fungal disease Desert locust

Fungal Infection (Entomophthorales)

Entomophthorales fungal infection is a disease caused by microscopic fungi belonging to the order Entomophthorales. These fungi naturally attack locusts and other insects. They are sometimes studied as a means of biological control against...

What is it?

Entomophthorales fungal infection is a disease caused by microscopic fungi belonging to the order Entomophthorales. These fungi naturally attack locusts and other insects. They are sometimes studied as a means of biological control against locust invasions, as an alternative to chemical insecticides.

The disease affects locusts at all stages of development, from the young locust (called nymph) to the adult. It spreads particularly well when air humidity is high, which limits its use in arid areas where the desert locust typically lives.

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Commonly observed signs

These signs are neither exhaustive nor specific. Only a veterinarian can establish a diagnosis.

Related signs — each one links to its page:

An infected locust becomes progressively less active and eats less. It loses its coordination and displays abnormal movements or tremors. At an advanced stage, the insect often climbs up onto a plant or support before dying, a typical behavior called "summit disease" that promotes the spread of fungal spores to other locusts below.

After death, the locust's body becomes rigid and remains attached to the support. The cuticle (the insect's outer covering) may become covered with a fine down or powder corresponding to fungal spores, which may be visible to the naked eye in some cases.

When to consult without delay

This list does not replace veterinary advice. It gathers situations that justify a prompt consultation.

Causes and risk factors

The disease is caused by fungi of the order Entomophthorales, particularly species such as Entomophaga grylli which specifically infect locusts and grasshoppers. The fungus enters the insect's body through the cuticle, develops inside by invading tissues and organs, and then causes the host's death.

High humidity and moderate temperatures favor spore germination and disease spread. High densities of locusts, typical of swarms, also increase transmission from one individual to another. Conversely, the hot and dry conditions characteristic of desert areas where the desert locust lives naturally limit fungal development.

Diagnosis and care

Diagnosis is the veterinarian's responsibility, based on clinical examination and laboratory tests. Care is decided case by case.

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Identification of this disease relies on observing locust carcasses showing characteristic signs: a stiffened posture held at height, legs gripping the substrate, and the presence of spores or fungal downy coating on the body. Laboratory confirmation through microscopic examination or specialized analysis allows precise identification of the fungal species involved. This diagnosis is chiefly of interest to entomologists and locust surveillance and control organizations.

Treatment

There is no curative treatment for an already infected locust. However, preparations based on entomopathogenic fungi are developed and used as biological control agents, applied to locust populations as part of locust management programmes.

Treatment depends on the cause and the animal's condition: it must be determined by a veterinarian. No self-medication.

Prevention

In nature, there is no true means of prevention since this is a naturally occurring pathogen. Within biological control programmes, formulations based on entomopathogenic fungi may be deliberately applied to locust populations to limit their spread, as a complement to or replacement for conventional insecticides.

Possible complications

In individual insects, infection is almost always fatal once symptoms become apparent. At the population level, an epizootic (an epidemic affecting animals) can significantly reduce swarm numbers, which is generally viewed as a beneficial effect in the context of controlling locust invasions.

When to see a veterinarian

Observation of numerous locust carcasses clinging to vegetation at height in a monitored area.

Presence of unusual downy coating or powder on dead locusts.

Suspicion of a natural epizootic in an area where locust control operations are planned, so as to adapt the strategy.

Need for precise identification as part of a surveillance or research programme.

Prognosis

The prognosis is poor for the individual insect once infection is established: death generally occurs within several days. At the population level, the impact depends greatly on climatic conditions; insufficient humidity limits spread and therefore the effectiveness of the disease as a natural regulatory factor.

Frequently asked questions

Can this disease affect other insects or humans?

The fungi Entomophthorales are specific to insects and pose no danger to humans, domestic animals, or livestock. Some species can affect other orthopterans such as grasshoppers.

Why do dead crickets remain clinging to high places?

It is a behavior induced by the fungus itself, called summit disease. By driving the insect to climb before dying, the fungus promotes the dispersal of its spores to the soil and surrounding grasshoppers, ensuring its spread.

Is this disease used to fight against desert locust invasions?

Yes, entomopathogenic fungi, some of which are related to Entomophthorales, are being studied and sometimes used as a biological alternative to chemical insecticides in locust control, particularly to reduce the environmental impact of treatments.

Why is this disease rare in the desert?

The development of the fungus requires relatively high humidity for its spores to germinate and infect the insect. The arid and hot zones frequented by the desert locust do not often meet these conditions, which naturally limits epizootics.

References

FAO — Organisation des Nations unies pour l'alimentation et l'agriculture

Content reviewed by the TunisieVet editorial team · Updated 31 August 2026

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AT A GLANCE

AgentFungus
SpeciesDesert locust
VaccineNo
Transmissible to humansNo

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This information is provided for educational purposes only and is not a substitute for a veterinary consultation. If you have any concerns about your animal's health, consult a veterinarian.

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