Posts Tagged ‘septoria leafspot’

Soybean Disease Update – June 24, 2011

Friday, June 24th, 2011

Soybean Rust Report
There is very little soybean rust activity to report. It has been very dry and hot in the Gulf Coast region where soybean rust overwinters. It has only been found on kudzu so far this season. The risk of soybean rust is very low now even for the southeast. I continue to monitor soybean rust development in the south and will provide a report periodically as the season progresses.

Septoria Brown Spot
Septoria brown spot is one of the earliest fungal diseases that we see on soybean and can be found on the unifoliate leaves and the lower trifoliate leaves when it is present. Badly infected unifoliate leaves will usually fall from the plant and we will not see this disease again until the soybeans canopy and conditions would be favorable for infection. Most seasons this disease is not yield limiting.

Septoria brown spot on unifoliate leaves of soybean.

 

Soybean Disease Update – July 2, 2010

Friday, July 2nd, 2010

Bob Mulrooney, Extension Plant Pathologist; bobmul@udel.edu

Soybean Cyst Nematode
SCN was diagnosed this week on soybeans. If you see stunting and yellowing, carefully dig up the affected plants with a shovel or trowel and gently shake the soil from the roots. White or yellow females will be seen attached to the infected roots if present. They are small, much smaller than the nitrogen fixing nodules, but can be seen with the naked eye. A 10x hand lens makes the task much easier to see the lemon shaped females. If it is not clear what the problem is or cysts cannot be seen a soil sample of the affected area can be taken and checked for SCN or other nematodes. Test bags and more information are available at the county Extension offices and forms and info at the Plant Diagnostic Lab site at http://ag.udel.edu/extension/pdc/pdf/Nematode_Assay_taking_samples.pdf . We will be having a Soybean Cyst Nematode Workshop on August 3. See the meeting announcements for more information and registration forms.

 

Septoria Brown Spot
Septoria brown spot has not been as prevalent as last year but it has been seen in a few fields so far. It is one of the earliest fungal diseases that we see and can be found on the unifoliate leaves and the lower trifoliate leaves when it is present. Badly infected unifoliate leaves will usually fall from the plant and we will not see this disease again until the soybeans canopy and conditions would be favorable for infection. Most seasons this disease is not yield limiting.

 

Septoria brown spot on unifoliate leaves of soybean

Soybean Disease Update — June 26, 2009

Friday, June 26th, 2009

Bob Mulrooney, Extension Plant Pathologist; bobmul@udel.edu

Septoria brown spot has been favored by all this wet weather and is easily found on the unifoliate leaves and the lower trifoliate leaves in most areas. These will usually fall from the plant and if it dries out we will not see this disease again until the soybeans canopy and conditions again would be favorable for infection. Most seasons this disease is not yield limiting. Spots seen this week were small but very numerous in one variety trial that I checked. septoriabrownspotSeptoria brown spot on unifoliate leaves of soybean

Soybean Rust Update
Soybean rust was reported in Geneva, Covington and Conecuh counties in south-central Alabama on kudzu on June 24. The disease was found at very low levels at each site which included two seperate kudzu patches in Covington County. On June 22, soybean rust was reported in a soybean sentinel plot in Acadia Parish in Louisiana. Soybean rust scouting continues in the U.S. and Mexico. The current conditions in the South are not going to be very favorable for rust development due to high temperatures.

 sbrmap26jun09

Soybean Diseases

Thursday, June 26th, 2008

Bob Mulrooney, Extension Plant Pathologist; bobmul@udel.edu

Soybean Rust Update
Soybean rust was confirmed in Taylor County, Florida, on kudzu on June 20th. This is the first find in that county in 2008. Since the beginning of 2008, soybean rust has been reported on kudzu in one county in Alabama; eleven counties in Florida (two of these counties had reports on coral bean and snap bean, and one county had a report on soybean); three counties in Louisiana; one county in Mississippi, and three counties in Texas. Reported infected kudzu sites in many counties have been destroyed. Rust was also reported in three states (5 municipalities) in Mexico on yam bean and soybean. These too have been destroyed or are no longer active, except for the find in Chiapas.

Septoria Leafspot
Septoria leafspot is the first foliar disease that is usually seen on soybean. In areas that had adequate moisture or irrigation and cool temperatures it can be found on the first true leaves (unifoliate). It can cause some early leaf spotting and dropping of those first leaves but the plants rapidly grow out of it until later in the season. If wet weather occurs later in August and September it is often seen again. In our area it is the one common disease that can look like soybean rust when the spots are small.

 

Septoria brown spot on soybeans