The trials showed that flaming had several mechanisms for limiting beetle damage. The most obvious was that it could kill the beetle adults outright. But the trials also shows there were three secondary controls: First, flaming caused sufficient damage to the CPB so that it died in the near term; second, if eggs and antennae were damaged, the beetles became disoriented and, thus, unable to feed or mate; and third, the heat from the flaming resulted in a high mortality for the eggs already laid.

The trials showed that using the propane flamer in the spring for overwintering adults gave control of 70 to 80 per cent of the adult beetles and also killed nearly 50 per cent of the eggs. Late season control, the time of top killing, gave 95 to 100 per cent control of adult CPB. In addition, the 1994 story stated growers were “astonished at the level of weed control that came as a result of the flaming activity.”

Even more interesting was the low level of plant damage from the flaming. The story states that in almost all locations of the study, slight plant injury similar to that observed when plants are hit by a late frost did occur. However, the growing tip of the plant was not affected, and most injury was unnoticeable after about a week. “Potato yields taken at four of the test sites showed no difference in yield between flamed and unflamed areas.”

At the end of the day, physical methods to control Colorado potato beetle and other pests are seeing resurgence, as the very real threat of insecticide resistance increases.

 

A new study at the Harrington Research Farm in P.E.I. is examining how to make buckwheat crops an even more effective and practical option for potato growers looking to control wireworm. Photo by AAFC.

Growing two years of buckwheat in a potato rotation is effective at managing wireworms, one of the toughest pest problems for potato growers. But how does buckwheat actually affect wireworms, and can we make buckwheat rotation even more effective and practical for growers? A rotational study is underway on Prince Edward Island to answer these questions.

The P.E.I. study is part of a major project to investigate different strategies for dealing with wireworms, led by Christine Noronha, a research scientist with Agriculture and Agri-Food Canada (AAFC). The project, funded by AAFC, involves AAFC scientists across the country because wireworms cause serious problems in many regions and many crops.

Wireworms are the soil-dwelling larvae of click beetles. Canada has about 30 wireworm species of economic importance. In most species, the beetles lay eggs in the soil in the spring. A few weeks later, the larvae hatch. The larval stage lasts about four or five years, depending on the species. Then the larvae pupate and the adults emerge from the soil in spring.

In potatoes, wireworms tunnel into the tubers, reducing marketable yield. The tunnels can also be entry points for potato pathogens.

Noronha has been conducting wireworm research in P.E.I. for over a decade. Her rotational studies show growing either brown mustard or buckwheat as a cover crop for two years before growing potatoes can reduce tuber damage by about 80 per cent or more. Brown mustard is known to release chemicals into the soil that control wireworms, but the reasons for buckwheat’s effect on wireworms are not yet known.

AAFC research scientist Aaron Mills is leading the new P.E.I. buckwheat agronomy study. It is taking place at the Harrington Research Farm and runs from 2014 to 2016.

“Christine Noronha has done an excellent job at figuring out how to control wireworm with buckwheat; it’s now another tool in the toolbox for controlling wireworm. A big part of this new buckwheat study is to find out how and why buckwheat affects wireworms,” Mills explains.

“We also want to establish local protocols for how to deal with buckwheat in the rotation, so growers wouldn’t be as intimidated by the potential for buckwheat to become a weed problem, and to establish some protocols for managing buckwheat as a grain as well.”

Better understanding of how buckwheat impacts wireworms could potentially lead to advances that enhance wireworm control. For instance, one possibility is that buckwheat is releasing compounds into the soil that kill or suppress wireworms directly or perhaps affect other components of the soil ecosystem in ways that make conditions less favourable for wireworms. If such compounds are released when buckwheat foliage decomposes in the soil, then the most effective wireworm control strategy might be to disk the plant into the soil as a green manure. Or it may be best managed as a mulch, in which case flail mowing as a green manure may be best. If the compounds are released by the roots, then perhaps it might be better to let the buckwheat crop grow for a longer period before terminating it. If buckwheat produces compounds that deter other insect pests or pathogens, in addition to wireworms, then it could provide even greater benefits in the crop rotation. In the longer term, perhaps buckwheat lines could be selected that have higher levels of those compounds, or perhaps a bio-insecticide could be developed using the compounds.

A key aspect of successfully including buckwheat in a crop rotation is to ensure volunteer buckwheat doesn’t become a weed issue. “Traditionally buckwheat has been grown as a weed control measure, and some growers are concerned about growing it because it can become a weed itself if you let it grow too long and go to seed,” Mills says. He explains buckwheat grows very well in P.E.I.; the seedlings emerge and grow quickly, enabling the crop to outcompete weeds. As well, some research indicates buckwheat releases chemicals into the soil that inhibit the growth of certain plant species. Those characteristics make buckwheat great at fighting weeds, but can also make volunteer buckwheat a problem for the next crop.

Although letting buckwheat go to seed is a weed risk, growing buckwheat for grain would be an important opportunity for growers to obtain some income from growing two years of buckwheat for wireworm control.

“Right now I would say the majority of growers on the Island are growing buckwheat for wireworm control, but I think people are interested in growing it as a crop for grain as well,” Mills notes. “I think the main export market for buckwheat is for use in noodles in the Asian market, although it has been grown in places like New Brunswick to make flour for buckwheat pancakes. And there may be opportunities in the health food industry; for example, buckwheat oil is reported to have some bioactive benefits.” Buckwheat also attracts pollinators and is used for honey production.

Wireworms, organic matter, microbes and more
Mills’ study is comparing five different three-year potato rotations. Three of the rotations involve two years of buckwheat and are comparing three strategies for terminating buckwheat: disking, flailing, and desiccating and then harvesting it for grain.

“For termination through disking, we wait until the lower seeds start to drop off and then we use a set of disks to incorporate the aboveground crop material into the soil. For termination through flailing, we wait for the lower seeds to start to drop, and then go in with a flail mower and completely flail off the top of the aboveground biomass, leaving the residue on the top of the soil surface, almost as a smothering effect. And to manage buckwheat for grain, we desiccate the crop and then take it off with a combine,” Mills says.

He adds, “We wait for the lower seeds to start to drop off when flailing or disking because we’ve found that buckwheat turns to jelly when you flail or disk it – the remaining residue breaks down fairly quickly. So rather than ending up with bare soil going into the winter, we wait for the lower seeds to start to drop off to make sure there will be a little bit of cover going into the winter.”

For the three buckwheat treatments, Mills’ research team is measuring factors like buckwheat biomass and seed yield, as appropriate.

The other two rotations in the study are traditional three-year potato rotations used in P.E.I.: barley underseeded with clover and then potatoes; and barley underseeded with a grass and then potatoes. These traditional rotations have benefits for soil conservation, but they favour the spread of wireworms because the beetles prefer to lay their eggs in grassy areas.

The researchers will be gathering data on such factors as potato yields and the levels of wireworm damage in the tubers for the five rotations.

As well, they will examine effects of the different rotations on water quality, soil organic matter content and soil nutrient levels, so nutrient management specialist Judith Nyiraneza and water quality specialist Yefang Jiang are involved in the study.

“Although any green cover on the soil helps to reduce erosion, the study will be examining whether or not buckwheat is particularly good at preventing erosion or building up soil organic matter,” Mills says. “I think the jury is still out on whether buckwheat is a soil builder or not.”

Buckwheat’s effect on soil nutrients also needs to be clarified. Some previous research has suggested buckwheat may make nutrients like phosphorus more available to the next crop, while other sources suggest buckwheat may reduce levels of certain nutrients.

To better understand how buckwheat controls wireworms, Christian Gallant, a graduate student from Dalhousie University, is looking at the soil organism communities in the plots, especially the nematode communities, and also the fungal and bacterial communities. He will be examining how species diversity and populations change through the course of the growing season and with the different crops.

Mills explains the value of examining nematode communities: “Most people focus on the plant parasitic nematodes. Those nematodes feed on plant roots, and the damage from their feeding also opens up spots for pathogens like Verticillium to enter the plant’s root system. But there is a whole other side of the nematode community. They all have specific jobs to do; there are bacterial feeders, fungal feeders and predators that feed on other nematodes and even mites. By studying the overall nematode community, we can get a snapshot of how things are happening biologically in the soil.”

In addition, researchers will be testing the soil for buckwheat compounds that could be affecting soil organisms. “We’re trying to figure out if buckwheat is actually releasing chemicals into the soil that are affecting the soil pest populations, or if buckwheat is just a non-host for some of these pests,” Mills says.

With one field season completed so far, Mills is looking ahead to the results from 2015 and 2016. “By the end of 2015, we’ll have a really good idea of how the different buckwheat treatments affect soil organisms, nutrients and organic matter, [and water quality]. And by the end of the study’s third year, we’ll have an excellent idea of how everything affects potato production.”

In the meantime, growers are welcome to visit the Harrington Research Farm to see the plots and learn more about the study.

 

 

 

By Dow AgroSciences Canada

 

Oct. 16, 2014, Calgary – Canadian potato producers can now apply Delegate Insecticide to control Colorado potato beetle and European corn borer on product that could be destined for Japan.

May 27, 2014, Regina – FMC has received registration for bifenthrin, the active ingredient in Capture insecticide, for potato growers.

Wireworms have become one of the major pests in potatoes for numerous growing regions of Canada (see the Potatoes in Canada Summer edition cover story). 

“In potatoes, Capture insecticide is to be used as an in-furrow spray application at-planting," according to Mark McMillan, FMC's business manager for Eastern Canada, in a press release. This spray application is meant to create a zone of protection around the mother tuber and developing daughter tubers later in the season. 

Capture will be distributed by UAP.

July 19, 2013, Alberta – An Alberta Agriculture specialist says that conditions are excellent in most areas of Alberta for the development and spread of late blight.

“In recent years, late blight of potato and tomato has been found in varying degrees in various parts of the province,” says Robert Spencer, commercial horticulture specialist, Alberta Ag-Info Centre, Stettler. “So far this growing season, late blight has not been found in Alberta, but conditions are excellent for its development and spread.

“A great deal of effort has been expended to minimize the seasonal impact and limit the ongoing spread of this disease. As a result, the number of detections has been significantly reduced, but we need to stay vigilant.”

Spencer says the following conditions, all of which have been seen this growing season, favour the development of late blight:

  • significant amounts of moisture, falling in regular intervals (days without any precipitation have been rare)
  • high humidity (sometimes approaching 95 per cent)
  • heavy dews and long leaf wetness periods
  • moderate temperatures
  • warmer nights (night time temperatures are not falling below 9°C)
“It is recommended that all growers of potatoes and tomatoes be extra vigilant to try and catch any diseased material early on before a significant outbreak occurs,” says Spencer. “Producers should monitor fields for potentially infected plants. Protective fungicide applications can be made in commercial operations.”
Colorado potato beetle pressure was relatively low in Canada in 2009 compared with some years, but growers must stay aware to both control populations in their fields and effectively manage developing resistance to Group 4 insecticides.
Although European corn borer pressure during the early part of the 2009 growing season was less than in 2008, by the middle of last September, tell-tale broken stalks and entry holes were surprisingly commonplace in the potato fields of Prince Edward Island. “The European corn borer (ECB) has become an annual pest here over the last few years,” says Brian Beaton, potato co-ordinator with the PEI Department of Agriculture. “The pressure varies from season to season depending on the weather conditions, but most years we see some damage.”
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