biology

Metarhizium acridum

Metarhizium acridum is a biology topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Metarhizium acridum rather than just read about it. In short: Metarhizium acridum is the new name given to a group of fungal isolates that are known to be virulent and specific to the Acrididea (grasshoppers). Previously, this species has had variety status in Metarhizium anisopliae (var. acridum); before that, reference had been made to M. flavoviride or Metarhizium sp. describing an "apparently homologous and distinctive group" of isolates that were most virulent against Sch…

Key takeaways

Metarhizium acridum belongs to biology; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Metarhizium acridum to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Metarhizium acridum from memory before moving on to harder problems.

Reference excerpt

Metarhizium acridum is the new name given to a group of fungal isolates that are known to be virulent and specific to the Acrididea (grasshoppers). Previously, this species has had variety status in Metarhizium anisopliae (var. acridum); before that, reference had been made to M. flavoviride or Metarhizium sp. describing an "apparently homologous and distinctive group" of isolates that were most virulent against Schistocerca gregaria (desert locust) in early screening bioassays.

Biology M. acridum almost exclusively infects grasshoppers (order Orthoptera): researchers believe that this has to do with the Mest1 gene which is not present in M. acridum. By taking a strain of M. robertsii that has a nonfunctioning Mest1 gene, researchers found that the mutant was only able to infect Melanoplus femurrubrum, which is consistent with M. acridum activity. This allows the initiation of the infection process on the specific targets. The expression of Mest1 in the entomopathogen M. acridum is triggered by substances that are only found on the waxy coat of the grasshoppers, which explains why this pathogen specifically only targets grasshoppers and locusts.

Applications

Biological Insecticide M. acridum has been used to control locusts and other grasshopper pest species: originally by the international LUBILOSA programme (which developed the product Green Muscle). This team identified and addressed key technical challenges for exploitation of microbial control agents, including isolate selection, mass production, and delivery systems (formulation and application). Insect control (mortality) depends on factors such as the number of spores applied against the insect host, the formulation and weather conditions. Oil-based formulations allow the application of fungal spores under dry conditions, and are compatible with existing ultra-low volume (ULV) application techniques for locust control. As of 2012, M. acridum was under consideration by the USDA for release in the Western U.S. for control of native grasshoppers and crickets.

Important isolates IMI 330189 (= ARSEF 7486) is the ex-type of the species, originally collected from Niger: the active ingredient of 'Green Muscle'. CSIRO FI 985 (= ARSEF 324) is an Australian isolate: the active ingredient of 'Green Guard'. EVCH077 is the active ingredient of 'NOVACRID'.

Gallery

References

See also Zhang, L; Lecoq, M. (2021). Nosema locustae (Protozoa, Microsporidia), a biological agent for locust and grasshopper control. Agronomy 11, 711. DOI:10.3390/agronomy11040711

Illustrations

Worked examples

Example 1 — a first encounter with Metarhizium acridum

Start with the simplest possible case. Write down what Metarhizium acridum claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In biology, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Metarhizium acridum before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Metarhizium acridum ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Metarhizium acridum

In research: Metarhizium acridum appears in biology research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Metarhizium acridum in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Metarhizium acridum is common in secondary-school and first-year university syllabi. It links to neighbouring topics Biopesticides, Clavicipitaceae, Fungi described in 2009, so understanding it makes those chapters shorter.
In everyday life: Look for Metarhizium acridum outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Metarhizium acridum in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Metarhizium acridum means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Metarhizium acridum out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Metarhizium acridum in simple terms?

Why does Metarhizium acridum matter?

Because it connects several biology ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Metarhizium acridum?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Metarhizium acridum.