Aphanomyces
Aphanomyces
While not listed as a disease under the Alberta Pest Act, Aphanomyces is a common cause of root rot in pulse crops. The soil-borne pathogen Aphanomyces euteiches causes damage to the roots of a number of legume plants, resulting in the plant becoming wilted and ultimately dying prematurely. Unfortunately, once Aphanomyces has infected the soil, it cannot be eradicated. Knowing the risks and prevention are the best options to help reduce the risk of Aphanomyces on your land.
There can be an increase in the risk to root rot if there is the following conditions:
- Wet conditions
- Cool temperatures early in the season
- Shortened rotations
- Heavy textured soils
- Soil compaction
- Nutrient Deficiency
- Herbicide residues
- Low seed vigor
Diseased plants can have honey-brown discoloration of the roots, yellowing and wilting of the lower leaves, and poor root growth. Aphanomyces symptoms can appear within one to two weeks of initial root infection.
Loss of yields can be influenced by infection timing- early infection resulting in premature plant death can cause direct yield loss. Infection later in the growing season can cause issues while harvesting, including weakened stems resulting in lodging and delays in crop maturity.
Best management practices for preventing the spread of Aphanomyces include:
- 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.
- Avoid compacted soil.
- 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.