In cotton, foliar symptoms of potassium deficiency that occur before peak bloom are similar to potassium deficiency symptoms found on other broadleaf crops. Interveinal yellowing first occurs on older leaves progressing to necrotic patches developing at leaf margins as conditions worsen. In many soils potassium supply is sufficient until peak bloom. At that time rapid dry matter accumulation in bolls begins, especially when a crop is fruited properly. At this point it is difficult for the soil to supply adequate potassium to meet the increased daily demand.
Late-season potassium deficiency results in foliar symptoms that differ from early-season deficiency. During and after peak bloom, deficiency symptoms will first appear on the younger mature leaves in the upper one-third of the plant. This is primarily because the developing bolls are the stronger sink for potassium being taken up from the soil each day. These symptoms will begin as a slight interveinal yellowing that will rapidly change to a bronze-orange color. These leaves then generally curl downward and will become thick, and necrotic patches will occur at the margins. As this problem develops boll retention decreases, and premature defoliation generally occurs. These symptoms can be so devastating that symptoms of late-season potassium deficiency are sometimes mistakenly attributed to a plant disease, especially Verticillium wilt. The two symptoms are distinct and a trained eye can spot the difference immediately. Verticillium wilt causes necrotic lesions between leaf veins that have well-defined borders and will generally be a brighter yellow than will potassium deficiency; then, they develop a rich brown color. The tell tail difference will be in the discoloration of the mainstem vascular tissue. If the foliar symptoms are confusing, cut the main stem of the plant in cross section. If the stem is filled with a dark streaking discoloration, the problem is Verticilium wilt. If the vascular tissue is clean, the problem is probably potassium deficiency. A tissue test cannot always tell the difference because Verticilium wilt will plug the stem preventing proper uptake and distribution of potassium, and other nutrients throughout the plant. It is interesting to note that proper potassium fertilization has been shown to reduce the incidence and severity of Verticillium wilt.
STARKVILLE, Miss. -- Cotton leafroll dwarf virus is capable of causing significant yield loss and was reported for the first time in Mississippi earlier this year.
The implications of this disease will be a major focus of the 2019 Mississippi State University Row Crop Short Course Dec. 2-4 at the Cotton Mill Conference Center in Starkville. This course is hosted by the MSU Extension Service and Mississippi Agricultural and Forestry Experiment Station.
Parts of Mississippi’s landscape are turning white, but unlike some northern areas, this coloration is caused by cotton bolls opening for harvest, not snow accumulation.
All of Mississippi’s 2019 cotton crop has emerged, but it’s off to a slow start.
Of approximately 700,000 acres of cotton planted statewide this year, 57% is rated fair or worse by the U.S. Department of Agriculture as of July 8.
Although numbers on paper look about right for Mississippi row crops, the reality is actually quite grim in places.
HAMILTON, Miss. -- Determining the extent of tornado damage to farms in Monroe County will take weeks, but video shot from flying drones will speed up the process.
Mississippi State University Extension Service personnel have been assisting in relief efforts since the morning after an EF-2 tornado on April 13 damaged more than 140 homes in Hamilton, claiming one life and injuring 19 others.