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Diamonds Are Not a Farmer’s Best Friend

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The southern winds blew all spring and have left us wondering, “Did they bring the diamondback moths with them?”

What Are Diamondback Moths?

Diamondback moths are a pest on the Canadian Prairies, which migrate from the south to the north on the wind currents in the spring. They prefer brassica crops, which means on the prairies they feed mainly on canola. Diamondbacks can have up to 4 generations per year, so the damage period can depend on when they arrive, and how many generations there are.

The moths are 8-9 mm in length when resting, and they have 3 diamond-like markings on their back. The adult moths lay eggs on the leaf surfaces which can hatch to larvae in 4-8 days. Since the diamondback can have up to 4 generations per year, there can be all life stages in one field at the same time. 

Once the larvae hatch, they can feed up to 21 days. First on internal leaf tissue, then outer leaf tissue, flowers and buds. When the larvae reach maturity, they are a bright green worm around 12 mm (½”) long with a slight taper at each end. When the larval stage is complete, they pupate. This can last anywhere from 5 to 15 days. They then emerge as an adult moth, and start the whole process over again. The whole diamondback life cycle can vary from 21-51 days, depending on the environment and food conditions. 

What To Watch For

There are a few different monitoring techniques that can be used. The first would be pheromone traps, which are set out to predict early warnings of infestations. Unfortunately though, these traps are only an estimate or a predicting tool and regular monitoring in July and August is necessary. 

When it comes to scouting for these pests, you will be looking for the diamondbacks in the larval stage. It is important to identify them at this point in the life cycle as this is when they feed on the plant. Sweep nets can be utilized, but keep in mind there are no threshold numbers set for this method. Since diamondbacks can feed on all parts of the plant, the sweep net will not accurately collect the larvae in that testing area. If diamond back larvae are found in the sweep net, closer inspection is required of the crop. 

The best method of scouting is to visit 5-10 different areas in the field and remove plants in an area the size of a square foot. You will then lightly beat the plants on a clean surface, such as the hood of your truck or the tailgate. The larvae will fall off the plant, and you will be able to assess the populations. The action threshold is 20-30 larvae/ft2 or 2-3 larvae/plant. 

When you are assessing damage it is important to take into account the stage(s) of the larvae and the crop. Once leaf tissue begins to die off as the plant matures, the larvae will move up the plant and feed on pod and stem tissue.  This can quickly lower the yield potential of the crop.

How To Control Them

As with most pests, there are beneficial insects that can help naturally control populations. This can range from insects, to parasitoids, or fungi. The presence of these factors are important to take into account when deciding if you have reached the action threshold or not.

If the application of an insecticide is warranted, there are many options on the market. Insecticide would be applied if you have determined that your crop has reached the action threshold and needs another form of control to prevent further damage. There are different products available but it is important to be cautious of the preharvest interval and the impact on beneficial insects found in the field. 

 

If you need help monitoring for diamondbacks, or help deciding which control option would be the best fit for your operation, reach out to your SynergyAG agronomist or sales representative.

Niki Beingessner CCA, PAg

Sales Agronomist – Yorkton, SK

 

Sources:

Canola Council

Government of Saskatchewan

 

How To Keep Cutworms Away

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If you have noticed some bare spots out in your field, specifically on hilltops and in sandy areas, it would be a good idea to check in on your crop. Cutworms have been very hungry over the past few weeks and we have been finding them feeding in an array of different crops. 

The redbacked, pale western, darksided, army, and dingy cutworms are the five common species of cutworms that can be found, and cause economic damage in field crops on the prairies. Although some species are more common in certain areas, they all seem to be fairly widespread.

Where To Look

Most fields will have cutworms present in them, but not all will have concerning populations. It is important to scout, watch for any changes, and also monitor for the economic threshold. We usually begin by scouting any hilltops or areas in the field with lighter soil. Cutworms are known to prefer these areas because they are warmer and easier for them to tunnel around in. In these areas of the field, we check for spaces within the row as well as wilted or dead plants in those spaces. This is a telltale sign there are usually cutworms present, as they prefer to move from plant to plant within the row. You will also need to monitor those areas for germination issues or seeding misses, which can also be at fault for the spaces within the row.

Within these gaps in the row, you will need to carefully brush away the soil and locate the pest. Cutworms predominantly feed at night above the ground, and will shelter underground during the day. They are usually just below the soil or trash within the row, but can also hide in the soil between the rows as well. It requires boots on the ground scouting, and can be a very tedious process. 

If you check a few spots in the field and cutworm numbers are high, it is important to check what the threshold is for that crop, and determine if it is time for a control option. This will involve checking many different areas in the field to determine whether spot spraying is an option, or if the whole field needs to get sprayed. 

How To Control or Manage

On canola seed, you can add a group 28 insecticide treatment like Lumiderm or Fortenza, which will kill any cutworms that feed on the plant after they have germinated. This requires there to be some damage to your crop, but it is an effective option for cutworm control. 

Pulses and cereals are more challenging. Corteva has just released a new seed treatment called Lumivia CPL that is a group 28 insecticide, and it can be added to your regular seed treatment to help your crop defend itself against cutworms. Like the canola seed treatments, it also requires feeding and ingestion for control.

If you have not used any of the seed treatment products above, there are also in-crop insecticide options such as Matador and Pounce. Both will give you a similar level of residual activity and will effectively control cutworm infestations. 

Tips For Future Planning

Cutworm populations have increased over the last few years and don’t seem to be declining. If you have had cutworm infestations in the past, it is important to take that into consideration for the future. Take note of which fields had higher numbers, and monitor those fields closely in years to come. Also, consider on-seed control options mentioned above for fields that are of concern.

If you’d like one of our Agronomists to scout your fields for cutworms and other pests, find the nearest SynergyAG retail location to you!

 

Niki Beingessner CCA, PAg

Sales Agronomist – Yorkton

Flea Beetles – Chewing Their Way Into June

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As many people find themselves finishing up the seeding season, we also find ourselves at the beginning stages of the bug season. If you have been out and about in your fields you have probably noticed small black bugs that are the size of a pin head bouncing around. 

The striped and crucifer flea beetles are the two common species that feed on canola in the Canadian prairies. Hop flea beetles can also be found, but occur in low numbers throughout the prairies. All three species can vary in the way they look, how they feed, and when they emerge. 

When To Look For Them

Flea beetles emerge in early Spring, and can cause damage to your canola crop from emergence, up until the 3-4 leaf stage. They aren’t picky eaters, and are known to feed on the cotyledons, leaves, stems, roots or any fleshy tissue on the plant. Sunny, warm and dry weather is preferred by the beetles, but less ideal conditions don’t seem to slow them down either. They are known to increase below ground and underside of leaf feeding during the less than ideal conditions.

How To Manage Them

It is important to assess where the bugs are feeding and how much of it there is. Action threshold levels are when average leaf area loss is more than 25%, and it is considered economically beneficial to spray insecticide when the leaf area loss is above 50%. There are no established threshold levels for stem feeding, which is why it is so important to assess where the feeding is taking place. If the flea beetles are actively feeding on leaf tissue, stem tissue and/or the growing point, the action level might be lower. 

There are different control options and management practices to help mitigate the damage these guys can have on your canola crop. Seed treatment options like Prosper Evergol and Helix Vibrance are standard on your canola seed to protect against flea beetles, but you can enhance your protection by adding Lumiderm on your seed when you order it. There are also in-crop insecticide control options to cover you off if populations rise and leaf damage is above threshold levels. Lastly, there are cultural control methods such as seeding early to get crop establishment before the emergence of the flea beetles, allowing a higher tolerance to injury. The second practice is increasing your seeding rate, this can help you reduce the impact of the flea beetle damage by spreading it out over more plants allowing for easier recovery from the stress event. 

Don’t Fear Though

The sight of these pesky little bugs probably have you wondering a few different things. Such as, why your seed treatment isn’t working. The truth is, it is working. But, with the newer chemistries, the flea beetles have to feed on the plant to ingest the insecticide for it to work. Whereas older seed treatments were used as more of a deterrent or repellent. Also, seed treatments only give a 28-35 day protection window after the crop is seeded, in cooler, dry weather the crop could be slower growing and not past the 3-4 leaf stage so it is at risk for flea beetle damage. 

Contact our SynergyAG Agronomists and they can help you determine which is the right course of action against your flea beetles! 

 

Niki Beingessner CCA, PAg

Sales Agronomist – Yorkton