Leaf Blight in Maize: Causes, Symptoms, and How to Control it

This blog covers the critical aspects of leaf blight in maize, offering insights into its causes, symptoms, and solutions for managing the disease.

What is Leaf Blight of Maize ?

Identifying leaf blight in maize can be tricky as several fungal diseases show similar symptoms. However, here are some key points:

• Look for the size and shape of the lesions on the leaves. Are they large and oval, elongated and elliptical, or small and round.
• Note the color of the lesions and any surrounding halos. Are they brown, reddish-brown, gray, or cinnamon-brown?
• Distribution: Observe where the lesions appear on the leaves. Do they start from the bottom and move upwards, or are they spread more randomly?

Overview of Leaf Blight in Maize

Type of Infestation	Disease
Common Name	Leaf Blight
Scientific Name	Exserohilum turcicum & Helminthosporium maydis
Category of Plant Disease	Fungal Disease
Mode of spread	Wind borne spores, rain splash
Affected parts of plant	Leaves

Favorable factors for Leaf Blight in Maize:

• Moderate temperatures (20-30°C): Most leaf blight fungi flourish in warm weather, with optimal temperatures ranging from 20 to 30°C. This coincides with the vegetative and reproductive stages of maize, making it more susceptible to infection.
• High humidity (above 90%): Fungal spores require moisture to germinate and infect plant tissues. Humid environments, including extended periods of dew or rainy weather, favor spore germination and disease spread.
• Wind: Wind plays a crucial role in dispersing fungal spores over long distances and facilitating secondary infections within a field.

 

Initial Symptoms of Leaf Blight in Maize:

• Small, discolored spots or lesions: Appear on the lower leaves first, often with subtle changes in color like faint yellowing, brown specks.
• Limited leaf damage: Initially, the lesions might be isolated and only affect a small portion of the leaf surface.
• Stunted growth: Slight stunting compared to healthy plants.

Severe Symptoms of Leaf Blight in Maize:

• Large Expanding lesions: As the disease progresses, the lesions will enlarge and become more prominent, often changing color to become brown, gray, or reddish-brown.
• Coalescing lesions: In severe cases, multiple lesions may merge, covering large areas of the leaf surface and causing significant blighting.
• Premature leaf death: Infected leaves may turn yellow, wilt, and eventually die off prematurely, leading to defoliation.

Control measures for Leaf Blight in maize:

Biological method of control for Leaf Blight in Maize

Application of Biocontrol Agents: Utilize beneficial microorganisms like Trichoderma spp. and Bacillus subtilis, which are known to suppress the pathogens causing leaf blight. These biocontrol agents work by outcompeting the harmful pathogens or directly antagonizing them, reducing the disease's impact on maize crops.

Enhancing Soil Health: Incorporate well-decomposed compost or organic matter into the soil. This not only improves soil fertility but also promotes a healthy population of beneficial microbes, which can naturally help control the spread of leaf blight in maize.

Chemical method of control for Leaf Blight in Maize

Apply these recommended fungicides to manage leaf blight in maize and ensure healthy plants

Product	Technical name	Dosage
K-ZEB	Mancozeb 75% WP	500gm per Acre.
COC 50	Copper oxychloride 50 % wp	2gm/ltr
STRIKER	Pseudomonas Fluorescens 1% WP	1 liter per acre
DR BLIGHT	Metalaxyl-M 3.3% + Chlorothalonil 33.1% SC	300-400 ml/acre

FAQs related to Leaf Blight in Maize

Q. What causes leaf blight in maize?

A. Leaf blight in maize caused by fungi (Exserohilum turcicum, Setosphaeria turcica) thrives in warm, moist conditions, impacting crop health and yield.

Q. How can I identify leaf blight in maize?

A. Leaf blight is a fungal disease that affects corn plants, causing dark spots on leaves and reducing crop yield.

Q. Which fungicide is recommended for Leaf Blight in Maize?

A. Fungicides like copper oxychloride, tebuconazole, Metalaxyl, and chlorothalonil can help control leaf blight. Follow application instructions for best results.