Editor’s Note: This article was provided by Bayer CropScience Canada.
With the 2014 growing season fast approaching, what’s on the minds of Canadian potato growers? A few were asked that very question and almost all said their biggest concern this spring was considering seed-piece treatment options and best practices for pest management.
Andrew Dornan, field development representative for horticulture with Bayer CropScience Canada, addresses the most common questions from these growers, and others being heard in the fields, to help potato crops get off to a strong start.
Question: The weather was favourable last year, but we aren’t always that lucky. What soil conditions are optimal for planting treated potato seed-pieces? And in what conditions are dust or liquid seed-piece treatments better?
Dornan: Every farmer knows weather can be unpredictable. We cannot control the conditions we’ll see this spring. However, it is recommended that treated potato seed-pieces be planted into adequate soil conditions regardless of whether you are using a dust or liquid seed treatment. Adequate soil conditions mean that the soil temperature should be between 10 C and 12.8 C, with sufficient soil moisture. Avoid planting warm seed into cool soils and try to have the seed temperature as close as possible to the soil temperature.
Question: If the seeded portion of the crop has sprouted, should you still apply a liquid seed-piece treatment?
Dornan: We do not recommend applying a seed-piece treatment on excessively sprouted seed-pieces. It may result in reduced germination, vigour and/or yield. Seed-pieces should be treated immediately after cutting.
Question: There are liquid seed-piece treatments available with or without colourants. How do I choose the best one for my operation?
Dornan: First, make sure to read the label and choose the product that will be most effective at controlling the insect and disease pressures in your field. The benefits of using a coloured seed treatment are numerous:
- Coloured seed treatments allow growers to easily see if the product has been properly applied to the seed to maximize protection and to ensure accurate and continuous treating
- They allow for easy cleaning, as those treating the seed can clearly detect the product on equipment and protective gear
- In the event of a product spill, it’s easy to ensure you have cleaned it up sufficiently
Question: We’re seeing beetle resistance in our field; what products can be used alongside seed treatments to control them?
Dornan: Colorado potato beetles have been a challenge for the potato industry for decades, causing crop losses and increased production costs. They’ve become increasingly difficult to control because they’re developing resistance to commonly used insecticides. It’s recommended that growers use alternative modes of action in their seed-piece treatment and foliar insecticide program. For example, when using Titan Emesto, do not apply another Group 4 insecticide as a foliar application. Instead consider a product like Delegate or Success, both Group 5 insecticides. Rotating crops and planting potatoes several hundred meters from previously infested fields can also help to control infestations and limit resistance.
Question: In Prince Edward Island, our biggest pest problem is wireworms. What is the best way to control them?
Dornan: Wireworms are a becoming a problem for potato growers across the country, but particularly in P.E.I. Unfortunately there are few available products to control them. We recommend using a seed-piece insecticide treatment registered to suppress wireworm damage and follow up with an in-furrow application of a registered product when damage is expected to be severe. Rotating your crop to less preferred host crops (i.e. alfalfa) can also help to reduce populations.
Question: If I use multiple herbicides with the same mode of action, will this cause a problem for my soil? Or will the product continue to be effective?
Dornan: Your soil will be fine, but using the same mode of action repeatedly could select for resistant weeds that will rob your crop of vital resources. In the long run, resistant weeds will set seed, multiply and spread throughout a field. We recommend rotating modes of action and/or using multiple modes of action to effectively manage herbicide resistance. Crop rotation is also key in managing the potential for developing resistant weed populations and also allows the rotation of herbicide chemistries.
Question: With the rise of herbicide resistance, are there any new herbicides being made available in the near future?
Dornan: At the moment, there are few new modes of action on the horizon. It is therefore important for growers to continue to rotate their crops and herbicides to reduce the potential for resistance. For more tips on herbicide resistance, you can visit the website mixitup.ca.
Question: What are the best ways to prevent early and late blight?
Dornan: Late blight is a devastating disease that spreads very quickly once established. It is important for growers to protect their crops from it by following a few tips. First, it is essential to choose healthy seed and maintain good agronomic practices. You need to diligently monitor for early symptoms and apply fungicides preventatively. Finally, if you see a diseased plant, you must get rid of it quickly, as well as the plants in the vicinity of the infected plant. Reason fungicide is an excellent foliar fungicide for control of late blight and has recently been registered as a seed-piece treatment to protect against seed-borne late blight. Early blight is a leaf spot disease that indirectly reduces yield due to defoliation. Similar to late blight, you also need to monitor for early symptoms and apply fungicides preventatively. Recently, the disease that had traditionally been called early blight has often been determined to be a complex of diseases, which includes both early blight and brown spot. These diseases are now referred to as the leaf spot complex. Not all products that control early blight are also labelled to control brown spot. Luna Tranquility is a new dual mode of action product that provides protection against both early blight, as well as brown spot for unparalleled control of the leaf spot complex.
Question: White mold was a concern last year; how should growers prepare to handle it this year?
Dornan: White mold develops during wet seasons or under excessive irrigation. To handle it effectively, growers need to adapt their cultural practices and use an adequate foliar fungicide if required. If you had white mold last year, rotate your crops with non-susceptible hosts like corn (if applicable) or small grains. Since white mold can survive for several years in the soil, rotating non-susceptible host crops will disrupt the fungus lifecycle.
To prevent the development of white mold, it is important to maintain irrigation practices that provide adequate moisture to the crop, but also allow the field soil surface to dry. Luna Tranquility is a new dual mode of action product that also provides protection against white mold.
