The disease situation in MS soybean fields has certainly increased over the past 7-14 days. Active aerial web blight, Cercospora blight, soybean rust, and target spot remain the most commonly observed diseases over much of the production area.
Unsightly spots on cotton leaves are becoming more common as the year progresses. There are a number of things that can cause cotton leaf spotting including herbicide injury, disease, insect feeding (i.e. spider mites), or numerous other factors. The focus of this
Yesterday, light soybean rust infection was observed in Noxubee County, MS in soybean plants beyond the R5.5 growth stage. The specific information in this blog post should serve as an update to the soybean rust disease situation as well as including some general guidelines with regards to potential disease management scenarios.
Numerous soybean varieties were observed to be severely affected by target spot during 2016. Symptom expression on the specific varieties may be difficult to tell apart from other diseases. Some of the varieties were not commercially available for the 2017 season. However, in some rare situations some of these varieties may be planted and will likely respond this season in a similar fashion to what was observed during 2016 as a result of the continued wet weather during the 2017 growing season.
Several foliar diseases have increased in incidence throughout MS over the past several weeks. Root diseases, such as sudden death syndrome, taproot decline and one field of stem canker continue to be observed in the production system. The current foliar disease situation is outlined in this particular post.
You are welcome to attend the Row Crop Update at the Mississippi Agricultural Industry Council Conference. The conference is hosted at Perdido Beach Resort in Orange Beach, Alabama on Wednesday, July 26.
Bacterial blight of cotton has shown up in younger cotton in east and west MS. At present, 10 counties have been observed to contain bacterial blight cotton. To date (July 6), target spot has not been observed in the MS cotton crop.
The soybean disease situation continues to change throughout MS depending on growth stage situations in each field. Over the past week root diseases have been commonly observed. The first soybean rust of the season was observed in southwestern MS on kudzu.
Increased reports of disease in the corn crop in MS have been made over the past week. Normally, as corn matures, the incidence and severity of corn diseases observed with increase. Presently, common rust, Diplodia leaf streak, northern corn leaf blight, and southern rust can all be observed in our corn production system; however, southern rust has only been observed on an extremely limited number of acres to this point in the season.
Over the past several years, fungicide pre-mix products have dominated the marketplace. Keeping up with the specific chemical classes within each product can present a challenge. Included in this blog post are some information to aid in making fungicide decisions.
Diagnosing common and southern rust in the field can oftentimes be difficult. Subtle differences between the two diseases can occur at different parts of the growing season as well as sections of the crop canopy.
Limited soybean diseases have occurred throughout the MS soybean production system. Observations of Septoria brown spot and taproot decline have been quite common this season. Lesions that result from herbicide injury have also been commonly observed, but should not be cause for concern.
Over the past week calls have started to be received regarding the automatic fungicide application in soybean. On-farm, large plot trials were conducted during 2015 and 2016 to assess the benefit of several different fungicide products and to reevaluate the automatic application timing. At present, we believe that a mixed mode of action fungicide, or one that provides more than one mode of action would be more beneficial than the stand-alone strobilurin (QoI) fungicide application that has become popular over the past decade.
The Mississippi corn crop is generally on pace to tassel earlier than normal this year. Thus, how may this affect how the corn will respond to mid-season application of various management inputs, including nitrogen fertilizer and other products? This article will discuss factors and distinct scenarios that could dramatically effect realistic corn response.
Approximately 20% of the cotton acres intended in Mississippi have been planted; however, given the cool, wet weather as well as high winds in the north Delta over the past several days, a number of re-plants will likely be taking place.
Limited wheat acres in MS have meant for a fairly quiet winter. However, the observation of wheat diseases has increased over the past several weeks with the major questions coming from either vernalization issues (lack of chilling hours) or leaf rust.
Target spot management in soybean production systems remains a hot topic going into the 2017 season. The environment that occurred during late July and early August 2016 made us respect a disease that is often “out of sight and out of mind”. Fungicide data from two efficacy trials conducted during 2016 are included in this blog post.
Target spot was one of the main diseases that occurred during 2016. Normally a disease of little consequence in soybean as well as cotton, severe target spot outbreaks were observed in both crops. Making decisions regarding the occurrence of target spot during 2016 are difficult since the environment during key plant growth stages was the most important ingredient for the occurrence of target spot last season.
The MSU OVT soybean locations were rated for disease during the 2016 season. Multiple diseases were rated at multiple locations. In the past, Cercospora leaf blight and frogeye leaf spot have been the two main diseases rated. In 2016, Septoria brown spot as well as target spot were included in the ratings.
A Maturity Group IV and V variety trial was conducted in Verona, MS at the NMREC during the 2016 season. Yield and disease data are included in the attached report for all entries contained in the trial (RoundUp, Conventional and LibertyLink).
The On-Farm Soybean Variety Demonstration Program is conducted using a set of varieties with proven performance. These varieties are grown in a production setting on various soil types and management systems around the state. Demonstration sets for both maturity group
The cultivars contained in the Mississippi State University Official Variety Trial (OVT), as well as a few added cultivars, were field-evaluated for their susceptibility/resistance to stem canker. Trials were conducted in Stoneville with toothpick-inoculated plants during the 2016 season. Tables contain the average ratings (on a 0-9 scale) as well as an assessment of resistance to stem canker (R, MR, MS, S) based on the ratings conducted.
Foliar diseases continue to be observed throughout the MS soybean production system. Cercospora blight, frogeye leaf spot and target spot have been commonly observed. Soybean rust continues to be observed at low levels in areas where the disease has occurred following the rainfall received over the last month.
Following the rainfall received over the past 10-14 days soybean diseases have greatly increased. Septoria brown spot, target spot and soybean rust (in isolated geographic locations) have all increased throughout MS.
As we approach soybean physiological maturity, determining the specific soybean growth stage can aid in several important management decisions. Distinct differences exist between the R6 and R6.5 growth stage.
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