Frequently Asked Questions
1) What is the fall army worm?
The fall army worm is the larval life stage of a fall army worm moth. Its scientific name is frugiperda which means (Lost fruit in Latin) because of its ability to destroy crops, cause loss and low yields. It is a heavy feeder and remarkably also practices cannibalism.
In addition, the fall armyworm (Spodoptera frugiperda) gets its name from its feeding habits whereby they eat everything in an area until it is over. The entire army then moves to the next available food source.
2)How many eggs can the female moth lay in her lifetime?
The female fall army worm moth can lay up to 1000 – 2000 eggs in her lifetime. They reproduce at a rate of several generations per year.
3) How long does it take for the life cycle of fall army worm to be completed?
During summer it takes 30 days, 60days during spring and autumn, while it takes 80-90 days during winter.
4) What is the life cycle of the fall army worm?
Stage 1 – Egg
The egg is normally dome-shaped and measures around 0.4mm by 0.3mm. The female fall army worm prefers to lay the eggs under the leaves, but when the eggs are many they are laid just anywhere. Thus, it is essential to look everywhere for the eggs for early detection before infestation and spread. They normally hatch into larvae within a short time when it’s warm than during other seasons.
Stage 2 – Larvae
The larva goes through six different instars that vary in pattern and physical appearance. This stage mainly lasts for 14-30 days depending on the temperature. It is normally about 1.5-2.0 inches in length with a distinctive inverted Y suture on the forehead. During this stage is when the fall army worm is the most destructive.
Stage 3 – Pupa
The larva then pupates underground for 7 to 37 days in a cocoon in the form of soil and silk. The temperature of the environment is what determines the pupae stage.
Stage 4 – Adult Fall Army worm
After the emergence the adults live for about 10 days and sometimes up to 21 days. The female mostly lay most of their eggs early in life
5) How to differentiate a fall army worm from other army worms?
In order to differentiate one needs to look at the head of the insect. The fall army worm’s head has a predominantly white inverted Y-shaped suture between the eyes. The young larvae are greenish or brownish with a smooth skin.
The mature larvae vary from green or light tan to nearly black. They also possess three yellow white hairlines down their backs next to a wider dark stripe. They also have a wingspan of 32 to 40mm with dark grey mottled (colored spots) on the forewings with light and dark splotches marks. There is also a noticeable white spot near the extreme end of the worm.
6) What crops are mainly destroyed by the fall army worm?
The species of crops mainly affected are; maize, rice, wheat, sorghum, millet, sugarcane, vegetable crops, cotton, potatoes, and avocado.
7) How does the fall army worm spread?
The fall army worm moth can spread really fast and fly up to 100km in one night with the assistance of the wind.
8) How does fall army worm destroy the plants?
In the larval form, the fall army worms normally burrow into crops, destroy and eventually kill the plants. Moreover, they can feed on more than 80 plant species.
9) Which animals are natural enemies of fall army worms?
They are ants, earwigs, small wasps, swollen dead caterpillars and mummified fungi.
10) Which prevention measures can be used
- It is advisable for the farmer to avoid late planting and plant on time.
- There should be plant diversity by intercropping the crops
- Regular checking of the crops weekly helps to detect the pests early and control their spread.
- Be observant to note fall army worms egg masses and caterpillars
11) Actions to take
There are various measures you can take to curb the spread of fall army worms and destroy them. These include:
- Spraying sugary water in the farm to attract and maintain a large population of ants, who are a natural enemy of the fall army worms.
- You can also collect caterpillars killed by fungus or virus, liquefy, strain and spray the liquid on the plants.
- Alternatively you can also apply ash, sand or soil to plants with damaged leaves. This tends to desiccate young larvae.
- Using chili powder or wood ash
- You can also use botanic pesticides such as neem
- You can also use bio_pesticides as recommended by extension officers/agrovets around
You should be careful about the insecticides and pesticides you use to ensure they don’t affect humans or the environment. Some are toxic and can cause health hazards.
12) Which are the application techniques used?
These include dose and formulation technique. When the fall army worms are down in the whorls, it is essential that the insecticides reach them there. Spraying using backpack sprayers may be ineffective if the delivering material doesn’t reach the whorl.
14) Are aerial applications of pesticides recommended fo Fall Army Worms?
The destructive larvae mainly dig deep into the whorl of maize occasionally thus, making aerial applications of the pesticide not that effective.
15) Organic products that can be used to control armyworms in the farm.
- Nimbecidine – which is a neem based biopesticide.
- Pyrethrum extract
- Chilli powder