Army Worm

About this pest

The Army Worm: Marching Menace in South African Fields

Armyworms, those relentless and destructive caterpillars, can quickly turn a farmer’s dream into a nightmare. In South Africa, two main armyworm species pose a significant threat:

1. African Armyworm (Spodoptera exempta):

• Common South African Names: Kommandowurm (Afrikaans), Nutgrass Armyworm
• Physical Characteristics: Green to black caterpillars with prominent white stripes and distinctive dark spots. Typically 4-5cm long when mature.
• Damage: Feeds heavily on grasses, especially maize, sorghum, and pasture, causing extensive defoliation and yield losses.

2. Fall Armyworm (Spodoptera frugiperda):

• Common South African Names: No specific South African name, mainly referred to as Fall Armyworm
• Physical Characteristics: Light brown to yellowish caterpillars with dark head capsules and inverted Y-shaped markings on the head. Up to 5cm long when mature.
• Damage: Feeds on a wider range of crops including maize, sorghum, soybeans, peanuts, and potatoes, causing significant economic damage.

Why are Army Worms a Pest?

• Massive outbreaks: They can form large marching groups, consuming everything in their path and quickly stripping fields bare.
• Rapid reproduction: Females lay hundreds of eggs, leading to exponential population growth and increased damage potential.
• Difficult to control: They can migrate long distances, making early detection and control challenging.

Combatting Army Worms:

• Early detection: Monitor fields regularly for egg masses, young caterpillars, and defoliation patterns.
• Natural methods: Encourage natural predators like birds, wasps, and parasitic nematodes.
• Biological insecticides: Bacillus thuringiensis (Bt) is a bacterium selectively targeting caterpillars, safe for other insects and humans.
• Chemical insecticides: Use specific insecticides registered for armyworm control, but consider environmental impact and resistance development.
• Cultural practices: Crop rotation, intercropping, and proper field sanitation can help reduce infestations.

Remember:

• Prompt action is crucial to managing Armyworm outbreaks effectively.
• Integrate multiple control methods for a sustainable approach.
• Seek professional advice from agricultural extension services or pest control specialists for specific recommendations.

By understanding the Armyworm and adopting proactive measures, South African farmers can protect their precious crops and livelihoods from these marching menaces.