Over the past few weeks numerous maladies have been observed in corn that don’t require a management decision. One of our more common issues, purple leaf sheath, is simply present under the right environmental conditions and when nutrients become available for the organisms that produce the minor staining on the corn plant.
Scouting corn can be especially challenging. Looking for disease within the corn canopy can take a tremendous amount of time and should be done a little different depending on the particular crop stage encountered. Once an ear has set (post-tassel) focusing on the ear leaf and above is generally the best scouting method since protecting the ear leaf is important. I’ve included several descriptions and pertinenent information regarding some of the more commonly encountered diseases in our corn production system.
Over the past week a few soybean fields in the Delta have been observed with the characteristic symptoms and signs of southern blight. Typically, southern blight is a disease of rare occurrence; however, the prevailing environmental conditions seem to be causing added stress and increasing the incidence of this particular disease.
The corn crop appears to be much earlier this year than it has over the recent past. I’ve driven by numerous fields from south Washington County to north Bolivar County where almost 100% of the field has reached the tasseling
There have been a lot of questions recently about thrips control in peanuts. In general, thrips will not hurt peanut yields except in EXTREME situations. Peanut seedlings are relatively vigorous compared to most of the crops grown in Mississippi. Foliar insecticide applications, though rarely needed, should be based on plant injury rather than thrips numbers.
Environment is the key component in the expression of every plant disease. Especially when considering the occurrence of seedling diseases we typically have a situation in place where inoculum is present in the soil, more than likely in high quantities,
Holcus leaf spot, a leaf spot of corn caused by a bacterium, has been confirmed across a wide geographic area in the Mississippi Delta over the past two weeks. The disease is typically characterized by numerous cream to white lesions on the corn leaf that can oftentimes be confused with herbicide (paraquat) drift.
In addition to the wheat rusts we’ve been observing over the past few months throughout our wheat production area, numerous additional foliar disease have been observed. The abnormally warm temperature and heavy dews we’ve experienced over the past several weeks have allowed several other wheat diseases to occur.
Sentinel plots will continue to be used to monitor for yield-limiting diseases throughout MS during the 2012 season. Even though in the past sentinel plots have more typically been used to monitor for the presence of soybean rust, the plots will be used to monitor for all economically important soybean diseases.
Heavy leaf and stripe rust sporulation continues to be a concern throughout much of the wheat production area in MS.
Wheat diseases continue to be identified throughout the MS production area. Barley yellow dwarf virus, leaf rust, powdery mildew, and stripe rust are all present in limited situations in several counties.
Over the past two weeks the reports of both stripe and leaf rust of wheat have increased in MS. The following blog article provides information regarding the developing situation. The continued unseasonably warm environmental conditions may contribute to an increase in stripe rust severity this season.
Stripe rust was detected in a Bolivar County wheat field last Monday morning (January 30, 2012). The report is the first of stripe rust from MS in 2012 and the second report of the disease from wheat east of the Rocky Mountains.
Severe Cercospora blight coupled with cooler temperatures as will as a cool north wind worked to defoliate soybean plants prematurely following Tropical Storm Lee.
Since the middle of July, numerous fields have been confirmed to have cotton plants infected with the bacterium that causes bacterial blight. The majority of the cotton fields were contained within a few counties in the Delta (Bolivar, Coahoma, Leflore, Quitman, Sunflower, Tallahatchie, Washington), and a low number of exceptions outside of the Delta (Calhoun, Grenada, Monroe, Yalobusha). The organism that causes bacterial blight has the potential to overwinter on cotton stubble left standing in the field.
The information included in this blog update originated from the soybean rust telephone conference held on August 29, 2011.
Damaged grain sorghum panicles can allow many different fungi to enter and infect the developing grain or simply allow the fungus a place to reproduce if a kernel has been removed from the panicle itself. A similar situation can occur
Well, it is that time of year again. Seems over the past 5 seasons we begin to encounter foliar cotton diseases during this particular week in August. 2011 appears to be the year when the majority of these leaf spots are the worst they’ve been compared to the previous 4 seasons.
The link for the Cotton Defoliation Videoconference that took place on August 26, 2011 is provided.
This is the time of the year when I tend to get a ton of telephone calls regarding the presence of rotten (moldy) corn ears. Over the past few weeks I’ve observed a range of symptoms on corn ears. In extreme cases the entire ear was covered with fungal growth and corn kernels were beginning to sprout but in the less severe cases only the tip was covered with fungus. Many fungi can inhabit a corn ear and in some cases the specific fungus present will depend on health of the corn plant, whether or not the ear has sustained any damage (insect or otherwise), how far the ear filled out, previous crop in the field, length of time in the field past physiological maturity, plant stress and duration of the stress during the season, and environmental conditions.
Bacterial blight (or angular leaf spot) continues to be the hot topic in cotton production even at this late stage in the season. With continued temperatures between 86 and 97°F as well as scattered rainfall throughout much of the state it is likely that bacterial blight will continue to defoliate plants and infect bolls.
Southern MS On Monday and Tuesday (August 8 & 9) the soybean disease scouting crew made a tour through southern MS to scout soybean sentinel plots as well as commercial fields and kudzu. Little if any disease was identified; however,
Currently, a trial is underway in Stoneville, MS to determine the impact of bacterial blight on the yield of some of the more commonly planted cotton varieties in MS.
Soybean scouting continues throughout MS for foliar diseases. Over the past week to ten days, aerial web blight has been identified in several fields in eastern and northeastern MS. However, aerial blight has not been identified in the Delta and seems
Over the past 7 days, numerous cotton fields have been determined to be infected with bacterial blight, caused by Xanthomonas axonopodis pv. malvacearum (formerly Xanthomonas campestris pv. malvacearum). In addition to the growing number of acres in MS having been
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