How To Control Fall Armyworm in Maize

Hey there! Are you worried about fall armyworm infestation in your maize crop? This article will walk you through some fantastic methods to control these pesky insects. From the traditional cultural and mechanical processes to the advanced biological and chemical approaches – we’ve got it all covered. Discover the best integrated pest management strategies that can help safeguard your maize crop and ensure a bountiful harvest.

Introduction

One of the most damaging pests in agriculture is the fall armyworm (FAW), which prefers maize but feeds on more than 80 other plant species. It is native to the Americas, but since 2016, it has invaded and spread across Africa and Asia, causing significant crop losses and threatening food security. According to the Food and Agriculture Organization of the United Nations (FAO), FAW can cause up to USD 9.4 billion in annual yield losses in Africa alone.

Fall Armyworm in Maize. Image:

Symptoms and signs of Fall armyworm (FAW)

Maize plants can be attacked by FAW at any stage of growth, but the larvae (caterpillars) that feed on the leaves, stems, and cobs cause the most damage. The main symptoms and signs of FAW infestation on maize plants are:

• Leaf damage: FAW larvae create irregular holes or windows on the leaves, often starting from the edge and moving toward the midrib. The damage can range from small pinholes to large ragged areas, depending on the size and number of larvae.
• Frass: FAW larvae produce dark brown or black droppings (frass) that accumulate on the leaves, stems, or soil near the infested plants.
• Egg masses: FAW adults (moths) lay clusters of 100 to 200 eggs on the underside of the leaves, usually near the leaf tip or edge. Whitish or grayish hairs cover the eggs, giving them the appearance of cotton or mold.
• Larvae: FAW larvae vary in color from light green to brown or black, depending on their age and strain. They have four dark spots arranged in a square on the last segment of their body. They can be found feeding on the leaves, hiding in the leaf whorls, or boring into the stems or cobs.

Different methods are available for controlling FAW on maize, such as cultural, biological, mechanical, and chemical methods. Each method has advantages and disadvantages and needs help providing complete control. Therefore, using an integrated pest management (IPM) approach that combines different methods according to the local conditions and needs is important.

Cultural methods

These methods aim to prevent or reduce FAW infestation by modifying the crop environment or management. Some of the cultural techniques that you can use for FAW control on maize are:

• Planting early: Planting maize as early as possible in the season can help avoid peak periods of FAW activity and reduce the exposure of young plants to high levels of infestation.
• Using resistant or tolerant varieties: Some maize varieties have traits that make them less attractive or susceptible to FAW attacks, such as hairy leaves, tight husks, or high levels of natural defense chemicals. These varieties can reduce FAW damage and improve yield.
• Intercropping with legumes or other crops: Planting maize with other crops that repel or distract FAW, such as legumes (beans, cowpeas, etc.), cassava, sorghum, or millet, can reduce FAW infestation and increase crop diversity and soil fertility.
• Rotating crops: Changing the type of crop grown in a field from one season to another can disrupt the life cycle and population build-up of FAW and other pests. For example, rotating maize with non-host crops such as rice, wheat, or vegetables can reduce FAW pressure.
• Removing crop residues: Destroying or removing crop residues after harvest can eliminate potential sources of food and shelter for FAW and other pests. This can reduce the survival and reproduction of FAW adults and larvae in the field.

The advantages of cultural methods are that they are generally low-cost, environmentally friendly, and easy to implement by farmers. They can also improve crop health and productivity by enhancing soil quality, water conservation, and nutrient availability. However, the disadvantages of cultural methods are that they may need to provide more control under high levels of FAW infestation or favorable weather conditions. They may also require more labor, land, or seeds than conventional methods.

Biological methods

These methods use natural enemies (parasitoids, predators, and pathogens) or natural substances (pheromones, botanical pesticides, and biopesticides) to control FAW populations. Some of the biological methods that you can use for FAW control on maize are:

Using natural enemies:

Natural enemies are organisms that kill or reduce FAW reproduction by feeding on or infecting them with diseases. Some examples of natural enemies that you can use for FAW control are:

• • Parasitoids: These are insects that lay their eggs inside or outside FAW larvae or pupae. The eggs hatch into larvae that feed on their host until they kill it. Some examples of parasitoids that attack FAW are wasps (Trichogramma spp., Telenomus spp., Cotesia spp., etc.) and flies (Tachinidae family).
  • Predators: These animals feed on FAW eggs, larvae, pupae, or adults. Some examples of predators that prey on FAW are birds, bats, rodents, spiders, ants, beetles, and earwigs.
  • Pathogens: These microorganisms cause diseases in FAW and reduce their survival or reproduction. Some examples of pathogens that infect FAW are bacteria (Bacillus thuringiensis, Serratia marcescens, etc.), fungi (Metarhizium anisopliae, Beauveria bassiana, etc.), viruses (Spodoptera frugiperda multiple nucleopolyhedrovirus), and nematodes (Steinernema spp., Heterorhabditis spp., etc.).

Using pheromone traps:

Pheromones are chemicals that FAW adults use to communicate with each other and find mates. Pheromone traps contain synthetic pheromones that attract FAW males and capture them. You can use pheromone traps to monitor FAW activity, population density, and migration patterns. They can also be used to reduce FAW mating and reproduction by mass trapping or mating disruption techniques.

Using botanical pesticides:

Botanical pesticides are substances derived from plants that have insecticidal properties. Some botanical pesticides effective for FAW control include neem, pyrethrum, garlic, and chili pepper. Botanical pesticides can be applied as sprays, dusts, or extracts to repel or kill FAW larvae or adults.

Using biopesticides:

Biopesticides are substances derived from microorganisms or natural products that have insecticidal properties. Some examples of biopesticides that can be used for FAW control are Bacillus thuringiensis (Bt), spinosad, abamectin, and azadirachtin. Biopesticides can applied as sprays or granules to kill FAW larvae or adults.

The advantages of biological methods are that they are generally more selective, safer, and more sustainable than chemical methods. They can also enhance the biodiversity and resilience of the crop ecosystem by conserving or augmenting the natural enemies of FAW and other pests. However, the disadvantages of biological methods are that they may need to be more readily available, affordable, and effective in some areas or situations. They may also require more knowledge, skills, or equipment than chemical methods.

Mechanical methods

Mechanical methods are practices that physically remove or kill FAW larvae or adults manually or mechanically. Some of the automated methods that you can use for FAW control on maize are:

• Handpicking: Handpicking is the simplest and most common method of controlling FAW on small-scale farms. It involves inspecting the maize plants regularly and removing any FAW eggs, larvae, pupae, or adults by hand. One effective method of removing FAW is crushing or immersing them in soapy water. This can help prevent further damage caused by the pests and protect your plants.
• Crushing egg masses: Crushing egg masses is another simple and effective method of controlling FAW on small-scale farms. It involves inspecting the maize leaves regularly and crushing any egg masses found on them with fingers or a stick. This can prevent the hatching of hundreds of FAW larvae per egg mass.
• Using light traps: Light traps are a great way to capture nocturnal insects like FAW adults. They use artificial light to attract the insects and can be made using simple materials like a lantern, bucket, funnel, and wire mesh. Using light traps, you can monitor FAW activity and population density at night and even reduce their mating and reproduction through mass trapping techniques. Give it a try!
• Applying poison baits: These are mixtures of food attractants and toxic substances that lure and kill FAW larvae or adults. You can make poison baits from locally available materials such as maize flour, molasses, water, and insecticides. Poison baits can applied as granules or balls around the base of the maize plants or near the infested areas.

The advantages of mechanical methods are that they are generally low-cost, environmentally friendly, and easy to implement by farmers. They can also immediately control FAW infestation and reduce the need for insecticide applications. However, the disadvantages of mechanical methods are that they may need to provide more control under high levels of FAW infestation or large-scale farming systems. They may also require more labor, time, or equipment than chemical methods.

Chemical methods

These methods use synthetic or organic insecticides or insect growth regulators to control FAW infestation by killing or inhibiting the development of FAW larvae or adults. Some of the chemical methods that You can use for FAW control on maize are:

• Applying synthetic insecticides: Synthetic insecticides kill FAW larvae or adults by affecting their nervous system, metabolism, or growth. Synthetic insecticides that can be used to control FAW include pyrethroids such as lambda-cyhalothrin and deltamethrin, organophosphates like chlorpyrifos and malathion, carbamates including carbaryl and methomyl, and diamides such as chlorantraniliprole and flubendiamide.
• Applying organic insecticides: Organic insecticides kill FAW larvae or adults by affecting their nervous system, metabolism, or growth. They are used for FAW control and are derived from natural sources such as plants, animals, or minerals. Examples include spinosad, abamectin, azadirachtin, and rotenone.
• Applying insect growth regulators: Insect growth regulators are substances that inhibit the development or reproduction of FAW larvae or adults by interfering with their hormones or enzymes. Some insect growth regulators used for FAW control are diflubenzuron, lufenuron, and pyriproxyfen.

The advantages of chemical methods are that they are generally more available, affordable, and effective than other methods. They can also provide rapid and consistent control of FAW infestation and reduce crop losses and yield gaps. However, the disadvantages of chemical methods are that they may pose risks to human health and the environment by causing toxicity, resistance, or residues. They may also affect the natural enemies and beneficial insects of FAW and other pests.

Some examples of recommended insecticides and their doses for Fall Armyworm control on maize are:

Recommended insecticides

Using insecticides safely and responsibly is important to avoid harming yourself, others, or the environment. Some of the tips for using insecticides safely and responsibly are:

• Follow the label instructions carefully, and do not exceed the recommended dose or frequency of application.
• When handling or applying insecticides, wear protective gear such as gloves, masks, goggles, and boots.
• Alternate modes of action to prevent or delay the development of resistance in FAW populations.
• Avoid spraying during flowering or near water sources to protect pollinators and aquatic life.
• Dispose of empty containers and leftover insecticides properly, and do not reuse them for other purposes.

Conclusion

Controlling FAW on maize is a challenging task that requires a combination of different methods according to local conditions and needs. Cultural practices can help prevent or reduce FAW infestation by modifying the crop environment or management. Biological methods can help control FAW populations by using natural enemies or natural substances. Mechanical methods can help remove or kill FAW larvae or adults manually or mechanically. Chemical processes can help control FAW infestation by applying synthetic or organic insecticides or insect growth regulators.

The most effective way to control FAW on maize is to use an integrated pest management (IPM) approach that combines different methods in a coordinated and complementary manner. IPM can help reduce the reliance on insecticides and enhance the sustainability and resilience of the crop ecosystem. IPM can also help improve crop health and productivity by reducing crop losses and yield gaps.

We hope this article has provided helpful information and guidance on controlling fall Armyworm on maize. If you have any questions about FAW control on maize, please share them with us in the comments section below. 

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I am Gaushoul Agam

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ToAgriculture

I am an experienced Horticulture Officer in the Department of Agricultural Extension in Bangladesh. I am committed to improving agriculture and farming.

I created ToAgriculture to address global food safety concerns. These concerns are caused by a growing population, diminishing farmland, and the impact of climate change on agriculture. I assist readers in learning modern farming techniques.

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