April 15, 2004
Keep your guard up against Anthracnose, advises Luis del Rio, North Dakota State University plant pathologist.
In 2002 and 2003, NDSU documented the presence of a half dozen infected fields and seed samples.
No one knows what 2004 will bring, del Rio says.
If the Anthracnose spreads it can be devastating. The disease is difficult to control and has the potential if unchecked to wipe out yield potential.
Anthracnose is a constant threat because it has been found in seed sources so far mostly from Canada and it can survive under the seed coat for five years if the seed is stored in a cool area, It can also overwinter on crop residues for up to two years.
The disease is spread mostly by planting infected seed. Symptoms are readily visible on the seed. But it only takes a few seeds per bag to introduce the disease in a field. Anthracnose moves about 15 feet with every .4-inch rainfall.
To guard against introducing the Anthracnose, del Rio recommends the following dos and donts.
" Do buying certified seed tested thoroughly for Anthracnose. (The North Dakota Seed testing lab uses a large sample to increase the odds of detecting infected seeds if they are present in a lot). Pintos are most susceptible. Envoy, Newport and Fleetwood navy beans and Montcalm kidney bean varieties are resistant.
" Do maintain a two to three year crop rotation.
" Dont plant adjacent to a known infected field.
" Dont enter fields when the plants are wet because you can spread the disease from plant to plant.
" Do use a fungicide if you identify the disease early. Labeled products include Headline, Quadris, Amistar, Topsin and Chlorothalonil.
Photo: Carl Bradley, NDSU Extension Plant Pathologist