Insect Pests
Soybean aphids have become well established throughout the northern Midwest United States and the provinces of Ontario and Quebec, causing significant damage in some years.

Because of the potential for ongoing problems from this yield robber in the future, there have been significant funding efforts from research programs: One management strategy has been to develop soybean varieties that are resistant to soybean aphids.

“The checkoff in Ohio as well as the North Central region states have put in a lot of investment in developing soybean plants that are resistant to the aphids, but now we have aphids that have overcome that resistance,” said Andy Michel, field crops entomologist at Ohio State University.

To address this challenge, researchers took on the extensive process of sequencing the entire soybean aphid genome to help develop strategies that prevent the spread and increase of aphids capable of breaking aphid resistance. Michel led the effort.

“My laboratory at Ohio State focuses on understanding how soybean aphids are able to overcome aphid resistance in soybean. Through this research, we hope to develop strategies that prevent the spread and increase of aphids capable of breaking aphid resistance. In the course of generating DNA sequences…we were able to sequence the entire soybean aphid genome,” he said. “We now have a really good roadmap for the soybean aphid and understanding all of the genes that are involved that make the aphid such a bad pest for soybean farmers in the north central region.”

The soybean aphid is now the fourth aphid species with a completely described genome and this new information will be a valuable tool moving forward with soybean aphid management. | READ MORE
“The pea leaf weevil has been a traditional pest for many years, and there is a lot of these pests in Canada,” says Gadi V.P. Reddy, entomologist of Montana State University’s Western Triangle Agricultural Research Center (WTARC). “The pea leaf weevil spread across the pulse growing regions in 2012, increasing problems caused by the pest.”

Reddy spoke at WTARC field days about his pheromone research project. Reddy has grant funding under the Montana Specialty Block Grant program, in cooperation with the Montana Department of Agriculture and USDA-National Institute of Food and Agriculture (NIFA), for the pea leaf weevil pheromone project to attract the pea leaf weevil.

There are two generations of pea leaf weevil per year, but the second generation of adults don’t cause damage like the first generation. During winter, the weevil hibernates under debris leaves and emerges in the spring, usually around May. When the pest emerges in spring, the adults feed on pollen and nectar on leaves; then they mate and the females lay eggs on the seedlings of peas and lentils that emerge as larvae. The larvae or grubs burrow deep in the soil and feed on roots and root nodules, causing damage. Plants fix less or no nitrogen when the roots are damaged, and sometimes the plant itself dies.

Reddy experimented using baited aggregation pheromone traps in the field to help monitor and mass trap weevil populations. He found that the pitfall traps worked the best at catching pea leaf weevils. These traps are a container that is sunk into the ground so that its rim is flush with the soil surface. Insects simply fall into the trap. Reddy used a liquid aggregation pheromone to lure them.

Another pheromone lure type is a bubble wrap, placed in pea or lentil fields.

In these traps, growers use a small quantity of soap or detergent water so that the trapped weevil gets killed.

“We found a lot of pea leaf weevils in our pheromone traps in 2016. Next summer, we will determine how many pheromone-baited traps we need per acre to trap the weevils,” Reddy says.

In addition, WTARC will be developing biodegradable pheromone lures so that growers won’t have to take them out of the field after each season.

Reddy is also looking at bio-based insecticides to control pea leaf weevils.
The wheat midge forecast for 2017 shows an overall lower level of wheat midge across Alberta. There has been a slight bounce back from the collapse of the extreme populations in the eastern Peace region. Although wheat midge has not followed the forecasts very well in the Peace region, it's important to note that there are likely sufficient populations of midge in the eastern Peace to fuel a resurgence if conditions are in the insects favor (specifically delayed crops and higher than normal rainfall).

Central Alberta has some areas of east of Edmonton with high numbers of wheat midge. The population has remained low in much of southern Alberta with the exception of some irrigated fields. Producers should pay attention to midge downgrading in their wheat samples and use this as a further indication of midge risk in their fields.

Over the past several years the field to field variation has been very considerable throughout the province, especially in those areas with higher counts. Individual fields throughout Alberta may still have economic levels of midge. Each producer also needs to assess their risk based on indicators specific to their farm. | READ MORE

A new study is helping Quebec researchers understand how to better control soybean aphid in the province.
Sometimes it’s a good thing to come second. Dry beans are the second choice for western bean cutworm moths looking for a place to lay their eggs. They prefer corn at the pre-tassel stage, but if they can’t find that, then they’ll go to dry bean fields. So far in Ontario, this invasive pest is causing the biggest problems in corn, but western bean cutworm has the potential to be a serious pest in dry beans, as Michigan growers have found.
Strip cropping is a method of cultivation in which a variety of crops are sown in alternating strips in a single field. It is a type of intercropping that involves planting crops in distinct rows that can be separately managed.
Seed corn maggots took a costly bite out of many south-central Ontario soybean fields this spring. In Wellington County, some fields were decimated to the point of needing complete replanting. While seed corn maggots are not a new problem, their unpredictable occurrence, limited control options and sometimes devastating consequences make them a major and costly headache for producers.

“Are seed corn maggots the kind of pest that wipes out 50 per cent of Ontario’s soybean acreage? No. The overall per cent is relatively small. But, if you are a grower that gets hit with maggots, it’s very significant and very costly for you,” says Horst Bohner, soybean specialist with the Ontario Ministry of Agriculture, Food and Rural Affairs.

Seed corn maggots are small, light yellow maggots that feed on germinating soybean and corn seeds. Because adult flies will only lay eggs in moist, rotting vegetation and larvae need time to do maximum feeding, seed corn maggots are most damaging in cool, wet, slow springs.

Most outbreaks tend to be fairly regional. That said, predicting an outbreak remains extremely difficult.

“The biggest problem with predicting when seed corn maggots will be a problem is that we don’t have a handle on when there will be large numbers of adults. We understand that if seed comes out of ground slowly there is more time for larvae to feed. But why there were a large number of females at one time in a specific region this year, I don’t think anyone knows that. So many of these insects just cycle,” Bohner says.

Once seed corn maggots hit a crop, there is not much a farmer can do but wait to assess damage. Seed corn maggots are difficult to counter because it is virtually impossible to scout for adult flies, and there are no post-seeding pesticide treatment options.

While seed treatments tend to be effective against the larvae, gaining approval for their use can prove to be a chicken or egg scenario: to be approved, one must prove damage has caused a loss of 30 per cent or more of the stand. However, once need is identified it is much too late to counter the maggots and the benefits of a neonicotinoid treatment can only be seen in a replant.

One maggot countermeasure every producer should follow is prioritizing speedy germination and seedling emergence, Bohner says. “Think about proper planting depth, good seeding timing, adequate nutrition and disease management, good residue control. You want to do everything you can to get that seed out of the ground as fast as possible.”

Like many flies, adult seed corn flies are attracted to the odour of decay. Seed corn flies lay their eggs in freshly tilled soil, decaying crop residues, and manured fields. As such, farmers concerned about seed corn maggot infestation may want to consider no-till management. At the very least, farmers should seriously consider opting not to till under cover crops or manure within three weeks prior to seeding.

Farmers who suspect seed corn maggot infestation in their fields should look for widespread and fairly consistent damage across the field, rather than patchy or localized damage. Then, dig up seed to look for obvious physical damage and/or the telltale yellow maggots.

Because the seed corn maggot’s entire lifecycle can occur in as little as three weeks, be aware that a new generation of maggots may be primed and waiting for a second planting of seeds. If seed corn maggots are verified in a field and damage warrants a replanting, consider planting insecticide-treated seed.

It is very difficult to estimate the cost of damage inflicted by seed corn maggots on Ontario fields.

“What typically happens in Ontario is that we have considerable acreage that needs to be reseeded each year, but it’s hard to always know why it needs reseeding. It could be soil borne diseases, insects, cold stress, soil crusting. More often than not, it’s a combination of factors. Seed corn maggots are just part of the overall picture. Replanting costs money and reduces yield potential, but calculating exactly how much of that is due to seed corn maggot is almost impossible,” Bohner says.

“But, I’ll tell you this,” he adds. “Seed corn maggots are frustrating and they are costly. I’ve been doing soybean trials for 15 years. This year, we had a large experiment completely wiped out because of seed corn maggots. So I do know exactly what the farmer goes through when he sees his hard work destroyed by a hard-to-manage pest like seed corn maggot.”
John Gavloski, entomologist with Manitoba Agriculture, has compiled a summary of insects on crops in Manitoba in 2016. The report is based partially on observation by Gavloski and his summer assistant, and a large part is based on observations and reports from agronomists, farmers, farm production extension specialists, extension coordinators, and others who contributed information over the season. | READ MORE
Entomologists at Agriculture and Agri-Food Canada (AAFC) study many aspects of the insects that make their home in crops and nearby land. One of those aspects is how the "good" insects contribute to the producers' bottom line in terms of the pest control services they provide. Economists estimate that for every $1 invested in Integrated Pest Management research, the industry gets back about $15 in benefits. This new video provides a brief look at some of the work AAFC entomologists do in Saskatchewan.
Our enemy’s enemy is our friend. That’s the idea behind a calculator being developed to help Prairie cereal growers make decisions on whether to apply insecticides. In this case, our enemies are the various aphid species that infest cereal crops. If aphid populations are high during a sensitive crop stage, these delicate little insects can make a big dent in cereal yields. The aphids’ enemies include an array of insects that are able to chomp down, suck dry or otherwise destroy impressive numbers of aphids.
Swede midge first appeared in canola in Ontario in 2003, and recent extreme populations in northeastern Ontario resulted in the Ontario Canola Growers’ Association (OCGA) strongly recommending in 2015 that producers avoid growing canola for three years across the New Liskeard area in an attempt to suppress swede midge populations.
If parasites want to get to soybeans, they'll have to go through Kansas State University researchers first.
DuPont Pioneer researchers have discovered a protein from a non-Bacillus thuringiensis (Bt) bacterium source that exhibits promise as an alternative means for controlling corn rootworm in North America and Europe. Science Magazine published the finding this week.

“This research represents a breakthrough for addressing a major challenge in agriculture,” said Neal Gutterson, vice-president of research and development for DuPont Pioneer, in a press release. “We have discovered a non-Bt protein that demonstrates insecticidal control of western corn rootworm with a new and different mode of action than Bt proteins currently used in transgenic products. This protein could be a critical component for managing corn rootworm disease in future corn seed product offerings. The work also suggests that bacteria other than Bt are alternative sources of insecticidal proteins for insect control trait development.”

An extremely destructive corn pest, corn rootworm larvae and adults can cause significant economic loss for growers. The current biotech approach for insect control sources proteins from Bt soil bacteria. Field-evolved insect resistance to certain Bt proteins has been observed in some geographies.

Another Pioneer study related to non-Bt insect control, recently published in Scientific Reports, shows how RNA interference (RNAi) can be applied to control corn rootworm feeding damage.

RNAi is a biologically occurring process that happens in the cells of plants, animals and people. By employing the RNAi process, a plant can protect itself by carrying instructions that precisely target specific proteins in pests.
In late July, Alberta Agriculture and Forestry (AF) staff surveyed 42 canola sites in central Alberta and detected very low density swede midge larvae.
Integrated pest management (IPM) is simply the process of integrating the use of pesticides with cultural, mechanical and biological controls in a planned and systematic approach to control weeds, insects and diseases.

Ideally, we don’t want to kill plants, animals, insects or other organisms unless they are causing or likely to cause crop damage or loss. But cropping practices such as soil tillage, use of certain crop rotations or use of pesticides can inadvertently affect non-target organisms.

Most pest control programs focus on the use of chemical pesticides. Typically, pests are identified in the field to estimate their potential population and damage potential, then a decision on type of pesticide, time of application and application rate is made. Unfortunately, this commonly used approach neglects to anticipate future effects due to use of the pesticide. Pest control chemicals often kill non-target organisms. For example, an insecticide application will kill non-target insects, many of which are beneficial. Destroying the predators and parasites of crop pests can cause a rapid rebounding of the crop pest in numbers even greater than before application. Repeated use of an insecticide year after year can lead to development of insect tolerance or resistance to the insecticide.

Fungicide application can effectively aid in controlling fungal crop diseases. But, repeated use of a fungicide will lead to adaption and tolerance to the fungicide, causing it to become less effective. Repeated applications of fungicides and insecticides over years may adversely affect soil microbial populations. Promoters of pesticides rarely mention this, but in the long-term, repeated applications could have significant effects on native soil organisms, which are critically important for soil health.

Herbicides have become very important for weed control. Frequent and repeated use of the same herbicide groups, however, has gradually resulted in development of herbicide-resistant weeds – a very serious problem for many farmers across the Prairies.  

We must be very mindful and carefully consider both the positive and negative impacts of every practice we use to achieve optimum crop yields. Farmers must constantly try to balance short-term benefits to increase crop yield with long-term impacts on future crop production. The goal of IPM is to try to combine chemical, cultural, mechanical and biological controls together in a proactive crop production system to try to enhance long-term sustainable crop production.  

The first step in IPM is to only use preventive treatments when actually needed. Often, chemical treatments are used on a scheduled basis. For example, spraying canola for cabbage seed pod weevils is often done at a scheduled time, rather than scouting, sweeping and monitoring fields to decide if and when to spray. Scouting and monitoring is time consuming, but chemical treatments are only applied in response to identified need if the insect is at a critical threshold level and chemical application is carefully selected for least disruption of the natural environment.
IPM does require more careful pest monitoring. A farmer must constantly monitor fields, develop action plans and analyze the results of treatments.

Ideally, a farmer needs to understand why various pests are present in fields. For example, how were new weed types introduced onto the farm? How could this be avoided in the future? How can new weeds be managed? For some diseases, could cultural controls such as using a more diverse crop rotation to break disease cycles reduce the presence of the problem? For some diseases and insect pests, could the use of a tolerant or resistant crop variety be an option? To consider control options, farmers must develop a very good knowledge of the various pests in their region and understand the biology and life cycle of each pest.  Awareness of changing pest trends is also important. To do this, careful recording of information for each field and crop is required every year on your farm.  

Detailed field record keeping is time consuming, but over time this practice can provide valuable information on changing trends on your farm. Pest occurrences in a field or on the farm often occur due to events earlier in the season or the previous year. Most farms are large and the combination of numerous fields, crops, events and treatments are often complex and difficult to remember without the help of well-organized, detailed field records. Using an electronic record-keeping system can be important for analyzing your IPM program.
There are many IPM practices a farmer can consider. I have summarized some important factors.

Seed and seeding
There is no substitute for excellent seed.
  • Have you selected the best regionally adapted crop variety for your area? Disease resistance is constantly breaking down in older varieties, but breeding advances are constantly improving disease resistance and agronomic characteristics. Be sure to constantly review new varieties available that are well suited for your region and suit your growing requirements.
  • Is your seed source free of weed seeds? A number of plant diseases are present on seed (seed-borne diseases). Be sure to use seed that is disease free and weed free. Ensuring seed is cleaned and tested for disease is very important. Using certified seed is a very good practice to consider.
  • Select the most disease-resistant varieties for the diseases present in your area. This will help reduce the need for fungicides.
  • Treat seed with the fungicide or fungicide/insecticide combinations for cost-effective control of pests present in your fields.  

Crop rotations
Wisely rotating crops is extremely important for reducing pest problems.
  • Rotating crops will help control less mobile insects.
  • Rotating crops will reduce the presence of residue-borne fungal and bacterial diseases. Having a break of several years between crops susceptible to the same disease will reduce disease potential.
  • Long-term crop rotations that include annual crops and perennial forage crops in the rotation are ideal. Forages are excellent for lowering disease risk of annual crops in a long-term rotation, and also reduce the presence of weeds. Forage crops are also very helpful to improve soil quality and build soil organic matter.
  • Shorter term crop rotations using annual crops should include at least two or three crop types, such as cereal, oilseed and pulse crops. Ideally, don’t grow the same crop more than once every four years. Don’t grow different crops susceptible to the same disease back to back. Sequence crops to your advantage. After growing a nitrogen-fixing crop such as pea, grow spring or durum wheat to take advantage of nitrogen release from pea residue to increase grain protein. A good diverse rotation can interrupt weed, disease and insect cycles. Rotating crops makes it easier for a farmer to rotate different herbicide groups to reduce the potential of developing herbicide-resistant weeds.
  • Alternating winter wheat and spring wheat, with different life cycles, in a diverse crop rotation helps to disrupt the life cycle of weeds to control weed problems.
Conventional versus zero tillage
Reduced and zero tillage across Western Canada has contributed to soil moisture conservation, reduced fuel costs, reduced wind and water erosion, and greatly improved soil quality and soil health. Zero tillage also means weed seeds are not incorporated into soil, which is helpful in terms of cultural weed control. But in situations when considerable disease infected crop residue remains on the soil surface, the use of tillage to bury diseased residue will promote residue decay to prevent infecting growing plants. There are times when tillage may be appropriate to assist with disease control, but always keep in mind the importance of soil conservation.

Sanitation is key for pest control. Practice excellent equipment sanitation by cleaning farm equipment to prevent spread of weed seeds and disease organisms from field to field. Insist custom application equipment, industrial equipment and vehicles or ATV’s of visitors that enter your farmland be thoroughly cleaned to prevent importing weed seeds or disease organisms onto your land.

This article just scratches the surface of the potential for IPM.

Do your own research to understand as much as possible about the pests on your farm and the various control options.
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