OTTAWA - The soybean aphid, a tiny sap-sucking insect that can cause stunting, smaller seeds, puckered yellow leaves and reduced pod set, is a big problem in Quebec and Ontario that is leaving researchers with more questions than answers.

While the soybean aphid is making researchers lose sleep, producers from Ontario and Quebec heard that they are learning more and more about the pest during Agriculture and Agri-Food Canada’s Crop Day at the Eastern Cereal and Oilseed Research Centre (ECORC) at the Central Experimental Farm on July 8. This year’s event focused on the war against pests.

In the morning, participants heard six presentations touching on pest control for oats, soybeans and corn, weed control and fungicide application. In the afternoon, they were joined by members of the Canadian Seed Growers Association, who visited the Farm as part of their 100th anniversary, as they toured the Farm’s oat, wheat, barley and corn fields and heard from breeders and pathologists.

The soybean aphid was a hot topic and was seen from the perspective of researchers in Quebec and Ontario.

Michèle Roy, a research scientist in entomology at the Direction de l’innovation scientifique et technologique (DIST) in Sainte-Foy, PQ, spoke about the integrated control of pests in the province, which became a big issue around 2001 with an outbreak of armyworm.

Since then, concern about the soybean aphid has been growing.

Quebec’s soybean crops cover 150,000 hectares and are a major cash crop. There is a high demand for soybeans, and Roy expects that "with the enlargement of fields, the soybean aphid might change soy practices."

At the end of 2001, Roy and her research team decided to create a control program for the soybean aphid in Quebec.

"It’s a great concern for us," she said. "The soybean aphid is a priority. We don’t even know if it migrates or stays with us during the winters."

In 2002, they began a surveillance program looking at the trajectories of air masses because they thought the aphids may have come with the air mass, and they studied the aphid’s natural predators.

"There are a lot of them because soy isn’t treated," she said. "Last year there were so many predators that we asked producers not to add any treatment."

The aphid’s predators include ladybird beetles, minute pirate bugs and lacewings.

"We dealt with ladybird beetles to see if they could help us with later infestations," Roy said. "The Asian ladybird beetle better performs in the lab, has a very high fecundity rate and is very active on the aphid."

Roy said a lot of soy is produced in southwest Quebec near rivers and urban populations, so they want to limit the use of pesticides.

"This is our current research project dealing with natural predators in the biological fight against pests," she said. "Low-impact, organic soy is a very good cash crop for farmers so that is why we’re looking at alternative methods."

ECORC biodiversity (entomology) and integrated pest management research scientist Dr. Peter Mason then spoke about Ontario’s actions to fight the soybean aphid.

Mason, Dave Hunt and Rob Footit are working on a project to establish the status of the aphid in Ontario and the potential distribution and infestation levels that could occur.

They’ve found that the aphid occurs naturally in southeast Asia and came to Canada from the Midwest United States.

Mason said they are not sure exactly where in Asia the aphid population comes from, but their research indicates it was probably a single immigration.

They do know the aphid overwinters in the United States, and they speculate that it comes in on the backward wind trajectories.

In mid-April, Mason and his team set up 30 or 40 sites in Ontario and Quebec to study the wind trajectories.

They also studied the date and location of the aphid’s first appearance the past few years to help determine the source of the annual infestations.

In 2001, the aphid was first detected on June 16 in Chatham, and the next year, it was discovered on July 13 near St. Thomas. In 2003, the first aphids were found between June 8 and 14 near Mitchell’s Bay.

"It’s very likely that these populations were brought from the Midwest and dumped into Ontario, then later on they moved to Quebec," Mason said. "In 2003, winds passed over the Midwest and picked up populations and brought us a present, no checks at the border."

Environmental factors could also play a role in the infestations.

"A lack of precipitation seems to contribute to higher aphid numbers," Mason said.

The soybean aphid has an alternating life cycle, and its summer host is the soybean.

Mason and his partners are looking at the overwintering potential of the aphid, and they have found that buckthorn, which is found in all of Ontario’s counties except Essex and Kent, is a very important host.

"There are actually two or three generations produced on buckthorn," Mason said.

Mason has also been busy studying the use of biological controls to manage the aphid.

He hopes to identify the potential of native parasitoids, predators and pathogens to control the aphid and determine the likelihood of commercially developing promising pathogens.

"We might look at introducing enemies like the wasp," Mason said. "The US is already doing this."

He has found that the aphid’s natural enemy populations seemed to increase at the same time as aphid populations rose, and, like Roy, he has focused on the Asian ladbybird beetle.

"Ladybird beetles are very important," Mason said. "The Asian ladybird beetle is wonderful for soybean aphid and growers, but there are bad things that occur. Because it’s such a generalized feeder, it causes problems because it doesn’t just eat insects."

Despite its potential to create more problems, Mason says this predator is "probably the best thing we have to respond to the aphid."