Disease Outlook for 2008
June 18, 2008
By Dr. Rubella Goswami, NDSU Dry Bean and Pulse Pathologist and Dr. Sam Markell, NDSU Extension Plant Pathologist
As everyone knows, its hard to predict disease. Even if we were exceptional at it, our predictive skills are subject to weather, which we cant forecast more than a couple days in advance (some might say hours!). However, here is a look at the usual and unusual suspects.
When soils are cool and wet, we tend to have greater root rot problems. Throughout the region, soil temperatures have been below normal. Low soil temps can slow down germination and increase the exposure of the young, sensitive plants to pathogens. In our region, we have both dry and wet areas. Where there is lots of water, we would expect a favorable environment for root rot pathogens.
Its too early to make any white mold predictions, but I doubt that its appearance would surprise anyone. Just remember, the conditions that favor white mold also tend to favor yield!
Last year we had lots of bacterial infections. This was largely a result of excessive rain, wind, and hail (some would argue typical ND weather) providing a favorable environment for disease. Bacteria pathogens can survive on seed, so if you had bacterial disease last year, and opted to keep and replant that seed this year, you might be looking at bacterial diseases again.
Dry Bean Rust
Rust hasnt been common in the last few years. We see it here and there, but not causing the epidemics of the past. This is due in a large part to effective resistance genes in varieties. But dont count rust out. New rust races can appear with no warning, which could make rust a major player again.
Anthracnose hasnt materialized as a major player in North Dakota. However, it does have that potential, and if you find anthracnose in your field, youll want to pay attention to it.
Last but not least, soybean rust can infect beans. Soybean rust only survives the winter in the Deep South, and then blows north as the summer progresses. Since we are in North Dakota, the disease has a long, long way to spread before paying us a visit. It is not impossible that soybean rust could make it to the North Dakota, but it hasnt even got close in the last few years. Should it actually get here, it would have to get here in time to cause yield loss for us to be concerned. The spread of soybean rust is monitored at www.sbrusa.net.
Diseases are very dynamic, and what is causing the most yield loss today may not be what causes the greatest yield loss tomorrow. Both of us are going to be out in fields frequently this summer to keep an eye on the beans. We will be surveying for the prevalence of different diseases, and taking samples of the pathogens that are causing them. We can use the information and the pathogens collected to try and improve (and develop if necessary) management strategies to deal the disease pressures, and conduct research that will net real solutions for real problems. This information also keeps us on the front lines if new diseases blow-up on us. We are looking forward to meeting people at field days and plot tours this summer.
Good luck with the beans!