Corn harvest is progressing very slowly across the state as the crop is taking unusually long to dry down this year. The majority of stalk rot damage in Ontario is caused by three fungi, Anthracnose, Gibberella and Fusarium. Stalk rots. Southern leaf spot Stenocarpella macrospora = Diplodia macrospora: Stalk rots, minor Cercospora sorghi. zeae, the bacterium causing stalk rot of maize in the Republic of South Africa. Stalk rot seems to show up every year somewhere. Possible sweet corn diseases that may cause stalk rot in sweet corn include Anthracnose; and less often, Fusarium and Gibberella. Leaf diseases predispose plants to stalk rots, so if a field had leaf diseases, it probably will have stalk rots… unless leaf diseases were aggressively controlled with fungicides. The corn stalk-based fiberboard made of the pretreated biomass has an increase of 3.40- and 8.87-fold in moduli of rupture and elasticity, respectively, over the fiberboard made from untreated corn stalk. Photo: Tamra Jackson-Ziems Extremely stressful growing conditions occurred during much of 2019 in Nebraska, including wet conditions early that delayed planting, record rainfall during July and August, and continued wet conditions into September. These diseases are insidious, and often growers are unaware of their effects until harvest. Management of Diplodia stalk rot is through use of resistant hybrids, balanced soil fertility, appropriate plant population for the hybrid selected, and crop rotation. Generally though, most stalk rots will show up later in the season. Losses due to stalk rot vary from field to field and from one hybrid to another. Corn stalk rots and lodging are usually the result of an interaction between weather,fertility, compaction, leaf disease, plant population, planting date, and kernel fill. Most of the corn across the state is nearing or at black-layer, which means it is time to scout fields for stalk rots in an effort to evaluate standability and plan a successful harvest. Symptoms of stalk rots are frequently first noted on early maturing varieties and on corn stalks producing two ears. Erwinia carotovora f. sp. In contrast to fusarium stalk rot, gibberella stalk rot has small, round, black specks called perithecia near the nodes that can be easily scraped off. Some surface discoloration, especially around the nodes, may be noted. Sun SQ, Yang XR, and Tian T. Study on inoculation method of corn stalk rot resistance identification. Gibberella stalk rot Corn Internal shredding of lower nodes; pink-to-red internal discoloration Same as for Fusarium stalk rot. 2017; 66:1267–1275. Anthracnose (Colletotrichum graminicola). In addition, to anthracnose stalk rot, we are also seeing Gibberella stalk rot picking up . Root and crown rots developing in corn after the seedling stage are usually caused by Fusarium spp. Blog Post. Anthracnose stalk rot is a significant pathogen of corn throughout the U.S., causing losses through physiological effects on yield and through stalk lodging. Pauer GD, 1964. These diseases also can impact yield if corn plants are killed prematurely. Leaf spot. Among these groups, fungal diseases are the most widespread. By Alison Robertson, Department of Plant Pathology It's hard to believe the growing season is almost over. 6. Conditions favoring this disease include warm humid weather especially when corn follows corn. Also find out if these common corn ear rots have the potential to produce mycotoxins. Occurrence in South Dakota of a bacterial stalk rot of corn caused by Erwinia chrysanthemi. Banded leaf and sheath blight. This project will develop new sources of anthracnose stalk rot resistance in corn for use by the seed industry. Anthracnose stalk rot is typically worse in fields in a corn-on-corn rotation, and/or no-tilled, and planted to a susceptible hybrid. Corn stalk lodging and rot. Ear rot. Corn smut. To assess for corn stalk rots, gently push at least 10 corn stalks to an angle of 45o at a … Leaf rust. Anderson is the ISU Extension field agronomist for central Iowa. In contrast to fusarium stalk rot, gibberella stalk rot has small, round, black specks called perithecia near the nodes that can be easily scraped off. Several fungi and bacteria can cause stalk rots both earlier and/or later in the season. Read the article Drought and derecho increase mycotoxin risk in 2020 Iowa corn crop-scouting and monitoring fields . Fusarium episphaeria Fusarium merismoides Fusarium oxysporum Fusarium poae Fusarium roseum Fusarium solani This will aid in making assessments about field harvest order and if there is a risk of mycotoxin contamination. Although these fungi cause different symptoms, their ultimate effect on the corn plant is the same. Stalk rots are one of the most significant set of diseases on corn. There are a number of plant pathogens that can cause stalk rot including, Anthracnose, Bacteria, Charcoal, Diplodia, Fusarium, Gibberella, and Pythium. Severity of the disease changes from year to year due to several factors conditions. Anthracnose stalk rot of field corn. Bacterial stalk rot of corn is favored under conditions of high air temperatures and wet weather or high humidity. Plant Disease Reporter. Stalk rots may cause lodging, especially if the affected crop is not harvested promptly. Scout Corn Fields for Stalk Rot. Main emphasis of Pioneer research concerning this disease include Corn stalk rot is one of the most destructive corn diseases worldwide, which causes maize lodging and reduces grain weight and yield. Stalk Rots Showing Up in Some Corn Fields Corn harvest is progressing very slowly across the state as the crop is taking unusually long to dry down this year. Stalk rots may be prevalent in fields that have too much nitrogen coupled with extended periods of wet weather after silking. They reduce grain fill, stalk integrity, and accelerate senescence. Southern corn leaf blight and stalk rot Cochliobolus heterostrophus. Otta J D, Wood L S, 1977. The challenges of this growing season continued this month when a storm front brought more than 3 … The longer the crop stays in the field, there greater the risk of late-season diseases such as ear and stalk rots, especially if it continues to rain. Losses in certain years reach 10 to 20 percent or more of the expected yield. Pathogen Fusarium stalk rot of corn, the most common corn stalk rot in Nebraska, is caused by several species, Fusarium verticilliodes e J. Sheld. Bacterial stalk rot is not common but often shows up with overhead irrigation of corn, especially where the water source is a lake, pond, or slow-moving stream. 61 (7), 536-537. able attention. Low levels of stalk rot occur in nearly every corn field in Delaware, and … The time has come to start scouting corn for ear and stalk rots. Stalk rot diseases and the pathogens that cause them are common in corn. A few corn fields scouted in Brookings County were found with Fusarium root rot at low levels. These diseases reduce annual yields by a minimum of 5 percent. Bacterial stalk rot Corn Collapsed, twisted stalk with a foul odor High rainfall, or flood prone areas; temperatures of 86 to 95°F and poor air circulation Downy Mildew In: South African Journal of Agricultural Science, 7 581-582. Gibberella stalk rot is distinguished by the pink to reddish coloration of disintegrated pith tissue and root crowns that are often discolored and severely rotted (Figure 2). consider Diplodia stalk rot as either an air-borne or a soil borne disease. However, Diplodia and Pythium have also been observed. Infected plants were wilting and upon splitting of the lower nodes revealed brown discoloration of the pith. Stalk rot typically reduces maize output by 10.0% and may increase to 30.0% to 50.0% in serious cases . Reports and observations of lodging are starting to come in. September 18, 2020 11:06 AM. Various stalk rot diseases have been confirmed in samples from corn fields across Nebraska. It is more severe where corn follows corn. Corn stalk rot is a family of diseases caused by several species of fungi and bacteria. Gibberella stalk rot is distinguished by the pink to reddish coloration of disintegrated pith tissue and root crowns that are often discolored and severely rotted (Figure 2). stalk rot. Bipolaris maydis [anamorph] = Helminthosporium maydis. View Article Google Scholar 27. They can weaken corn stalks, leading to stalk lodging and harvest difficulties for producers (Figure 1).