Aphanomyces root rot can be a true scourge for pea and lentil growers. It can strike pulse crops at any time of the season, and it sticks around in the soil for years, making it a multi-season problem. No matter how you slice it, Aphanomyces is a devastating problem to deal with.
Root rot is a disease that attacks below the surface, causing extensive damage to the roots leading to wilted crops or premature death. It’s often hard to diagnose early since most of the damage occurs underground. But above-ground symptoms usually show up 10-14 days after a heavy rainfall event in the form of yellowing on the lower leaves in areas where there is high infection. By the time it becomes noticeable above ground, the plant’s yield potential has been greatly reduced having disastrous effects on your bottom line.
Understand the Signs to Reduce Risk
Once Aphanomyces populations are detected in your field, there is nothing that can be done to eliminate them. But with understanding, prevention and management, you can mitigate the dangers to your crop.
Knowing the stress factors that can contribute to an increased risk of root rot is the first step towards a healthy crop. While Aphanomyces can attack host crops anytime during the growing season, seedlings are especially vulnerable since they can easily be overtaken by disease when they are young. Wet and cool conditions early in the season can delay germination and emergence and weaken seedling health. Saturated soil at any time in the season also increases risk.
Soil compaction, nutrient deficiencies, and low seed vigor can render crops more susceptible to root rot attack.
Management For Mitigation
If you’ve had a root rot problem in your field, it’s important to note that susceptible crops, such as peas and lentils, should be avoided for 6–8 years, as the pathogen can persist in the soil for at least that long. Instead, consider a nitrogen-fixing crop that is resistant to Aphanomyces, such as soybeans, fava beans or chickpeas (moderately resistant).
If your field has not had noticeable Aphanomyces root rot issues, there are a number of best practices you can implement for growing healthy plants and mitigating disease pressures.
- Use a four-year crop rotation and avoid fields where pea/lentils were grown on above normal rainfall years in the past.
- Test soils proactively for Aphanomyces prior to seeding peas and lentils.
- Test seed quality.
- Use a quality seed treatment, especially if planting into cool soil.
- Plant in lighter textured soils that offer good drainage.
- Avoid compacted soil.
- Apply adequate nutrients.
- Maintain effective weed control of potential Aphanomyces host plants such as volunteer alfalfa, white clover, shepherd's purse and chickweed.
- At the earliest signs of a root rot infection test plant roots to confirm the type of root rot present.
- Avoid movement of soil between fields.
Apply a Seed Treatment
When it comes to seed treatments, a product that works as an early-season suppressant of Aphanomyces is your best bet, especially if early-season conditions are cool and wet. Allowing your crop to establish a strong, healthy root system as early as possible is key to fighting off the risk of Aphanomyces root rot. RANCONA TRIO by UPL can help pulse crops endure disease pressures, therefore minimizing yield loss.
In the case where fields have tested positive for Aphanomyces, RANCONA TRIO can help prevent the spread of the disease if the infestation is low to moderate. It can also keep spore levels down in fields where Aphanomyces is not yet suspected or detected as Aphanomyces is thought to be native to the Canadian prairies. With advanced technology and the combination of three powerful fungicides, RANCONA TRIO provides superior coverage and consistent protection under a wide range of conditions.
Peas and lentils are the most susceptible pulse crops to Aphanomyces, and there are currently no resistant varieties and plants are susceptible during their entire growth cycle. In severe cases, fields with high Aphanomyces levels in the soil have seen yield losses as high as 70%. None of this is information that any grower wants to hear. But the good news is that with a little vigilance, implementation of good agronomic practices and a seed treatment, you can drastically reduce your risk factors.
Find out more about RANCONA TRIO from your local UPL representative. You can be confident with UPL by your side, providing the best tools to meet your production goals.
