Fall Armyworm has many naturally-occurring 'natural enemies', which can be known as the 'farmers' friends'. These biological control agents are local predator and parasite insects that opportunistically feed or parasitize FAW. In the homeland of FAW in the Americas, and probably in Africa, these natural enemies can be active during all development phases of FAW, i.e. in the egg, larval, pupal and adult stage. Other natural enemies include various species of entomopathogenic fungi, polyhedrosis viruses and enotompathogenic nematodes. Epizootic outbreaks of fungal and viral diseases have been recorded in FAW, but such outbreaks are rare and only occur under optimal humidity conditions. However, natural enemies certainly have the potential to substantially reduce the FAW populations and hence the damage caused by FAW. Their impact however depends on a number of factors including the diversity of organisms being active, their life-style, local presence, numerical and timely abundance, host specificity, agronomic practices, pest management methods, etc.
A major challenge is to create conditions on the farm to exploit the potential of these beneficial natural enemies to their full extend. Broad-spectrum pesticides usually kill most of the farmers' friends, so it is important that the use of pesticides is reduced as much as possible and the farmer should leave certain areas of natural habitat (ecotone areas) unsprayed that can become a refugia site for these beneficial organisms. It is important that farmers recognize the pest in all its development stages, its associated natural antagonists, identity possible gaps to be filled in local natural enemy guilds and to manage their crops and surrounding lands in support of an IPM strategy as much as possible.
Biological control is an integral component of IPM and an important part of mutually compatible pest-suppressing methods aimed at generating higher profits, whilst preserving the environment and human health.
Biological control agents (BCAs) include the following:
predatory
insects and mites, which eat their prey.
In this category you find natural enemies that kill one or several
individuals of FAW during their life time either as larvae or adults. These
include Earwigs
(Dermaptera: Forficulidae, Carcinophoridae), Ladybird beetles (Coleoptera: Coccinellidae), Ground beetles (Coleoptera: Carabidae), Assassin and flower bugs (Hemiptera: Reduviidae,
Pentatomidae, Geocoridae, Nabidae, Anthocoridae), Eusocial, solitary and other
predatory wasps (Hymenoptera: Vespoidea), Ants (Hymenoptera: Formicidae), Spiders
(Arachnida: Araneae) and birds and bats;
Parasitoids, which
are insects with a free living adult stage and a larval stage that is parasitic
on another insect. The majority of
parasitoids known to be associated with the FAW are the tiny Brachonid and
Chalcid wasps, and less frequently flies (tachinids); and
Parasites and microbial pathogens, such as nematodes, fungi, bacteria, viruses and protozoa, which cause lethal infections. Pathogens (microorganisms that can cause disease) are everywhere. In agriculture, plant pathogens affect plants, reducing yield or quality. Also very important, but less perceived by farmers, are entomopathogens – those fungal, viral and bacterial pathogens that affect insects ('entomo-').
Fall Armyworm is naturally affected by several different types of pathogens. These are well reported in its home range in the Americas, but there are increasing reports of pathogen outbreaks impacting FAW in Africa.:
Viruses, in particular Nuclear Polyhedrosis Virus (NPVs), such as the Spodoptera Frugiperda Multicapsid Nucleopolyhedrovirus (SfMNPV)
Fungi, in particular
Metarhizium anisopliae, Metarhizium rileyi and Beauveria bassiana
