Oftentimes dealing with foliar wheat diseases can be a confusing topic. More often than not, physiological leaf spotting, or genetic leaf spot, can be observed in most wheat fields after flowering stages. However, the leaf spot symptoms are occasionally misdiagnosed as early leaf rust symptoms. But, rarely have I observed a disease epidemic in a situation where the specific “flecking” symptoms are regularly observed.
Scattered reports of wheat diseases have been made over the past two weeks. Limited leaf rust, stripe rust, and Septoria leaf blotch can be observed in some wheat fields. In addition, in some situations bacterial leaf streak can be readily observed on flag leaves in some limited situations. In some cases, bacterial leaf streak and Septoria leaf blotch can appear similar to one another. In most cases, Septoria leaf blotch can be observed in the lower canopy and likely will not move up the plant to the flag leaf. However, bacterial leaf streak can be more readily observed on flag leaves in some fields.
During 2012 fungicide application trials were conducted at a field site west of Greenwood, MS. Following a major wind event that occurred early in June, excessive greensnap was observed in plots that had received V6 foliar fungicide applications. Plots were assessed to determine if fungicides could consistently alleviate the occurrence of greensnap compared to untreated plots.
Oftentimes, deciding whether or not to make a fungicide application to corn in vegetative growth stages is not based on disease. Rarely are foliar diseases an issue in vegetative growth stages (save for extremely rare situations). More often than not, the decision to apply a fungicide at a vegetative timing is based on the theory of “plant health”, or physiological enhancements to the plant as a result of the fungicide that have been difficult to replicate in all situations.
Use the information contained in this blog post to aid in determining the specific disease in field corn. Scouting corn for the presence of disease is difficult and can be confusing since some foliar diseases appear similar to one another such as gray leaf spot and southern corn leaf blight. In addition, particular diseases are more important depending on the particular growth stage when they are encountered.
Wheat disease continue to be discussed throughout MS. Generally speaking, stripe rust has not been near the widespread threat this season as it was during the 2012 wheat crop. Scout wheat fields for the presence of diseased and relate this to the specific variety in each field when determining particular management alternatives. Keep in mind, the general cut off date for fungicides is Feekes 10.5.1.
Please see the attached information regarding the use of products that contain tebuconazole to manage wheat diseases. Note that the label restricts the overall amount of tebuconazole that can be applied to wheat in any one season to 4 fl oz/A.
Stripe rust continues to be observed throughout scattered fields in the Delta. In addition, leaf rust was confirmed in isolated cases over the past week. Keep in mind that not all fields will require a fungicide application to prevent yield loss. Scout wheat fields at this time for stripe rust hot spots (small in size = less than 3 feet in diameter; to large in size = several trucks) and determine the wheat variety present before deciding on a fungicide application.
As we move towards the soybean season we’ve included some information regarding the labeled fungicides for application to prevent yield loss as a result of soybean rust. Soybean rust was able to overwinter in several Gulf Coast states (AL, FL, LA). However, at present, soybean rust has not been detected on kudzu in MS.
Additional stripe rust has been detected throughout the MS Delta over the past two weeks. Scout fields for the presence of stripe rust to determine the extent of the infection in the wheat production area. Keep in mind that stripe rust will appear different on younger wheat plants still in the early vegetative stages than it does on more mature wheat plants.
Throughout the season many ag-related professionals ask questions about particular fungicides. More specifically, sometimes it can be confusing to determine if a particular product falls in the strobilurin class of fungicides or the triazole class of fungicides. The current update includes information to help determine the particular class of fungicides for strobilurin, triazole, and pre-mix products using fungicides labeled for application in soybean as an example.
You must provide numerous resources and management to optimize the opportunity for corn plants to produce high yields. Of course, favorable weather plays a huge role as well. This article describes areas where we can improve corn yield potential.
Deciding on a specific fungicide depends on the particular disease in the field. Also, response of a fungicide, as related to wheat yield, will depend on the particular disease, susceptibility of a particular variety, as well as the fungicide applied and at what growth stage the application is made. Results from two 2012 foliar fungicide trials are included to aid in fungicide selection. Keep in mind, that overall yield responses are the result of the fungicide’s efficacy when management the disease observed.
Stripe rust was positively confirmed in two wheat fields near Greenwood, MS on Monday, February 25, 2013. At this time, with the fluctuating environment we are observing the situation prior to making a management decision since cooler temperatures may reduce the likelihood of spread within the two fields. In addition to information regarding the current situation information is included to tell the difference between leaf, stripe, and stem rust in our production system.
This note links to four documents (pdf format), each of which lists the fungicides labeled for use on Mississippi grown peanuts as of February, 2013. The first document lists the fungicides by Trade Name. The second pdf lists the fungicides
The 2012 Row Crop Short Course will be held from December 3-5, 2012 at the Bost Extension Center on the campus of Mississippi State University. Pre-registration is free of charge until November 30 and will be $40 thereafter including at
The 2012 Delta Crop Summit will be held on Tuesday, November 13, in Stoneville, MS. Please see the attached schedule.
For the first time, strobilurin-resistant frogeye leaf spot was confirmed in MS during the 2012 season. Numerous states in our region have previously confirmed the presence of the resistant fungus.
Description and symptoms. Yesterday I looked at some defoliating fields in the greater Aberdeen vicinity. The vines looked like someone had used a set of hedge shears to remove the foliage from between the rows and thin it in the
Many diseases of soybean can produce a symptom of interveinal chlorosis. Stem canker, sudden death syndrome, Phytophthora root rot, southern blight, and several other less common diseases in the MS production system can all produce symptoms on the uppermost leaves that appear similar to SDS. However, disorders can also produce the same symptom and are oftentimes readily misdiagnosed at the field level.
Plant pathogens require a specific set of factors to occur at the same time for disease to begin. More often than not diseases require a prolonged conducive environment before the pathogen can produce observable symptoms.
Over the past six weeks soybean rust has been detected in numerous soybean fields throughout Mississippi. Even though it appears that a large number of counties have soybean plants infected with the disease, at present only low levels of soybean
As of Sunday evening, it appears that Tropical Storm Isaac will slow, turn into a hurricane, and hit our Gulf Coast sometime Tuesday. Rainfall amounts are forecast in inches below I-20 and tropical storm conditions are expected to prevail for
Foliar disease in the soybean crop continue to be observed throughout MS. Presently, soybean rust has been detected in 11 counties, with Lowndes, Noxubee, and Winston being the most current finds (8/21/2012). In addtiion, frogeye leaf spot and Cercospora blight continue to be observed across a greater number of acres.
Foliar leaf spot diseases continue to be observed throughout the MS cotton production area. Determing the particular leaf spot at the field level can be quite difficult especially if the leaf spots are a result of a foliar potassium deficiency. Bacterial blight, Corynespora leaf spot, and various other fungal diseases are being observed at present within our production system.
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