| ||Why Should I Use a Seed Treatment?
Producers should consider seed treatments like an insurance policy for establishing the best crop possible given the growing conditions at the time. If conditions are good for crop establishment, seed treatments may not be needed. However, if growing conditions at establishment are not ideal the benefits of using a seed treatment will often more than pay for themselves. Good crop establishment is one of the most important stages in a crop’s development. Any negative impact at this stage will affect the stages after this and at the end, could impact yields. Seed treatments are a tool that producers can use to help them give a crop the opportunity to achieve the best yields possible.
What are the factors to consider when choosing a seed treatment?
What are the benefits of using the new seed treatments?
- Do you seed into cold soil under reduced tillage systems? Soil temperatures at seeding time are typically lower than with conventional systems. Soil temperatures around 5C which are often found at seeding time with reduced tillage systems, are warm enough for crop germination and emergence, but are not ideal. Colder soil delays crops establishment and gives seed and soil born diseases an opportunity to infect the plant. A seed treatment will protect the plant from many seed and possibly some soil born diseases in these slow growing conditions.
- Has your seed been tested for seed born diseases? Your seed may be infected with a disease that was in the crop it originated from. A good seed treatment will prevent most seed born diseases, like fusarium and smuts, from developing. If you bought pedigreed seed, the seed certificate of analysis should tell you if any diseased kernels were found and of which disease.
- Do you have insect pressure at seeding time historically and presently? In the case of canola, flea beetles can be a major problem at crop establishment. Although you can apply a foliar insecticide to control flea beetles, a seed treatment that contains an insecticide will protect the plant from insect damage from first emergence to several weeks after emergence.
- What is your crop rotation? Similar crop types grown in successive years promote disease inoculum build up in soil. For example the second year of back to back barley would have a high probability of developing a soil born disease. Some seed treatments can minimize the potential losses of a few of these soil born diseases, but it is still advisable to avoid growing the same crop type in successive years. By following a proper crop rotation and using a good quality seed treatment, you will not only protect the crop currently being grown but you will also avoid a build up of disease inoculum in the soil for the crop type in the future.
In recent years, the number of seed treatment products available to producers has increased greatly. The new products have several key benefits or advantages over the older products.
What types of diseases and insects do seed treatments control?
- One key benefit is lower dose and use rates. This decreases the amount of product that needs to be used and reduces environmental exposure to the user.
- Another benefit is that many new seed treatments contain several active ingredients with different modes of action. This has allowed manufacturers to develop seed treatments with higher efficacies and a broader range of diseases and insects that they control.
- Finally, a third benefit is that most of the new seed treatments are water based and are in ready to apply or RTA formulations. This allows the individual applying the seed treatment to handle the product with more ease and makes cleaning the treating equipment easier as well. In addition to the ease of use, the exposure of the applicator to the treatment is reduced as the older solvent based seed treatments required applicators to take precautions for avoid illness due to fumes.
- Over all, the new seed treatments are more effective, control a broader range of pests, and are much safer to use for both the applicator and the environment.
Generally, seed treatments contain a fungicide or a combination of several fungicides that will control a wide range of diseases. Common seed diseases in Alberta are various rots, bunts, smuts and blights. Most seed treatments have activity on some or all of these diseases but efficacy will vary depending on product, crop and use application rate. Always consult with the manufacturer’s product label crop suitability and application rates. Some seed treatments also contain an insecticide along with a fungicide that is most common with canola seed treatments.
Can seed treatments be used in combination with other inoculants?
Depending on the application, some seed treatments can be used with other seed treatment products. This would be most commonly used in pulse production where a fungicide seed treatment may be applied along with an inoculant product. Again, always check with the manufacturer’s label of both products to ensure that they are compatible and are registered uses.
Why do flea beetles still damage canola even with these new seed treatments?
With the removal of lindane from the Canadian market, new insecticides have been introduced as part of canola seed treatments. Lindane exhibited both repellent and control properties in that some flea beetles would avoid the plants treated with lindane. Pests that were not repelled were controlled by biting a treated plant. The new insecticides do not have this repellent property and need the flea beetle to bite the treated plant in order to ingest the insecticide. The result is that the canola seedlings will appear to have more damage than was the case with the lindane based seed treatments. However, manufacturer studies have shown that the these new insecticides have better control of flea beetles and have longer windows of efficacy. Producers should keep in mind that 25% or less damage to the canola cotyledons is below the economic threshold for flea beetles.
Why do the new seed treatment appear to have less coverage on my treated seed?
Because newer seed treatments have lower application rates, there is less physical product being applied to the seed. Even though the seed may not be colored as much as it was in the past, the products are still effective if applied properly. With these reduced application rates seed treater calibration is important as visual inspection of the seed will not ensure a proper application rate.
Are drip and gravity feed applicators good methods of applying the seed treatment?
No. Drip and gravity fed product applicators do not allow for accurate volume control or seed coverage. For gravity fed applicators, the volume rate will change as the container empties and will make it difficult to apply an accurate product rate. Drip applicators may somewhat control the volume of the product but do not allow for proper seed coverage. The seed treatment needs to be in contact with the seed and be of proper coverage to be effective.
What are the best methods of applying seed treatments in cereals and pulses?
Applying the seed treatment has two requirements, proper product volume and seed coverage. Before treating, knowing the capacity of the auger or conveyor is important. Knowing the capacity of the auger or conveyor will allow you to determine what volume of product will need to be applied to ensure the proper product rate is used. Determining the capacity of your auger or conveyor can be done by consulting the equipment manufacturer or by loading grain with the equipment and recording the length of time to load the volume of grain. By weighing this sample, determining the loading capacity can be calculated for any grain type. For seed coverage, using an applicator tip such as a nozzle of known volume output and pressure is needed. Spreading out the product flow across the seed being treated will allow for maximum coverage and efficacy. The most accurate seed treating applicators employ a positive pressure pumping system and nozzles which can be calibrated for any given seed treatment. These systems ensure proper product volume and seed coverage.
Why is seed treatment product rate and coverage important?
Seed treatment product rate and coverage is important for cost and efficacy. By over applying the product, the cost per treated seed unit will be higher yet providing no additional benefits and may cause harm to the seed. Not achieving proper seed coverage will affect efficacy and the benefit of the seed treatment will not be realized.
Prepared by Colin Bergstrom, Ag-Info Centre, Alberta Agriculture and Rural Development