What are armyworms?
Army caterpillars are larvae in the stage of growth of butterflies (flying at night - moths) which attack plants and crops of various types and cause great losses to farmers. Invasive beetles (Spodoptera frugiperda) are native to the tropical regions of America (Argentina and the Caribbean).
They were discovered in Africa for the first time in 2016 and first appeared in the countries of Benin, Nigeria, Sao Tome and Principe, and Togo. (FAO)
Until January 30 of 2018, the invading soldiers had been discovered and reported in almost all the countries south of the Sahara Desert except in the countries of Djibouti, Eritrea and Lesotho. (FAO)
For the first time they were seen in Tanzania in 2017 in Nkasi district in Rukwa region. Until now, the invading soldiers have reached more than 15 regions of Tanzania.
There are two types of armyworms: Fall ArmyWorms which are technically called Spodoptera frugiperda. And the African Armyworm (African Armyworm) which is technically called Spodoptera exempta. All of these pests are destructive to plants and crops, except they differ in their nature, and some eating habits.
Army caterpillars attack more than 80 types of plants/crops. They prefer cereal plants such as corn, sorghum, sorghum, rice, barley, wheat and sugarcane and vegetable crops.
In this article, we will talk more about Fall ArmyWorm ( Spodoptera frugiperda ). Where you will learn how to identify them, their life cycle, their effects on crops and how to control them.
Life Cycle Of Invasive Army Caterpillars
The Viwavijeshi butterfly lays many eggs that hatch after 3-5 days, after the eggs are hatched a caterpillar (caterpillar) appears which lives for 14-28 days. From the caterpillar stage, larvae emerge where they last for 7-14 days. From the larval stage the full butterfly emerges and can live for an average of 14 days.
- A butterfly flies up to 100 km a day so it can fly 2000 km in its lifetime
- A female butterfly can lay up to 2000 eggs in her lifetime
- Larvae attack plants and live for 14-28 days
- A military butterfly can have 6-12 generations per season
How To Identify Army Caterpillars
Weapons can be identified by the following characteristics:-
- Eggs are laid in clusters of 100-300
- The eggs are hidden by a white cotton-like membrane
- The eggs are laid on the underside of the plant leaf
- The egg hatches after 3-5 days
- Their butterflies emerge and fly only at night
- The wings of the male butterfly are marked with white triangles in the lateral and central corners
- The wings of the female butterfly are all brown and mottled
- The caterpillar has a "Y" mark on its head
- The caterpillar has four square-shaped dots in the eighth pincer from the head
Symptoms Of Armyworm Attacks
Insect infestations are identified through the developmental stages of these insects. Following are the steps of attack:-
- First step: The whitefly eats one side of the leaf
- Step two and three: Puts holes in the leaves
- Stages four to six: instar makes a large leaf (??)
- Sometimes it pierces the pods of the corn, attacks the grain, can hide in the stalk of the corn and also attacks the front.
The effects of pesticides on plants
- It attacks the leaves and makes the plant unable to grow properly
- It attacks the stem and causes the plant to fall and die
- The use of pesticides to control them causes health effects to the consumer through plant products (Phytotoxicity)
- It attacks the anthers and causes poor pollination conditions
- It attacks the grain and causes a poor yield as well as reducing the quality of the harvest.
Economic effects of armyworms
The invasion of these insects causes serious economic damage to society and the nation as a whole, some of these effects are:
- Increases production costs by purchasing pesticides to control them
- It can attack the whole field and make the farmer replant
- Governments can spend large budgets on programs to control these nuisances
- It can cause hunger and ultimately poverty for farmers and perhaps the nation as a whole
- The use of pesticides to control these pests causes damage to the environment which leads to other costs to maintain the environment
Pesticides Registered in Tanzania and Proven to Kill Invasive Armyworms
Here are the pesticides that have been proven to kill these pests when used correctly:-
Abamectin, cypermethrin, lamda-cyhalothrin, chlorpyrifos 480g/l, emamectin beanzoate 50g/l, pirimiphos methyl and deltametrin, acetamiprid, chlorantraniliprole…
Na Methomyl (carbamate) 900g/kg, lufenuron (benzamide) 50g/l, flubendiamide (belt 480 sc), indoxacarb, methomyl, baccilus thuringiensis, meterihzium anisoplie, lennate, spinosad.
The Right Time to Use Pesticides for Armyworms
Pests can only be prevented if pesticides are used correctly and at the right time. When using pesticides consider the following:-
- Use a TPRI registered pesticide
- Apply the correct mixture of water and pesticides (read the label or ask your local extension officer)
- Control bed bugs early before they hide
- Avoid mixing more than one pesticide in one pump
- Use protective equipment when spraying
Advice: Visit your farm regularly to identify the presence or status of infestation and take appropriate action.
For this year; have you seen weapons in your field or anywhere else? Please tell us in the comments where you have seen the soldiers and when, if it is only for this year!