Stem Canker On Soybean

Jul 13, 2023

soybeans are grown, but may not be recognized as much as it occurs. Stem canker can kill whole plants or parts of plants. It can be confused with Phytophtora rot. Two different kinds of stem canker are known, northern and southern, which seem to be geographically limited to some degree but their ranges may overlap. Soybean cultivars can have resistance to stem canker. This disease often appears to kill or damage scattered plants, but in some cases large areas can be killed and yield losses can be significant.

Symptoms

Early symptoms are reddish-brown lesions that appear at the base of branches or leaf petioles. These small lesions can develop into elongated, sunken, dark brown cankers that spread up and down the stem. Tiny black dots called perithecia (spore producing fungal structures) may appear on the stem singly or in clustered groups on plants killed by stem canker. Plant parts above the lesions may die. Reddish-brown discoloration may also occur inside the stem, and pods can abort. Leaves may develop necrosis and chlorosis between the veins and may remain attached after death. Lesions often develop at and remain darker at nodes, but may extend to the soil line and create a situation easily confused with Phytophthora rot.

Conditions and timing that favor disease

Prolonged wet weather, especially early in the season favors stem canker. Symptoms are often seen from mid-July to harvest, especially in susceptible varieties. Reduced tillage may also favor this disease.

Causal pathogen

Northern stem canker is caused by the fungus Diaporthe phaseolorumvar. caulivora. Southern stem canker is caused by the related fungus Diaporthe phaseolorum var. merdionalis. These pathogens overwinter in infested soybean residue, and may be spread with infected seed.

Disease management

Stem canker can be reduced by planting resistant varieties with resistance to this disease. Delayed planting and foliar fungicides may be beneficial. Tillage may reduce disease problems in fields where this disease has been a problem. Crop rotation with non-host crops such as wheat and corn may help to reduce stem canker.

Source : umn.edu

Video: Why Invest in Canada’s Seed Future? | On The Brink: Episode 3

Darcy Unger just invested millions to build a brand-new seed plant on his farm in Stonewall, Manitoba so when it’s time for his sons to take over, they have the tools they need to succeed.

Right now, 95% of the genetics they’ll be growing come from Canadian plant breeders.

That number matters.

When fusarium hit Western Canada in the late 90s, it was Canadian breeders who responded, because they understood Canadian conditions. That ability to react quickly to what’s happening on Canadian farms is exactly what’s at risk when breeding programs lose funding.

For farmers like Darcy, who have made generational investments based on the assumption that better genetics will keep coming, the stakes are direct and personal.

We’re on the brink of decisions that will shape our agricultural future for not only our generation, but also the ones to come.

What direction will we choose?

On The Brink is a year-long video series traveling across Canada to meet the researchers, breeders, farmers, seed companies, and policymakers shaping the future of Canadian plant breeding. Each week, a new story. Each story, a piece of the bigger picture.

Episode 3 is above. Follow Seed World Canada to catch every episode, and tell us: Do you think the next generation will have the tools they need to success when they takeover? How is the future going to look?