Crown Rot

Overview

Crown rot is a significant fungal disease affecting a variety of crops in the US and Canada, including wheat, barley, and various legumes. The disease is primarily caused by Fusarium species, which thrive in warm, moist conditions.

Crown rot infects the base of the plant, leading to browning and decay of the crown and root tissues. This infection disrupts the plant's ability to transport water and nutrients, resulting in stunted growth, reduced tillering, and ultimately lower yields. In severe cases, it can cause plant death.Management of crown rot involves integrated strategies, including crop rotation, resistant varieties, and fungicide applications.

Two fungicides that may be effective against crown rot are Thiophanate-methyl 4.50 Value Pick and Willowood Teb 3.6SC, both available from FBN. These fungicides can help manage the disease when used as part of a comprehensive disease management plan. Early detection and timely intervention are crucial to minimizing the impact of crown rot on crop production.


How to Identify Crown Rot

Identifying crown rot in crops involves careful observation of several specific symptoms and signs. Here’s a detailed guide to help farmers recognize this disease:

  1. Initial Symptoms:

    • Discoloration: Look for a light brown to dark brown discoloration at the base of the stem, just above the soil line. This is often the first visible sign of crown rot.

    • Lesions: Check for lesions or necrotic spots on the lower stem and crown area. These lesions may expand and coalesce, leading to extensive browning.

  2. Plant Growth:

    • Stunted Growth: Affected plants often exhibit stunted growth compared to healthy plants. They may appear shorter and less vigorous.

    • Reduced Tillering: In cereals like wheat and barley, crown rot can cause a noticeable reduction in the number of tillers (side shoots).

  3. Root System:

    • Root Decay: Dig up a few plants and examine the root system. Infected plants typically have a decayed or rotted root system, which is often brown and brittle.

    • Poor Root Development: The roots may be poorly developed and show signs of necrosis.

  4. Foliage Symptoms:

    • Yellowing and Wilting: The leaves of infected plants may turn yellow and wilt, especially during periods of water stress.

    • Premature Senescence: In severe cases, the entire plant may die prematurely, leading to early senescence.

  5. Field Patterns:

    • Patchy Distribution: Crown rot often appears in patches within a field, rather than uniformly. These patches may correspond to areas with poor drainage or previous crop residues.

  6. Microscopic Examination:

    • Fungal Structures: For a definitive diagnosis, collect samples and send them to a diagnostic lab. Under a microscope, the presence of Fusarium spores and mycelium can confirm crown rot.

  7. Environmental Conditions:

    • Weather Patterns: Consider recent weather conditions. Crown rot is more prevalent in warm, moist environments, especially following wet springs and dry summers.

By closely monitoring these symptoms and considering environmental factors, farmers can accurately identify crown rot and take appropriate management actions. Early detection is crucial for effective control and minimizing yield losses.

Geographic Impact of Crown Rot

Crown rot has a significant geographic impact, affecting various regions across the United States and Canada, particularly in areas where environmental conditions favor the disease. Here’s a detailed look at its geographic impact:

United States:

  1. Great Plains:

    • States Affected: Kansas, Nebraska, Oklahoma, Texas.

    • Crops: Wheat and barley are major crops in this region, and crown rot is a common issue due to the warm, dry conditions that can follow wet springs.

  2. Pacific Northwest:

    • States Affected: Washington, Oregon, Idaho.

    • Crops: This region is known for its wheat and barley production. The disease thrives in the cool, wet springs followed by dry summers typical of this area.

  3. Midwest:

    • States Affected: North Dakota, South Dakota, Minnesota.

    • Crops: Wheat, barley, and legumes are commonly affected. The disease can be exacerbated by the region's variable weather patterns.

  4. Southern States:

    • States Affected: Arkansas, Louisiana, Mississippi.

    • Crops: Corn and soybeans are also susceptible to crown rot, especially in the warm, humid conditions prevalent in these states.

Canada:

  1. Prairie Provinces:

    • Provinces Affected: Alberta, Saskatchewan, Manitoba.

    • Crops: Wheat and barley are major crops here. The disease is a significant concern due to the region's dry summers following wet springs.

  2. Eastern Canada:

    • Provinces Affected: Ontario, Quebec.

    • Crops: Corn and soybeans are commonly affected. The disease can be problematic in the humid conditions typical of this region.

Environmental Conditions:

  • Temperature: Crown rot is more prevalent in regions with warm temperatures, particularly where there are significant temperature fluctuations between seasons.

  • Moisture: Areas with wet springs followed by dry summers are particularly susceptible, as the initial moisture promotes fungal growth, and the subsequent dryness stresses the plants, making them more vulnerable.

Timing of Crown Rot Impact

Crown rot typically emerges and impacts fields across the United States at specific times of the growing season, influenced by environmental conditions and crop growth stages. Here’s a detailed timeline of when crown rot is most likely to emerge and affect fields:

Emergence and Initial Infection:

  1. Spring (Planting to Early Growth):

    • Conditions: Crown rot fungi, primarily Fusarium species, thrive in moist soil conditions. Wet springs provide an ideal environment for the initial infection.

    • Infection Timing: The fungi infect the seedlings and young plants during the early growth stages, particularly from planting through tillering in cereals like wheat and barley.

Disease Development:

  1. Late Spring to Early Summer (Vegetative to Early Reproductive Stages):

    • Conditions: As temperatures rise and soil moisture levels fluctuate, the disease begins to develop more aggressively. Warm, dry conditions following a wet spring can stress the plants, making them more susceptible to the disease.

    • Symptoms: Initial symptoms such as browning at the base of the stem and reduced tillering become more noticeable during this period.

Peak Impact:

  1. Mid to Late Summer (Reproductive to Maturity Stages):

    • Conditions: The disease reaches its peak impact during the reproductive stages of the crop, including heading and grain filling in cereals.

    • Symptoms: Severe symptoms such as stunted growth, yellowing and wilting of leaves, and premature senescence are most evident. The root system may show significant decay, and the overall plant health deteriorates.

    • Yield Impact: This is the critical period when crown rot can cause substantial yield losses, as the disease interferes with nutrient and water uptake during the crucial grain-filling stage.

How to Manage Crown Rot

Farmers can manage crown rot in various crops through an integrated approach that includes cultural practices, crop rotation, resistant varieties, and the use of fungicides. Here are some specific strategies and examples of chemical products available for purchase from FBN:

Cultural Practices:

  1. Crop Rotation: Rotate crops with non-host species to reduce the buildup of Fusarium pathogens in the soil.

  2. Residue Management: Remove or deeply incorporate crop residues to minimize the source of inoculum.

  3. Proper Irrigation: Avoid over-irrigation and ensure good drainage to reduce soil moisture levels that favor fungal growth.

Resistant Varieties:

  • Plant Resistant Varieties: Use crop varieties that are resistant or tolerant to crown rot to reduce disease incidence and severity.

Fungicide Applications:

  1. Fortuna™ 75 WDG Fungicide:

    • Active Ingredient: Mancozeb

    • Crops: Labeled for use on wheat, barley, and legumes.

    • Usage: Apply

      Fortuna™ 75 WDG Fungicide to protect crops from crown rot. It is effective in preventing the disease when used as part of a comprehensive management plan.

  2. Thiophanate-methyl 4.50 Value Pick:

    • Active Ingredient: Thiophanate-methyl

    • Crops: Based on similarity with labeled products, it may be labeled for use on wheat, barley, and legumes.

    • Usage: Thiophanate-methyl 4.50 Value Pick can be used to manage crown rot by applying it during the early growth stages to protect young plants from initial infection.

Timing and Application:

  • Early Detection: Monitor fields regularly for early symptoms of crown rot and apply fungicides at the first sign of disease.

  • Application Timing: Fungicides should be applied during the early growth stages, particularly from planting through tillering in cereals, to protect the plants from initial infection.

By combining these strategies, farmers can effectively manage crown rot and minimize its impact on crop yields.

Every product that labels CROWN ROT as a weed, pest, or disease the product can be applied against is shown below. Click any product for label and more information.
A-Zox 25SCA-Zox 50WDGAbound® Flowable FungicideAcadia™ 2 SCAcadia™ 2 SCAce™ 3.8L STActinovate® AGActinovate® AGAframe™Aliette® WDG FungicideAmeriCop 40 DFAppear®Appear® IIAproach®Arius™ 250Azaka™AzoxyStar®Azoxystrobin SCBadge® SCBadge® SCBadge® SCBadge® X2Badge® X2Badge® X2Basic Copper 53Captan Gold® 80WDGCercobin® FungicideCercobin™ FungicideChamp® Dry PrillChamp® Formula 2 FlowableChamp® WGChampion® Wettable PowderChampION++™ Fungicide/BactericideCop-Kleen™Copper-Count®-NCruiserMaxx® PeanutsCueva® Fungicide ConcentrateCuprofix® Ultra 40 Disperss®Cuproxat® FLCuproxat® Flowable Copper FungicideDelaro® 325 SC FungicideDexter® SCDithane® F45 Rainshield® FungicideDithane® M45 FungicideDouble Nickel 55™Double Nickel® LCEagle® 20EW Specialty FungicideEagle® 40WP Specialty FungicideEcoSwing® Botanical FungicideEmpireEquation™ SC FungicideEverGol® EnergyFlint® ExtraFortuna™ 75 WDG FungicideFungi-Phite® FungicideGCS Azoxy 2SCGold Rush®Guarda®Helena® T-Methyl 4.5 AgHowler® EVOHowler® FungicideIncognito® 4.5 FInsignia® fungicideInsignia® SC Intrinsic® brand fungicideKentan® DFKocide® 2000Kocide® 2000Kocide® 2000-OKocide® 3000Kocide® 3000Kocide® 3000-OKocide® DFKOP-Hydroxide™KOP-Hydroxide™ 50WKOP™-5 Algaecide/Bactericide/FungicideKoverall® FungicideKoverall® FungicideManKocide®Manzate® MaxManzate® Pro-Stick™ (UPI)MasterCop®Mazolin™Miramar™ FungicideNordox®Nordox® 75 WGNu-Cop 50 WPNufarm T-Methyl 4.5 F FungicideOrkestra™ Intrinsic® brand fungicideOrondis®Orondis® Gold (Premix) FungicideOrondis® Gold 200OxiDate® 2.0OxiDate® 5.0OxiDate® Broad Spectrum Bactericide/FungicideOxiPhos®Pageant® Intrinsic® brand fungicidePenncozeb® 75DFPenncozeb® 80WPPeroxySan-CX Broad Spectrum Bactericide/FungicidePh-D®Ph-D®Phoenix Siskin®PompaPrevisto®Pristine® fungicideProzio™ SCQuadris® FlowableRancona® 3.8 FSRancona® CrestRancona® Crest WRRancona® CTSRancona® V 100 Pro FSRancona® V 100 Pro FSRancona® V RTU FSRanman®Reckoning FungicideReCon™ Bold SLRedigo® 480Regev®Rendition™Resist 57™Revytek™ fungicideRidomil Gold® SLRoper® DFRoper® DF Rainshield™Satori® FungicideSegway® FungicideSegway® Fungicide SCSegway® OSerenade® ASOSerifel® BiofungicideSparra™Spectro® 90 WDGStamina® F4 Cereals fungicide seed treatmentSubdue® GRTalaris™ 4.5 FTeraxxa™ F4 Seed TreatmentTerrazole® 35% Wettable PowderTerrazole® CATetraban®Tetraban® FungicideTimorex Act®Topsin® 4.5FL FungicideTopsin® M WSB FungicideTrevo®Triathlon® BATrinity® fungicideUniform®Velum®Velum® OneVelum® PrimeWarden® Cereals HRWillowood Azoxy 2SCXyway™ 3D FungicideXyway™ LFRZeroTol® 2.0