Scouting for Disease in Your Pulse Crops JUN 26 2013 | Producers | Blog Post
Rotting stems, decaying roots, stunting – by the time these symptoms appear in your fields, it may already be too late to salvage your pulse crop. Scouting for disease is one of the most critical things you can do during the summer months to avoid substantial yield loss, harvest problems, and reduction in seed quality.
The severity and prevalence of disease in pulse crops depend largely on weather, crop rotations, and presence of disease in the field. Many of these factors are outside of your control – but there are a number of ways to reduce the severity of the infection and, hopefully, reduce its impact on your crop.
Use proper rotations. A four-year crop rotation that includes non-susceptible crops and a minimum of four years between pulse crops can help break the disease cycle. Because some diseases are wind-borne, avoiding planting adjacent to the previous year’s pulse crop is also advisable. If disease is not a problem, shorter rotations can be used but are not recommended.
Use certified seed. Planting disease-resistant varieties and certified, disease-free seed can help prevent disease in your fields.
Treat your seed. To protect your crop from fungal diseases that may be both present in the seed, as well as those that may attack the plants early in the growth stage, seed should be treated prior to planting. Check Alberta Agriculture’s Crop Protection Guide (the Blue Book) for available seed treatments and rates to use.
Use care when handling seed. Mechanically damaged seed is prone to fungal diseases during germination. Young seedlings are also less vigorous and therefore more susceptible to these diseases.
Use chemical disease control when necessary. Few registered fungicides are available for pulse crops. The most up-to-date information on the use and recommended rates is available in Alberta Agriculture’s (the Blue Book) Crop Protection, Agdex 606-1.
Use sound agronomy and aggressive disease scouting techniques. In addition to using appropriate crop rotations, planting certified seed, treating the seed, adhering to recommended practices for seeding rates, row spacings, time of seeding, and depth of seeding can reduce the severity and spread of disease. Rolling fields when the plants are wet can also spread disease, as can scouting when fields are wet. Many symptoms of disease are easily identified through persistent field scouting, and early diagnosis is essential if you hope to apply appropriate control measures in time.
Disease scouting must be conducted throughout the growing season. To scout for disease…
- Review the field history, identifying any fields that have had problems with disease in the past.
- Scout every week, checking any fields that are prone to disease first.
- Select five to 10 random sites throughout the fields, keeping in mind that row ends often have the highest risk of disease. Look closely at the leaves and stems of the plants for any sign of disease. Mark these areas with a flag and return to these areas as an accurate way to monitor disease progress between scoutings.
- Identify any diseases and take the appropriate measures to control them immediately, as some diseases can progress quickly. If you are uncertain about diagnosis, take one or two plants to an agronomist for help in identification.
- Map the diseased areas and monitor them frequently for signs of disease spread.
Having a solid working knowledge of the most common types of disease can help you identify and treat infection in your field.