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Aphanomyces is one of the many varieties of root rot pathogens that can affect crops. Crops such as peas, lentils, beans, alfalfa, vetch, and clover can be infected by Aphanomyces [1]. This particular pathogen can survive in the soil for 10 plus years without needing a host, and will lie in wait for the right conditions to present themselves to strike [2]. Aphanomyces is a known issue for areas throughout the US, such as the Midwest, where it has plagued Wisconsin since 1925 [3]. In Canada, the Saskatchewan Ministry of Agriculture asserts that Alberta and Manitoba have been experiencing cases of Aphanomyces for some time, but this pathogen was only first identified in Saskatchewan in 2011. It has also been found in Europe, Australia, New Zealand, and Japan. If Aphanomyces is a known concern for your area, here is what you need to know:

WHAT ARE THE IDEAL CONDITIONS FOR APHANOMYCES TO STRIKE?

• A temperature range of 22-28° degrees Celsius
• Water logged soil or excessive moisture conditions
• Compacted or water holding soils such as clay are more susceptible

WHAT ARE THE SIGNS OF AN APHANOMYCES INFECTION IN YOUR CROPS?

• Yellowing or wilting of plant leaves
• Poor or stunted growth of crops
• Roots will be a shade of gray, honey brown, or blackish brown due to rotting
• Reduced volume and function of root network
• Common in areas of the field with poor drainage; i.e. compacted or high clay content zones
• For Peas and Beans the presence of lesions  on the stem or leaves is common

HOW TO MANAGE FOR APHANOMYCES ON YOUR FIELDS?

• There are currently no seed treatments for Aphanomyces, however there are seed varieties that are bred to be resistant to this pathogen [1]. The availability and variety of these cultivars is dependent upon your region.
• Choose Crop Rotations tolerant to Aphanomyces to help manage your pathogen levels; these include Chickpea, canola, flax, soybean, cereal crops and some cultivars of faba bean [1].
• Manage the water on your fields  by improving your soil drainage [3].

If you suspect your crops may be infected with a form of root rot such as Aphanomyces seek advice from your local agricultural government agency.  They will direct you through the next steps of confirming an Aphanomyces infection through soil and/or plant tissue testing as well as advise you on how to best manage the pathogen levels on your fields.culture,

Written and Published by Jessica Kohls, BSc, PgCE – Dutch Biologist