FREQUENTLY ASKED QUESTIONS
(Questions and answers provided by CBAF team members, and sourced from "The African Armyworm: Regional Armyworm Programme of Desert Locust Control Organisation for Eastern Africa", published by DLCO-EA)
Questions and Answers have been grouped according to a common theme. Select the theme to view the related questions:
-
-
-
-
-
-
NB: If you have a FAQ which is not indicated here, please email KieserM@arc.agric.za and she will endeavour to answer your question.
Q. Why are armyworm considered a pest?
A. The armyworm is the larvae (worm stage) of a night flying moth, which in large numbers causes severe damage to grasses and cereal crops.
Q. What damage is done to cereal crops and grasses?
A. The damage is restricted to the leaves, although when food is scarce, young stems may be eaten. Heavy infestations of armyworm result in a total loss of leaves, often leading to severe crop loss or necessitatin re-planting.
Q. When I see a lot of butterflies during the day, could this be a sign of armyworm outbreaks?
A. No, because the moths of the armyworm do not fly during the day. The only indication of an armyworm outbreak is the number of moths that are caught in the monitoring traps set up.
Q. Why don't armyworm feed on non-cereal plants?
A. Armyworm are "specific" feeders of plant of the cereal family.
Life Cycle and Identification
Q. Why do armyworm larvae disappear within a short time at the end of their feeding?
A. Once the larvae have reached their last instar stage and the soil is moist and soft, they burrow into the ground where theymoult into a pupa within a few days. If you dig in the soil near the plants that have been damaged by the worms, you will find pupae.
Q. What colour is the armyworm adult?
A. Dark grey to velvet black. (Click HERE to read more about the biology of the armyworm)
Q. How long is the life cycle?
A. The whole life cycle takes about one month under normal outbreak conditions. Click HERE to read about the life cycle of the African Armyworm.
Q. How many eggs does each moth lay?
A. One female can lay between 100 and 400 eggs in a mass, and she can lay one mass every night for several consecutive nights, until she has laid about 1,000 eggs.
Migration
Q. How do armyworm move from one place to another?
A. The moths are able to fly hundreds of kilometres downwind during the night, and this could last for several succesive nights. When the moths take oof, they may reach heights of several hundred metres above the ground, where they meet winds that will carry them off in a downwind direction, thus moths are 'dispersed' further by the winds.
Outbreak Dynamics
Q. When is an armyworm outbreak likely to occur?
A. Armyworm survive and breed in low densities during the dry season, with periodic rainfall showers. These populations can increase rapidly after the rains arrive at the end of the dry season.
Q. What size are outbreaks?
A. Densities of larvae can build up to 1,000 larvae per square metre, and these concentrations can cover an area from one hectare to several hundred square kilometres.
Q. Why are outbreaks associated with the rains?
A. Moths are concentrated by being brought together in the air by wind convergences associated with rains storms.
Q. What time of the year do armyworm cause problems?
A. Outbreaks have been recorded from November to June in Kenya, and December to May in Tanzania.
Forecasting. Monitoring, & reporting
Q. What steps should I follow if there is an armyworm outbreak in my village?
A. 1. Inform the neighbouring farmers through the village Headman
2. Inform the Extension Worker
3. Source chemical and sprayers from the stockist
4. Spray the affected area
Q. How do I go about spreading information to others after I have predicted an outbreak?
A. 1. Inform the village Headman so that the village runner can spread the news
2. Send a message via your church, mosque, and/or school.
Q. What level of education is required for someone to be trained as a Community Armyworm Forecaster?
A. As long as you can read, write, and be able to count (eg. number of moths, rainfall etc) you can be trained to become a Community Armyworm Forecaster.
Q. How can I prevent damage to my crops?
A. To avoid crop damage it is essential to find and control the larvae before they developinto the 'black' or fourth instar stage. Local moth traps may indicate whether large numbers of moths are present in the area. One week after large moth catches (or a rain storm) check for young larvae by looking carefully at the leaves of the crops for "windowing", or young green larvae hanging by threads below the leaves. Report this to your local village Headman immediately.
Q. Will the Government provide the insecticide during an outbreak?
A. Due to the large areas that may be infested during an outbreak, it is not feasibile for the Government to provide insecticide to all the affected areas. Farmers are advised to buy insecticides from nearby stockists to avoid crop losses.
Q. Can the spread of an outbreak be stopped?
A. Control of primary outbreaks (low density populations) is critical. By effectively controlling these outbreaks, it should be possible to prevent a large upsurge of armyworm.
Q. Can armyworm outbreaks be controlled by natural enemies?
A. Natural enemies (eg. insects and birds) may have a significant impact on small outbreaks. However during a large upsurge, these natural enemies are unlikely to control the spread of the outbreak. |
