Q: How can I decrease the risk of early-season disease in cereal crops?
A: Seeding can be a stressful time of year for many growers. It is the most important operation on any farm, as it can dictate how the entire year will turn out. It’s important for growers to make sound agronomic decisions at the time of seeding to ensure their crop has the best start possible.
For cereal producers, one of the biggest threats to cereal seedlings is disease.
The first step in reducing seedling disease is to use clean seed that is free of any pathogens. Growers can do this by either purchasing certified seed or by testing their own at an accredited lab. Getting seed tested is an easy and inexpensive way to ensure it does not contain any pathogens.
Many growers send samples away for a germination and vigour test; however, it is important to do a full fungal screening as well. Planting infected seed can result in widespread distribution of disease within the crop and allows for an increased number of infection sites. Planting seed that is free of disease is also a way of limiting the introduction of new pathogens into a field. This is especially true when looking at the spread of seed-borne diseases such as Fusarium graminearum.
The use of seed treatments is a great insurance policy that will protect seed against early-season root rots and blight caused by cold and wet soil conditions. Treating seed with a fungicide can prevent any potential pathogen from entering the seed and damaging the seedling — and will provide two weeks or longer protection once the seeds are in the ground.
Most seed treatments on the market will also protect against later-season diseases including smuts and bunt. Many seed treatments include insecticides, which help inhibit insects from feeding on newly germinated seedlings. Any spots on the seedlings where insects chew is an opening for disease to form, and spending the extra money on treatments with a combination of fungicide and insecticide can be very beneficial. When treating seed, aim to achieve uniform coverage on all seeds and make sure to use the recommended rate of application to achieve the best results.
Crop rotation is another method to decrease the risk of seedling disease. By extending crop rotation, growers can reduce the amount of pest population in the soil. Some pathogens can survive in the soil or on crop residues from year to year in the form of sclerotia, spores or hyphae.
Continuous cropping can build up these pathogen levels to an unmanageable level. It is important to rotate out of host crops to reduce the inoculum in the soil. Saying this, some pathogens such as Rhizoctonia and Pythium species have such a wide host range they are very hard to control, even with proper rotation. Therefore, disease control needs a broad-spectrum approach and management plan.
Disease management can be a challenge, but taking the right steps early on, with clean seed, getting the extra layer of protection from seed treatments and considering crop rotation, growers can get ahead of and prevent diseases in their crops.