In descending order, by date published.
12/13/2022 (major revision)
Authors: Carl Bradley, J.D. Green, John Grove, Greg Halich, Erin Haramoto, Cam Kenimer, Carrie Knott, Chad Lee, Travis Legleiter, Sam McNeill, Michael Montross, Hanna Poffenbarger, Dan Quinn, Edwin Ritchey, Montse Salmeron, Jordan Shockley, Tim Stombaugh, Raul Villanueva, Ole Wendroth, Kiersten Wise
Corn is a summer annual crop that is grown widely across Kentucky, the United States, and around the world. In the United States, field corn is grown on about 85 million acres (34 million hectares) while sweet corn is grown on about 600,000 acres (240,000 hectares) and popcorn is grown on about 200,000 acres (81,000 hectares). Most of the field corn across the United States is yellow dent corn. In Kentucky, both yellow dent corn and white dent corn are grown. Corn acres in Kentucky peaked at 3.85 million in 1917 and have been around 1.2 to 1.5 million acres since the 1970s (USDA-NASS, 2020). Most corn in Kentucky today is grown in minimum tillage or no-tillage conditions. Most corn acres are rotated with soybean or wheat and double-crop soybeans.
Authors: Kiersten Wise
Foliar fungicide applications occur commonly in corn to manage foliar diseases such as gray leaf spot. University of Kentucky research indicates that the most effective application timing for both foliar disease control and yield benefits is at tasseling/early silking (VT/R1). Because of the height of corn at this growth stage, these applications are typically applied aerially, with fixed wing or helicopter aircraft. However, many Kentucky fields are small, surrounded by trees or other obstacles to aircraft, meaning that fungicide application is not an option in these areas.
Corn seeds and seedlings are susceptible to infection by a number of soilborne fungi. When planted into cool, wet soils, seeds may decay before or after germination. Affected plants that survive past the seedling stage may go on to produce an ear if nodal roots develop normally, although stunting and reduced ear size can occur as a result of seedling diseases. Severely affected plants may die during stressful weather as the result of an inadequate root system.
Blackpatch is an important fungal disease of forage legumes in Kentucky. A metabolite produced by the fungus can result in slaframine toxicosis or "slobbers" in many animals. The fungal disease was first reported in Kentucky in 1933 on red clover. Most Extension literature associates blackpatch and slaframine with red clover, which is very susceptible to the disease. However, many forage legumes including alfalfa can be infected by the causal fungus.
Drone technology has improved in recent years and has also become more accessible. In Kentucky, commercial drone fungicide application is now an option in several areas. Drones specifically designed to apply products can potentially be used to apply fungicide in fields that are not accessible to other aircraft. This publication describes experiments to determine if drone fungicide applications can reduce foliar diseases in corn and discusses factors to consider when using drone technology to apply fungicides.
Northern corn leaf blight (NCLB) is a significant foliar corn disease in Kentucky. This disease has been damaging in the United States Corn Belt since the early 1900s, but has increased in severity and prevalence throughout the U.S., including Kentucky. This publication describes the symptoms and signs of NCLB, conditions that favor disease development, and management methods to reduce impact on yield.
A quick resource on grain crop production.
A quick resource on grain crop production. NOTE: This poster is 25 x 38 inches. ID-268 is the booklet-sized version.
Curvularia leaf spot is a corn disease that was reported for the first time in the United States in Louisiana in 2017, and was confirmed in Kentucky in 2018. While the impact of Curvularia leaf spot in Kentucky is not yet known, this disease causes yield loss in tropical areas, and is considered to be one of the most important diseases of corn in China. This publication describes the symptoms and cause of disease, conditions that favor disease development, and foliar diseases that have similar symptoms.
Diplodia leaf streak of corn is a disease that has become more prevalent in Kentucky in recent years. It is commonly observed in fields in western Kentucky and is easily confused with other corn foliar diseases. Small, round, dark brown-to-tan lesions are first observed on leaves. Dark concentric rings may be observed in the center of early lesions at the infection site on the leaf. These lesions expand lengthwise in long streaks from the infection point and form elongated elliptical lesions. In severe cases, lesions can coalesce to blight large areas of affected leaves.
Authors: Ric Bessin, Carl Bradley, J.D. Green, John Grove, Greg Halich, Erin Haramoto, Carrie Knott, Chad Lee, Travis Legleiter, Josh McGrath, Sam McNeill, Javier Reyes, Edwin Ritchey, Montse Salmeron, Jordan Shockley, Claire Venard, Raul Villanueva, Ole Wendroth, Kiersten Wise, Xi Zhang
This publication provides information on soybean growth and development, principles of variety selection, and management practices to maximize soybean profitability in Kentucky.
During spring, several leaf spotting diseases--including Leptosphaerulina (Lepto) leaf spot and spring black stem/leaf spot--are common in alfalfa. Leaf spotting diseases result in distinct round to elongated spots that sometimes have a dark margin. Very wet weather in spring and early summer favor activity of leaf spotting diseases in first and second cuttings. Wet and humid weather during summer favor other leaf spotting and blighting diseases. All leaf spots and blights weaken plants, but alfalfa often outgrows the damage in later cuttings. Maintain a regular cutting schedule, cutting at 30- to 35-day intervals.
Physoderma brown spot can be a striking foliar disease that is periodically observed in field corn in Kentucky. This publication describes the symptoms and cause of disease, conditions that favor disease development, and options for disease management.
Diplodia ear rot can reduce yield and grain quality by damaging kernels, lowering grain test weight, and reducing grain fill. Incidence of affected ears in the field can vary from 1% or 2% to as high as 80%. Although mycotoxins have been associated with Diplodia ear rot in South America and South Africa, there have been no reports of livestock feeding issues due to mycotoxins linked to Diplodia ear rot in the United States.
Holcus leaf spot, a bacterial disease, can be seen sporadically in Kentucky cornfields, and it is challenging to diagnose. This publication describes the disease symptoms, conditions that favor disease, and how to distinguish holcus spot from herbicide injury that can mimic this disease.