Comprehensive Guide to Corn Leaf Blight Treatment

Northern Corn Leaf Blight (NCLB) is a foliar disease of corn, caused by Exserohilum turcicum, reducing global corn yields significantly. It affects areas with cool, wet climates, including the USA, Africa, Latin America, China, and India. NCLB shows as long, cigar-like lesions on corn leaves, reducing photosynthetic efficiency and ultimately yield.

Close-up of a corn leaf infected with Corn Leaf Blight, showing small, dark, and circular lesions spread across the green leaf surface.

Managing Northern Corn Leaf Blight involves using resistant hybrids, managing residues to reduce spores, and applying fungicides during critical crop phases. Regular monitoring and prompt control procedures significantly reduce this disease’s impact on corn crops.

Yield and disease prevention are crucial in corn farming, with a focus on managing pathogens like Exserohilum turcicum, causing Northern Corn Leaf Blight. This black scourge is highly damaging, causing significant yield losses under favorable conditions like moisture and low temperatures.

Effective management includes crop rotation, resistant corn varieties, and timely fungicide application. These strategies control Exserohilum turcicum and enhance corn plant health, ensuring strong yields. Farmers can secure continuous corn yields beyond harvest by preventing diseases.

What does Northern Corn Leaf Blight Look like?

Close-up of a corn leaf affected by Corn Leaf Blight, showing numerous irregular tan lesions scattered across the leaf surface.

 Northern Corn Leaf Blight (NCLB) is identifiable for its long lesions positioned on the corn leaves that can be easily seen with just a glance. The lesions are usually less than 10 cm long and have a characteristic light-grey to brown-tan color, with the border of the lesion being darker in most cases. 

The early disease stages appear wet, then spots turn pale green and become necrotic brown or cheesy tan. At high humidity and moderate temperatures, sores rapidly increase, affecting a significant portion of the leaf surface. Extensive damage impedes photosynthesis, reducing plant vigor and potentially resulting in significant yield losses.

The blight can sometimes extend to more severe cases and lead to widespread inconspicuousness of foliage.  The leaves may appear early, and significantly damaged. This may result in drastic structural changes within the corn crop.Leaf blight causes the plant health to deteriorate and also its economic value.  Early detection and proper management are thus vital. 

Southern Corn leaf blight symptoms

  • Lesion Appearance: The most distinct symptom is the willowy, cigar-shaped lesions on the leaf with a grey to a brownish color usually being around one to six inches in length. 
  •  Early Symptoms: Initially the margins of spots can become necrotic in a fresh watery green coloration, but later they will become more similar to the characteristic necrosis. 
  •  Progression: As the disease advances, the lesions will enlarge and coalesce, being able to cover a whole great part of the leaf. This means that the photosynthetic area does decrease considerably, which then can affect the proper functioning and development of the plant. 
  •  Advanced Symptoms: In severe cases, the blight can result in damage from the leaves appearing diseased and dried with general coloration and a dying back of the leaves. 

Southern Corn leaf blight treatment

An integrated strategy that includes chemical, cultural, and biological tools is needed to cope with northern corn leaf blight (NCLB) of corn. Each method brings about inherent benefits and, when used together, provide the best outcome which could be achieved in this invasive fungal disease control endeavor.

Close-up of a corn leaf showing symptoms of Corn Leaf Blight with elongated tan lesions running parallel to the leaf veins. 

Chemical Control: 

Chemical fungicides have been in use for a long time as a primary strategy in the control of NCLB. Effective fungicides commonly have binders made up of strobilurins (a common active ingredient). g. , azoxystrobin), triazoles (e. g. The active ingredient can be a shunt (e. g. , propiconazole), a whole tissue die-out (e. g. , urea), or the combination of different modes of action. 

Use these chemicals preventatively for highest efficacy, before the disease develops, ensuring perfect timing for application. Apply chemicals at early disease stages, prior to tasseling, to match disease commencement and maximize effectiveness. Continuously observe weather conditions, especially humidity and temperature, to time control applications effectively against NCLB spread. Avoid relying solely on chemical controls to prevent resistance; integrate with other management methods for sustainable practice.

 Cultural Practices: 

Cultural control methods defray inoculum and inhibit disease spread. Crop rotation practices break the disease cycle by reducing soil spore quantities. Managing weeds through tillage decomposes infected plant debris containing fungal spores, balancing soil conservation. Resistant corn varieties effectively combat the disease. Genetically programmed corn types develop Ht genes, turning the disease harmless. Changing planting dates and densities reduces leaf wetness, hindering disease proliferation.

Biological Methods: 

Image showing Metilo and Trianum V products used to treat Corn Leaf Blight, with a corn leaf in the background displaying symptoms of the disease.

The introduction of biological controls represents one more eco-friendly modality into the NCLB control remedy. Leaf blight fungicide, Trianum V, is a biological agent that either stops fungal growth or makes the plants have a stronger resistance to biological agents. This best fungicide for leaf blight has a natural ingredient that is good for both the conventional and organic farming scenarios. Further details like usage guide and the method of application can be ascertained from the Novobac Natural Fungicide page. 

Metilo, for example, those by Novobac, on the other hand, also carry a lot of weight in disease management. These substances are boosting up plant resilience and are actually giving him less chance to have NCLB infections. Novobac’s biostimulant supports better absorption of nutrients, favorable growth environmental conditions and so the plant is more fortified to ward off infections. For more information, please visit the page devoted to Novobac Biostimulant. 

Combining these practices will not only control NCLB but also promote environmentally sustainable agriculture, benefiting both crops and environment. Consult agricultural extension services routinely to stay updated on current research, new fungal strains, and environmental changes affecting disease spread. Integrated disease management helps farmers protect crops from NCLB, ensuring higher yields and the long-term health of their fields.


  1. WANG, Shao-qing, et al. “Combined application of Trichoderma harzianum SH2303 and difenoconazole-propiconazolein controlling Southern corn leaf blight disease caused by Cochliobolus heterostrophus in maize.” Journal of integrative agriculture 18.9 (2019): 2063-2071.
  2. Limdolthamand, Supharoek, et al. “Biocontrol efficacy of endophytic Trichoderma spp. in fresh and dry powder formulations in controlling northern corn leaf blight in sweet corn.” Biological Control 181 (2023): 105217.


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