Pulse Root Rot Network

Developed by the Root Rot Task Force with members from Alberta Pulse Growers, Manitoba Pulse and Soybean Growers, and Saskatchewan Pulse Growers

The need for a Pulse Root Rot Network (PRRN) was identified in 2021, when Canada’s pulse grower associations developed a National Pulse Research Strategy to identify research priorities and coordinate pulse research across Canada. In this strategy, controlling root rots in pea and lentil, in particular Aphanomyces and Fusarium spp., were identified as a top priority. The PRRN was launched in 2022 by the western Canadian pulse crop commissions (SPG, APG, MPSG) to catalyse a collaborative approach to root rot research and management focused on agronomy, breeding, and pathology in peas and lentils.

Mission: Eradicate the risk of root rots in pulses

Root rot complex causes significant yield impacts and limits production areas for peas and lentils. Aphanomyces eutiches, Fusarium sp., and other fungal pathogens, dominate the root rot complex. Profitable and sustainable pea and lentil production require us to eliminate this risk. The Root Rot Task Force has developed a strategic action plan to address the challenges pulse growers face due to root rot complex. Our mission is to eradicate the risk of root rots through a coordinated, collaborative effort across the pulse industry. 

Root rot pathogens can have a devastating impact to plant performance and are a significant threat to pea and lentil production with substantially reducing yields of up to 70% in peas in high root rot conditions. Root rot pathogens are seed or soil-borne diseases and can infect the plant at any stage between germination and maturity, and at any part of the root system up to a short distance above the soil.

Root rot causes a brown discolouration of the roots and the plant is unable to develop a strong root system. With this disease, the plant wilts, there is reduced plant growth, yellowing of leaves, root decay and premature death. As the damage is initially done at the roots, root rot may not be immediately obvious. Root rot may also reduce the pea or lentil protein content as the pathogen attacks the nodules. This impacts the plant’s ability to fix nitrogen and prevents normal nutrient and water uptake.

The root rot pathogens include Aphanomyces euteiches, Fusarium spp., Pythium spp., and Rhizoctonia solani. These can also be considered as a root rot complex where more than one pathogen is present. Aphanomyces euteiches and Pythium spp. are organisms that belong to a group of fungal-like root pathogens and are considered water molds. They do particularly well in saturated soils.

Aphanomyces was first reported in Manitoba in 1997 and into the early 2000’s. It was only positively identified in Saskatchewan in 2012, and in Alberta in 2013. It is likely, however, that root rot pathogens have been present for much longer as it is native to our soils.

Aphanomyces has had the greatest negative impact on yields due to difficulty in managing the disease. The length of time that the oospores (resting spores) can survive in the soil, the absence of genetic resistance, and the lack of effective control measures makes it the most damaging root rot pathogen. Fusarium spp. and the other pathogens can also work with Aphanomyces to increase the severity of the disease. Fusarium is the most common root rot disease in pulses and can also infect cereals and other rotational crops, however, its impacts are less severe as there are pea and lentil varieties with partial resistance and some available control measures. Pythium spp., and Rhizoctonia are also less worrisome as both can be controlled by certain seed treatments.

Research efforts since 2012 have increased our understanding of root rot pathogens, their life cycle, virulence, diagnosis, and the interaction between the plant, the pathogen, and the environment. More work is needed to understand what factors could potentially impact the survival of the resting oospores, novel management strategies and control options, and breeding of resistant or partially resistant varieties.

Decision Making Tree for Producers & Agronomists

The best route for controlling root rot at this time is prevention and knowing the root rot risks. Know your field’s history; test your soil; manage the crop rotation including limiting the frequency of susceptible crops; utilize best soil management practices (good nutrition, and reduce compaction). Maintain good field records. How well did the crop do last time? What were moisture levels then and in subsequent years? Were there patches of diseased and dead plants in the field? Did these patches coincide with water pooling areas and waterways?