Foliar diseases of soybean continue to be observed throughout the state. At present, no soybean rust has been detected in Mississippi. However, aerial web blight, downy mildew, frogeye leaf spot, and target spot have all been observed in light to severe situations depending on field location.
Corn is not immune to yield loss until physiological maturity occurs. However, it is not nearly as vulnerable during late reproductive stages. This article includes a chart which should substantially help assess the risk of potential corn yield reduction during late reproductive stages.
Additional bacterial blight has been observed in the MS cotton production system. At present, 12 counties have been reported to contain infected cotton.
Foliar corn diseases continue to be observed throughout MS. Even though common rust, gray leaf spot, northern corn leaf blight, and southern corn leaf blight continue to be observed at low levels, additional diseases have been encountered over the past two weeks.
Numerous fungicide trials were conducted during the 2013 season to determine the effectiveness of some popular commercially available fungicides on managing frogeye leaf spot. Attached find data as related to some R5 and one R5.5 fungicide application on a frogeye leaf spot susceptible Maturity Group IV variety in Stoneville (4 trials) and Starkville (1 trial).
Several new fungicide products are commercially available for soybean productions systems this season. Affiance, Aproach, Aproach Prima, Cercobin, Equation, Fortix, Incognito (4.5F and 85WDG), Overrule, Topsin XTR, and Viathon all have labels for soybean production systems and may be marketed throughout MS for application to soybean plants. Rates, pre-harvest intervals, as well as the active ingredients and links to the full label are included.
Once again, bacterial blight has been observed in the MS cotton crop. At present, several fields in the south and north Delta as well as a single field in east MS have been observed to contain bacterial blight infected cotton leaves. To date (July 8, 2014), a single cotton variety has been reported to be infected in all fields.
Sentinel plots were planted in the spring of 2014 to serve as a source of soybean plants for monitoring important, potentially yield-limiting soybean diseases throughout MS. The sentinel plot network has protected MS soybean farmers for 9 years now. With financial aid from the Mississippi Soybean Promotion Board and the United Soybean Board, the sentinel plots will be scouted for the remainder of the 2014 season.
Foliar corn diseases continue to be observed throughout the MS corn crop. Common rust, gray leaf spot, northern corn leaf blight, and southern corn leaf blight are all present at low levels throughout the Delta. As of Wednesday (June 25, 2014), southern corn rust had only been observed in southeastern MS (Forrest, George, Greene, Jackson, Perry, and Stone counties).
Frogeye leaf spot management continues to be a hot topic during the 2014 season. Scattered reports of frogeye in R3+ soybean fields continue to be made. Most of the questions at this time tend to be regarding fungicide management suggestions at the R3/R4 application timing. Knowing what varieties are planted in fields is one of the most important determining factors since susceptible varieties should be managed differently at R3/R4 than frogeye tolerant varieties.
To date this has been a fairly light corn disease year. However, some lesser observed diseases, such as anthracnose leaf blight can be observed on the lowest leaves in some corn fields. Common rust, northern corn leaf blight, and to a much lesser extent southern corn leaf blight can also be observed in some corn fields.
A corn, cotton, peanut, and soybean field day is scheduled for June 17th at the Delta Research and Extension Center in Stoneville, MS. The general theme of the field day will include pertinent information for mid-season row crop issues.
Maintaining nitrogen applied as a pre-flood application is an important topic for rice farmers. Nitrogen can be lost by at least three different methods, two of which are considered to be bad since the N will become unavailable for plant uptake.
A little rice has started to go to flood in Mississippi this week and that means it is time to start thinking about rice water weevil. Overall, the majority of the crop is behind because of all of the rain that we have had across the Delta over the last several weeks. In general, the rice that is currently being flooded was some of the earliest planted. As a result, the early rice has endured a lot of rainfall and adverse conditions.
The dates for the 2014 Scout Schools have now been set. We will be providing detailed information on identification, biology, thresholds, and management of the major insect and disease pest of Mississippi row crops. These trainings can also be used to renew your insect and disease consultants license and CEU’s for Certified Crop Advisors will be provided at each. The meetings will also serve as In-Service training opportunities for MSU-ES agents as well. These trainings are great for the experienced and the inexperienced.
A substantial number of soybean acres have been reported to be affected by seedling disease. However, the majority of the field seedling issues can be blamed on poor environmental conditions following the planting that occurred around Easter (between April 14 and 19) and some of the residual herbicide products applied.
Even though additional foliar wheat diseases have been observed throughout MS, I still consider this to be one of the cleanest wheat crops I have seen. At present, extremely low levels of leaf rust have been observed in two locations, stripe rust on a few protected plants in Stoneville, Septoria leaf blotch, glume blotch, and tan spot have all been reported in the MS wheat crop.
Before the rice season gets into the full swing, consider several important fungicide application strategies before the mid-season fungicide application. Preventing fungicide-resistance from developing is the first step in managing the issue.
Decisions to apply a fungicide to wheat should be based on the specific variety planted, response of the particular variety to foliar diseases that could impact yield, growth stage at time of decision, and whether or not the environment has been conducive for disease development. At present, foliar disease that could reduce yield have not been observed in commercial wheat fields.
Many people ask why continue mundane planting date research don’t we have enough. Truth is, when talking about items such as planting date, and soil testing data that will be modeled, there is never enough data. The more data you
Wheat diseases remain extremely scarce throughout the MS wheat production system to date. No leaf rust, stripe rust, or Septoria have been observed to my knowledge. However, bacterial leaf streak has become a regular observation in most wheat fields.
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.
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.
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.
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.
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