Squashing SWD fruit fly
From Europe to North America, researchers test new opportunities for control. | 8
What difference a drone makes Trials show potential for pest control. | 14
How to find good help
Try and see how candidates perform on the farm before hiring them. | 16
April 2020
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What a difference a drone makes
Preliminary results of field trials show potential for
The brown marmorated stink bug is shaping up to be a problem for late-season tree crops like pears and hazelnuts in B.C.
Squashing
Researchers
Tree
BY RONDA PAYNE
BY PETER MITHAM
How to find good help
Try to see how candidates perform on the farm before hiring them.
BY SEBASTIAN LECK
The theme of April’s issue is pests and diseases and our cover story is all about stink bugs. For some, stink bugs are a pest, for others, they’re just boring bugs. But the brown marmorated stink bug (BMSB) is anything but boring.
BMSB is an invasive pest from Asia that is prominent in the U.S. with no major enemies to keep its population in check – until recently. A 2018 Science Magazine feature story revealed: “Scientists spent years on a plan to import this wasp to kill stink bugs. Then it showed up on its own.”
The article sets the stakes: In 2010 stink bug damage cost midAtlantic apple growers $37 million. It describes the obstacle: without any natural enemies, the brown marmorated stink bug has been free to roam across 43 states and Washington, D.C. Then, the article offers a glimmer of hope: USDAARS scientists traveled to Asia to find natural enemies of the stink bug to bring back home.
The samurai wasp, a small
had immigrated on their own.
Since then, according to the 2018 article, the wasp turned up in 10 states and Washington, D.C., and so far, research studies are seeing the samurai wasp emerge as a promising biocontrol without harmful side effects.
Why is this important? News like the samurai wasp immigrating on its own gives hope. Invasive predators can help us deal with invasive pests – assuming they don’t upset the ecosystem balance too much. It reaffirms that our environments are always in a state of flux and our ecosystems are delicate, dependent, and unpredictable.
So what threat does BMSB pose to Canadian growers today, and what’s the status of samurai wasps north of the border? Read the full story on page 10. You can also read about how drones can become “technological predators” that can help producers spray more efficiency for pest control on page 14.
It may seem like we’re dealing with the same threats season after
“Our ecosystems are delicate, dependent, and unpredictable.”
“sesame seed” sized parasitoid wasp, emerged as a possible biocontrol candidate. The USDA-ARS scientists imported several strains of the samurai wasp to the U.S. to begin research. This was in 2005. In 2014, the project lead got a phone call that samurai wasps were spotted in Maryland. Genetic tests were done to make sure they weren’t wasps that escaped from the lab, and once they realized they weren’t, another fact became clearer. The samurai wasps
season, but pest migration, pesticide re-evaluations, weather changes, and technology innovation are going to continue to change our pest landscape. Will the pest threats covered in this issue matter in 10 years? Or will there be new pests lining the pages of our future issues? Coming into planting season, I hope this pest-themed issue helps you stay aware of what’s to come, and like the samurai wasp, I hope only beneficial surprises come your way. •
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*Actual technology may not be exactly as shown.
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Fruit and vegetable sales were up 1.3 per cent to $2.5 billion in 2019, mainly due to a three per cent increase in the value of vegetables, according to Statistics Canada’s fruit and vegetable production update for 2019.
The farm-gate value of vegetables grown in Canada rose for the ninth consecutive year. In contrast, the farm-gate value of fruits edged down 0.5 per cent. See By the Numbers below for a full breakdown.
The season was a mixed bag with highs and lows across the country. In Ontario, Canada’s largest asparagus-producing province, production increased 13.3 per cent to its highest level on record.
In British Columbia, production (-41.2 per cent) and farm-gate value (-37.9 per cent) of cranberries fell sharply in 2019, with farmers attributing the decline to a milder winter during which plants never entered full dormancy.
Potatoes, carrots, apples and strawberries are some of the most consumed produce by Canadians in the past 12 months, according to a consumer insight survey conducted by Leger 360. The most popular vegetables consumed by Canadians in the past 12 months are: potatoes (91 per cent), carrots (89), onions (87), lettuce (87), tomatoes (86), broccoli (82), cucumbers (80), peppers (79), celery (74) and beans (74).
The most popular fruits are apples (85 per cent), strawberries (82), grapes (79), blueberries (76), raspberries (69), melons (59), peaches (56), cherries (55), and pears (51).
There is a strong preference among Canadians for supporting local, especially in Atlantic Canada, Quebec, British Columbia and Ontario. In total, 85 per cent of Canadians prefer to buy
local vegetables and 84 per cent prefer to buy local fruits. Atlantic Canada showed the strongest preference with 92 per cent of survey participants preferring to buy local, while Saskatchewan and Manitoba showed the least with only 71 per cent preferring to buy local. The low percentages can be attributed to supply –there is less variety of locally grown produce in the Prairies.
BY THE NUMBERS – MORE FOR VEGETABLES
IN 2019
Total vegetable yields were up
While fruit yields were down from a year earlier from a year earlier
Overall, 90 per cent of Canadians have trust in their own, provincially-grown produce. A little less than that, 82 per cent, think the produce grown in their own province is top quality.
Regardless of origin, 75 per cent of respondents agree that price is the most important when purchasing produce. This is especially true when household income fell below $80,000.
{ They’re bugging out. }
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Researchers in North America and Europe share insights about SWD and new opportunities for control.
BY RONDA PAYNE
Fruit growers need no introduction to Spotted wing drosophila or SWD for short. The pest spread from its native home in southeast Asia to Europe and North America and has been making its presence known ever since. It’s not your average fruit fly with its persistence and desire for ripening fruit, versus other fruit flies that will only infest rotting fruit.
The pest issue began in Europe in 2008 when the pest came to southern France and Italy, and then made its way across Europe, according to Neal Ward, integrated pest management (IPM) and pollination specialist with Biobest NV of Belgium.
“It spread within a few years through all of Europe,” Ward says. “If there’s one thing to get from this, it’s that SWD is one of those pests where there’s no silver bullet. It’s a toolbox approach.”
SWD pressure in northern Europe is similar to Canadian berry-growing regions where the fruit fly is most prevalent from July to October. While prevention would be ideal, this isn’t the way European growers are dealing with SWD because they don’t have the tools they need yet. “What it boils down to is most growers use a reactive strategy,” Ward says.
Unfortunately, there are only three chemicals available for managing the pest in Europe and there have already been signs of pesticide resistance. Additionally, these chemicals are on emergency use and can be pulled at any time. On the flip side, Ward notes that this is an ideal opportunity for everyone in the industry to work together towards a solution. He says that academia, growers and agriculture companies are sharing knowledge to get ahead of SWD.
as possible and put traps in shady, humid areas around field perimeters to identify when pressure is mounting. The preferred trap seems to be the worst one available because it’s cheap, easy to use and uses good bait. Some growers monitor their fields year-round. “As soon as they see them in those perimeter traps, they have to make a decision of what to do,” he says. “They generally move on to checking for larvae in fruit and then may use one of the three sprays at that point.”
The advice for European growers is the same as what Canadian growers hear regularly: pick early, pick often, pick clean and maintain good field hygiene. Composting SWD-infested fruit isn’t advised as the amount of compost required to reduce the attractant levels is massive.
Other options being explored include the Trichopria wasp, which Ward says has its strengths and weaknesses. A European company is working on identifying ways to make the wasp a viable option. Ward cautions that there’s more to the wasp’s introduction process to be explored before it’s released because it can’t simply be released directly into the crop.
“There’s very little true open-field grown in northern Europe, even in southern Europe,” he says. “So we really need to be on top of our hygiene, so to speak. It’s pretty standard advice from an IPM person. Start clean. End clean.”
He adds that there is a need to keep the environment as dry
The Ganaspis wasp is another parasitoid wasp being assessed. It’s native to African regions and, Ward explains, this possible solution falls under the method of using an exotic species where there is an exotic pest.
“Nematodes have some potential, but what happens in a Petri dish and in a field are completely different,” he says. “Lure and kill techniques are definitely of interest whether that’s a chemical or a biopesticide. We can repel the SWD from the crop and push it into a trap.”
There is also the idea to deplete SWD through intercropping of non-host plants as well.
All these ideas could become possible solutions after field testing. “They are great ideas and they seem to work, but they need to be brought out into the field,” he notes. None of them ABOVE
Tree fruits likely to be hit hardest, scientists say.
BY PETER MITHAM
Situated a short distance off Highway 97 in a largely residential area of Kelowna, Day’s Century Growers is best known for its pears. The care and attention pears demand recently prompted upgrades to the operation’s packing line that improved the 122-year-old farm’s ability to care for fruit harvested from its 80acre orchard. But gentle handling won’t protect the Day family’s pears from the looming threat of brown marmorated stink bug (BMSB).
BMSB is an invasive species native to Asia that was first detected in North America near Allenstown, Pa. in 1998. Since then, the pest spread across the continent, being identified in southern Ontario and
the Niagara Peninsula in 2012 and the Fraser Valley in B.C. in 2015. It was identified in the Okanagan in 2016 and is now found from Osoyoos to Vernon, B.C., primarily in urban areas. Trapping first detected the pest in residential areas along the margins of the Day property.
BMSB has yet to become established in agricultural areas of the province, but entomologists say it’s only a matter of time. The pest has typically taken about 14 years to become an economic threat in areas of the U.S. where it’s been found. It is now the leading cause of damage to tree fruits in the northeastern U.S. and many fear it could become just as much a problem in the Okanagan.
“I realize the gravity of the potential increase of BMSB in our area,” says Kevin Day, who operates the Day’s Century Growers farm in partnership with his sister Karen and their families.
While the pest has just one lifecycle in B.C., it is shaping up to be a significant problem of late-season tree crops such as pears and hazelnuts. Surveys indicate noticeable increases in populations in late spring, when overwintering adults emerge, and at the end of the season when the next generation is preparing to overwinter. In between, nymphs usually stay away from most fruit crops and stick to hosts with tastier leaves. “Raspberries and blackberries are excellent hosts for the pest, and wild blackberry in particular can be a source of BMSB populations,” orchard extension specialist Nik Wiman of Oregon State University told growers attending the Pacific Agriculture Show in Abbotsford, B.C. at the end of January.
On the bright side, these crops typically ripen when the nymphs are feeding on leaves, meaning the fruit usually escapes damage. It also means cherries are less vulnerable to the pest than pears and hazelnuts, the two crops now facing increasing damage in Oregon.
“BMSB appears to be primarily an arboreal species; it really prefers trees,” Wiman says. “Although it can attack vegetables and other low-growing crops, trees are its favourite.” However, the pest’s establishment in residential areas of the Fraser Valley means growers are watching. “Damage has been found in these backyard gardens in berries and other crops that people are growing but we have not seen any commercial damage in berry fields yet,” says Allyson Mittelstaedt, soft fruits integrated pest management (IPM) coordinator with E.S. Cropconsult Ltd. in Delta, B.C.
Damage can take the form of sunken drupelets in raspberries and blackberries, or depressed areas of large fruit, sometimes with corking. Blanks have been noticed in hazelnuts. BMSB also secrete a pungent fluid when frightened that’s distinguished by the same molecule, (E)-2-decenal, that makes cilantro such a polarizing green. “Stink” bugs don’t get their name for nothing, Wiman notes.
A monitoring program was set up in 2019 in partnership with the province’s raspberry and blueberry councils to monitor for the pest. Six raspberry fields
and 10 blueberry fields were involved. E.S. Cropconsult placed traps at the end of rows and in hedgerows surrounding fields from June to August. Adults only showed up towards the end of the period, therefore trapping will take place from July to September this year to see what populations are like towards the end of the season.
The limited impact on berries is good news from an IPM point on view. Besides the selective appetite BMSB displays, Wiman notes that BMSB likely doesn’t have a chance to nibble while Spotted wing drosophila (SWD) remains the key pest of berries in the province.
Paul Abram, a research entomologist at the Agriculture and Agri-Food Canada ‘s (AAFC) Agassiz Research and Development Centre in southern B.C., says the low number of BMSB adults found in field crops indicates a very low risk at present. “They’re in some of the crop fields in low numbers, but there’s no evidence that they’re causing any kind of economic damage that would necessitate any level of control at this point,” he said. Abram isn’t resting easy, however. “This is still something to keep an eye on because based on our trapping data and other observations, it does seem like populations are increasing year to year,” he said. He noted that federal scientists have been monitoring pest populations at seven locations since 2017 and numbers have increased every year, rising five-fold between 2017 and 2018. “Our numbers in 2018 and 2019 were much higher, several times higher than in 2017, at the same sites,” he said. “This is the same trend we see across all of our long-term trapping sites.”
The best indicator to date of a crop’s vulnerability to the pest is its proximity to forested areas, which provide midseason foraging for the nymphs and allow populations to build until fruit ripens. “They’re highly mobile so they can move back and forth between these various habitats over the course of the season,” he said. By relocating fields, producers could conceivably mitigate the risk they face from the pest, but this isn’t always feasible.
Abrams is therefore investigating natural predators of the stink bug, a pest for which few chemical controls are available. Parisitoid wasps are the key natural predator of stink bugs, but native parasitoid wasps have not been cooperative in the fight against
the invasive species of the brown marmorated stink bug. However, samurai wasp, native to Asia, is seen as a promising candidate that could be introduced to fight BMSB in North America. Since it only targets BMSB, it poses no risk to native species or human health. In the United States, Science magazine profiled researchers at the U.S. Department of Agriculture’s (USDA) Agricultural Research Service in Newark, Del., who brought the samurai wasp back from Asia in 2005 to make sure that, if it was released, it wouldn’t upset the regional ecosystem. In 2014, the researchers were shocked when tests confirmed the presence of samurai wasps in Maryland. Like BMSB, the natural predators had immigrated on their own.
An application was made in 2018 to introduce the samurai wasp to Canada, but there has yet to be a decision. While the wasp has been sighted in Canada, new individuals can’t be introduced without government approval. However, if it does become established of its own accord, then permission to introduce it will no longer be required.
Researchers are working with 20 strains of the wasp in the meantime hoping to produce a strain that’s an effective predator. They’re also watching the local landscape, as the wasp has been sighted in Chilliwack as well as Ontario. Populations seem to be insignificant at the moment to declare the predatory bug established, and it’s even further from having an effect on local BMSB populations.
The research pleases Day, who has embraced the integrated pest management protocols that have been key to the reputation Okanagan fruit growers in international markets for their clean, high-quality fruit. “Integrated pest control has been the cornerstone of this farm’s success for 50 years,” he said. “I abhor the thought of disrupting that with some of the broad-spectrum chemicals that seem to be the only means to combat this pest at this time.”
How much of a threat BMSB proves to be is something researchers don’t know. While growers in the Okanagan are watching out for the pest, Lower Mainland growers may escape unscathed. This means the wasp may be of greater value in the Okanagan than the Fraser Valley. “We’re still in kind of a holding pattern where we don’t know what the future pest potential of the brown marmorated stink bug is going to be,” Abram said. •
ROSEMARIE SHEPHARD | Organic Council of Ontario
ABOVE
Chardonnay grapes at On Seven Estate Winery, a new organic vineyard in the Niagara region.
Although Canada’s share of global wine production is small, producers have found success through careful selection of the right grape varieties, and cultivation in regions with microclimates that are appropriate for viticulture. According to a 2019 report by Manitoba Agriculture (MA) and the Canada Organic Trade Association (COTA), Canada grew approximately 598 hectares of organic grapes in 2017, or about five per cent of Canada’s total grape crop. The largest regions for organic grape growing in Canada are in British Columbia, Ontario, Quebec, and Nova Scotia.
In Canada, organic wine is produced from certified organic grapes and regulated additives (e.g. non-genetically engineered yeasts). Under the Canada Organic Regime, the certification of organic wine is a two-step process: grape growing (viticulture) is certified as “crop production” and winemaking (i.e. fermentation, bottling, etc.) as “processing.”
Ann Sperling, director of winemaking and viticulture for Niagara’s Southbrook
Vineyards, told the Organic Council of Ontario in 2018 that the principles guiding viticulture certification are similar to other agricultural crops. In organic production, the use of artificial chemical fertilizers, pesticides, fungicides and herbicides is prohibited. The health of the soil and surrounding environment is key to growing quality grapes, and important for the long-term sustainability of the vineyard. There is a threeyear organic transition period, during which time the producer must follow organic practices, paperwork, and fees, but cannot yet use the Canada Organic Logo. This is also true for any other fruits used to make cider or wine. The three-year transition period can be a challenge as grapes are a perennial crop, and growers face the risk of lower yields while adjusting to using alternative pest and fungal control methods.
Many Canadian organic vineyards complement their organic methods with other sustainable practices. Southbrook Vineyards located in Niagara region of Ontario, for example, uses solar panels to meet most of its power needs, has
a forest biodiversity reserve covering 10 per cent of its land, and holds Demeter certification for biodynamic production. According to the Canadian Vintners Association, biodynamic production looks at the vineyard as a whole ecosystem and specifies that only plant- or animal-based products can be used as fertilizer. In accordance with this certification, Southbrook’s flock of over 85 grass and hay-fed sheep is shepherded in and around the vineyard, fertilizing and promoting biodiversity. Southbrook also enhances soil fertility using cover crops and manure.
Tawse Winery, located in the Niagara Escarpment, employs biodynamic farming as well, including chickens and sheep in the vineyard for fertilization, insect control, and vine pruning purposes. Ontario’s Frogpond Farm Organic Winery also includes animals in their wine production, keeping a variety of plants and animals on the farm to create a diverse and balanced ecosystem. They plant herbs and flowers between the rows of grapes to attract pollinators. Hidden Bench Estate Winery employs
geothermal energy to heat and cool their buildings and power their winemaking processes.
A common misconception about organic wine is that it is free of sulphites, a preservative used in winemaking for its antibacterial and antioxidant properties. Some individuals are sensitive to sulphites and develop allergies. While sulphites are sometimes viewed as “unnatural,” they are in fact a natural by-product of the fermentation process. In organic wines, added sulphites are limited, which is an added production challenge.
In spite of the challenges of organic production, a number of Canadian wineries have been producing highquality organic wines with great success. Organic wine is becoming increasingly popular, with global organic wine consumption doubling between 2012 to 2017. According to the COTA/MA report, the LCBO’s sales of organic wine reportedly doubled between 2010 and 2014, and Quebec’s SAQ reached organic alcohol sales of $97 million in 2017. •
Currently, there is no comprehensive listing of organic wineries in Canada. However, several regional organizations maintain organic producer listings where organic wineries can be found.
Certified Organic Associations of B.C.: certifiedorganic.bc.ca/.
Organic Alberta: map.organicalberta.org/
Organic Council of Ontario: directory.organiccouncil.ca/
Atlantic Canada Organic Regional Network: acornorganic.org/resources/organicdirectory
Portail Bio Quebec: portailbioquebec.info/
Preliminary results of field trials shows potential for pest control.
BY PETER MITHAM BELOW
The rotors of a drone drive the spray down into the canopy, preventing the foliage from acting as an umbrella and improving penetration and coverage.
Pest control using drones could take off if the results of trials being conducted on test plots in the Fraser Valley east of Vancouver continue to go well.
An initial trial of unmanned aerial vehicles to deliver Delegate WG and Malathion 85E to beds of leeks at the Agriculture and Agri-Food Canada (AAFC) Agassiz Research and Development Centre proved to be just as effective as a boom sprayer.
“What changes if you use a drone? That’s the question we’re trying to answer, essentially,” explains Markus Clodius, principal investigator with the Centre’s integrated pest management program. “We wanted to know what effect are we getting from this on the thrips population itself with the boom and with the drone: how did the two compare?”
The results from trials last year indicate that the drone did a slightly better job than a boom sprayer in controlling thrips, and did so using just 20 per cent of the volume as the boom sprayer. There was no phytotoxicity and overall crop damage during application was less.
“This was an encouraging initial result,” says Clodius, who plans to expand the trial this year to include larger plots and slower flight speeds to improve the consistency of application.
Clodius is conducting the long-term research project in partnership with Mark Vendrig of Precision Crop Tech Inc. in Abbotsford, B.C., which supplies drones and provides consulting services to the agriculture sector. The company
worked with about 40 farmers in B.C. last year, applying foliar sprays to about 45,000 acres of crops including berries, cherries, field vegetables and greenhouse crops. Vendrig has worked with growers in the U.S. and sees the potential for drones to make pesticide applications safer and more effective.
Drones promise safer delivery because application occurs at a distance from the applicator and lower volumes are typically used.
You get a bigger bang for the given volume of spray.”
The results from AAFC’s field trials helped further the research that he believes will open the door to the widespread use of the technology in Canada. Currently, the Pest Management Regulatory Agency (PMRA) considers drone applications an off-label use while the province limits licences for the aerial application of pesticides to pilots of fixed-wing aircraft and helicopters. “We’ve learned a lot as a result of this but we’ve also taken the drones to a completely different level of performance as a result,” Vendrig says. “[But] it’s not the perfect silver bullet that’s going to solve everyone’s problems.”
To date, drones have typically been used for low-altitude remote sensing to assess canopy development, foliar nutrients, irrigation stress, weed
pressure, and soil quality. AAFC research stations in Summerland, B.C., Brandon, Man. and Fredericton all have research programs that involve this kind of application. “There’s a lot of things that you can gather from an overflight with the right kind of camera, right kind of software,” Clodius says.
Drones have yet to be used widely for spraying agricultural chemicals, however. “There are things you can spray with it; Mark has been applying foliar nutrients to various crops with a drone, and in theory, you can whitewash the roof of a large greenhouse with one of these things,” Clodius starts. “However, pesticides are more tightly regulated.”
Australia uses drones for herbicides and in China and Japan, they’re used to apply pesticides to rice. In India, the country uses drones to kill mosquitoes and limit the spread of vector-borne diseases. The drones are helpful because the technology is able to access hard-to-reach locations. Vendrig has conducted fungicide trials in the U.S., where some jurisdictions allow pesticide application by drone. Despite the use in other countries, the practice has been off-label in Canada, and therefore off limits.
The genesis of the study of spray applications occurred when a Fraser Valley leek grower expressed interest following a demonstration at a field day in 2018. A year’s worth of preparation, including obtaining the necessary permits, led to the trial in the Agassiz Research and Development Centre last summer.
Drones promise safer delivery because application occurs at a distance from the applicator and lower volumes are typically used. The trial last year saw sprays applied
