Wheat Foliar Disease Update: April 11, 2014
Wheat diseases have been essentially non-existent this winter. No rust to report and very little of much any other foliar diseases is great news for our wheat farmers.
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Posts From Tom Allen, Extension Plant Pathologist
Management Practices to Reduce the Development of Fungicide Resistance in Soybean: Part III, Strobilurin-Resistant Frogeye Leaf Spot in Mississippi
Strobilurin-resistant frogeye leaf spot continues to be a topic of conversation. During 2012 two MS counties were confirmed to have strobilurin resistant frogeye leaf spot. Since that time a large survey has been conducted in MS to determine how widespread the resistance is within the fungal population in MS.
Management Practices to Reduce the Development of Fungicide Resistance in Soybean: Part II, Choosing Fungicide Products and Rates
Fungicides have become an important management alternative for diseases such as frogeye leaf spot. However, with the addition of the strobilurin-resistant fungus responsible for frogeye leaf spot, caution must be taken when applying fungicides to not increase the likelihood of fungicide resistance from developing. The specific characteristics of the main fungicide classes labeled for application in soybean systems are outlined. In addition, a table that includes the specific components of the pre-mix products when the labeled rates are applied is included.
Management Practices to Reduce the Development of Fungicide Resistance in Soybean: Part I, Improving Disease Management Practices
Fungicide resistance has continued to be a hot topic during the off-season. Since 2010, fungicide resistance within the frogeye leaf spot fungal population has been documented in several states including Mississippi. To prevent the development of fungicide resistance from increasing several important steps can be followed. Several of these specific topics will be outlined in this three part series regarding fungicide resistance.
Vegetative Stage Corn Fungicide Applications in the Mississippi Production System: 2013 Large Plot Trials
During 2013, several fungicide trials were conducted to determine the benefit of vegetative growth stage timings in corn. Two large plot trials were conducted in east MS with the help of Dr. Dennis Reginelli. In this blog post, the results of two large plot trials were presented from one nonirrigated and one irrigated field setting. Small plot trial data will be reported at a different date.
Thinking About Planting Medium-grain Rice?
In Mississippi, research indicates that management of medium-grain varieties is similar to that of long-grain varieties.
Late Winter Pyrethroid Applications in Wheat for Aphid Control
Over the last several years we have seen a consistent response in wheat yield when a pyrethroid was used during the late winter months (late January-February). Often when this application goes out it is very difficult to find aphids at
Future of Agriculture Graduate Student Competition Results
The results from the Second Annual Future of Ag Graduate Student Competition are included in this post.
2013 Soybean Variety Trial Disease Ratings: Maturity Group V Frogeye Leaf Spot and Cercospora Blight
Included in this blog post are ratings collected for frogeye leaf spot as well as Cercospora blight from the 2013 Maturity Group V soybean variety trials. Trials were conducted in Brooksville, Clarksdale (irrigated), Falkner, Longwood, Olive Branch, Raymond, Stoneville (clay and loam). The conventional/LibertyLink trial was only conducted at the Brooksville, Falkner, Longwood, and Stoneville (clay) locations. Ratings were collected based on a 0-9 and are presented from each location for each variety so a range of ratings is available across all environments encountered during the 2013 season.
2013 Soybean Variety Trial Disease Ratings: Maturity Group IV Frogeye Leaf Spot and Cercospora Blight
Included in this blog post are ratings collected for frogeye leaf spot as well as Cercospora blight from the 2013 Maturity Group IV soybean variety trials. Trials were conducted in Brooksville, Clarksdale (irrigated), Falkner, Longwood, Olive Branch, Raymond, Stoneville (clay and loam). The conventional/LibertyLink trial was only conducted at the Brooksville, Falkner, Longwood, and Stoneville (clay) locations. Ratings were collected based on a 0-9 and are presented from each location for each variety so a range of ratings is available across all environments encountered during the 2013 season.
Delta Ag Expo, Cleveland, MS – January 23 & 24, 2014
Attached please find the agenda for the Delta Ag Expo in Cleveland, MS. Make careful note that the dates of the meeting have changed from previous years due to a minor scheduling conflict with the Bolivar County Exposition Center.
East Mississippi Soybean Variety Trial Report
Attached in this blog post are the variety trial results from the North Mississippi Research and Extension Center in Verona, MS. Harvested yield as well as variety response to natural infection from Cercospora blight and frogeye leaf spot are included in the associated tables.
Soybean Viruses Cause Important Diseases too
Virus-infected soybean material has been observed almost statewide this season. The high numbers of bean leaf beetles can be blamed for some of the observed viruses; however, bean leaf beetles are not the only insects that can vector soybean viruses between plants. This specific blog update presents information on the three most commonly encountered soybean viruses in the MS soybean production system.
Soybean Disease Update: September 21, 2013
Soybean disease questions still consider to be raised throughout MS. Even though soybean rust has been detected in 45 counties to date it appears we will have another season where yield losses as a result of soybean rust will be extremely limited and may only have occurred in a handful of fields. When making plans for next year consider sampling for nematodes in light textured soil classes. In addition, planting a frogeye susceptible variety in several years in a continuous soybean system may increase the likelihood of frogeye causing substantial yield loss.
Managing Late Season Stink Bugs in Mississippi Soybean
Over the last month we have had numerous questions about terminating stink bug applications in late season soybeans. Typically we manage stink bugs until near harvest but there are several things to consider before making an application to control stink bugs in beans beyond R6 growth stage.
Storing Harvested Corn and what to Expect from High-Moisture Corn
Numerous questions have come in over the past few weeks regarding proper grain storage. Maintaining moisture below 15% is extremely important to reduce the likelihood of fungal growth. However, not all fungi that develop on harvested grain are problematic and toxin production is not something that can occur overnight. Even though fungi such as Aspergillus flavus can produce a green fungal growth on harvested grain not all fungi that grow on grain can be considered to be A. flavus.
Sudden Death Syndrome Look Alike Part I: Red Crown Rot
Red crown rot has been identified in additional fields in east MS throughout the 2013 season. Prior to 2013 only two counties had been identified as having red crown rot. However, three additional counties have been added this season (Clay, Newton, Union). Red crown rot symptoms can be misdiagnosed as several other diseases, including sudden death syndrome (SDS).
Foliar Soybean Disease Update: August 31, 2013
Foliar diseases of soybean continue to be observed throughout the MS soybean production system. Over the past week additional counties containing soybean rust have been observed throughout the state. Stay tuned to information on the Crop Situation Blog regarding additional counties with soybean rust infected plant material should management suggestions change.
Frogeye Leaf Spot Fungicide Preliminary Data (Updated 8/30/2013)
Numerous questions over the past few weeks regarding how well certain fungicide chemistries are managing frogeye leaf spot. Attached please find preliminary rating data from Starkville and Stoneville on how well particular products are managing observable symptoms of frogeye leaf spot. Additional data to follow as we continue to rate plots.
Soybean Disease Update: August 18, 2013
Numerous diseases continue to be reported from throughout the MS soybean production area. Frogeye leaf spot continues to be the main foliar disease observed. Additional soybean rust was reported from Adams County this past week. However, since low levels of the disease continue to be reported the suggestion remains that farmers wait and watch the available information and allow soybean to get as close to reproductive developmental stages before making a fungicide application.
Not Everything is as it Seems: Fungicide Phytotoxicity and Plant Diseases
Phytotoxicity following a foliar fungicide application is not a commonplace occurrence in our soybean production system. In certain situations, the symptoms that express themselves when a fungicide application is made in the heat of the day can manifest themselves similar to characteristic foliar disease symptoms. Sudden death syndrome (SDS) is a common occurrence from the standpoint that we observe the disease annually but rarely does it impact yield and in fact we normally suggest that SDS simply means you’ve raised some great soybeans in that particular field. Keep in mind that SDS will only occur on light soil texture classes and normally not across an entire field as a situation such as phytotoxicity could.
Rice Leaf Blast Detected in a Blast-Susceptible Variety in Bolivar and Sunflower Counties
Blast of rice was positively confirmed in three rice fields on Tuesday afternoon. Blast lesions are specific in that the generally form a diamond-shaped lesion on the leaf.
Foliar Leaf Spots Observed in Cotton
Cotton leaf spots have been observed in several fields again this year shortly after flowering. Positively confirming the particular disease is the most important event to determine a potential management scenario. The difference between the members of the “potash complex” as well as target spot are distinct, but numerous lesions need to be observed to positively identify the causal organism.
Soybean Frogeye Leaf Spot: Management Decisions for the Disease Following an R3/R4 Strobilurin Application
Frogeye leaf spot continues to be one of the main foliar diseases observed in the 2013 soybean crop. In several situations a fungicide has applied and frogeye continues to be an issue. In the current blog post several pieces of information are included to help aid decisions in whether or not a particular variety may be susceptible or resistant to frogeye. In addition, a table of the labeled fungicide products for use to prevent yield loss as a result of frogeye leaf spot are included.
Corn Disease Update and Late Fungicide Suggestions: July 19, 2013
Corn fungicide questions continue to be made even in situations where corn has reached dent. In general, making a fungicide application at dent or later corn growth stages only pays off if excessive disease pressure is observed prior to the fungicide application being made. Moreover, making a fungicide application to a foliar disease tolerant hybrid will likely not pay off since the genes present in the hybrid should be relied on for preventing yield loss as a result of foliar disease.
