science

Striga asiatica

Striga asiatica is a science 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 Striga asiatica rather than just read about it. In short: Striga asiatica, the Asiatic witchweed or the red witchweed, is a hemiparasitic plant in the family Orobanchaceae. It is native to Asia and sub-Saharan Africa, but has been introduced into other parts of the world including Australia and the United States.

Key takeaways

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

Reference excerpt

Striga asiatica, the Asiatic witchweed or the red witchweed, is a hemiparasitic plant in the family Orobanchaceae. It is native to Asia and sub-Saharan Africa, but has been introduced into other parts of the world including Australia and the United States. Asiatic witchweed is a serious agricultural pest, as it parasitises important crop species, including corn, rice, sorghum, and sugar cane, often causing substantial yield reductions. While it is native to Africa and Asia, it is invasive in farmlands of Kenya, Tanzania and Uganda. In the US, this witchweed was discovered in the Carolinas in 1956. It is considered an invasive agricultural pest, and a vigorous eradication campaign has reduced the affected area by 99% [from 450,000 acres (1,820 km2) to about 3,400 acres (1,400 ha)].

Biological control can be achieved by growing a Desmodium (tick-trefoil) undercrop (see push–pull technology). The trefoil can be used as green manure or animal fodder after the harvest.

Description S. asiatica seedlings are not visible above ground, but white succulent shoots can be found attached to host roots. Mature plants have green foliage above ground, sparsely covered with coarse, short, white, bulbous-based hairs. Mature plants are normally 15–30 centimetres (5.9–11.8 in) tall, but have grown to 60 centimetres (24 in). Leaves are nearly opposite, narrowly lanceolate, about 1–3 centimetres (0.39–1.18 in) long, with successive leaf pairs perpendicular to one another. Flowers, produced in summer and fall, are small (less than 1.5 centimetres (0.59 in) in diameter), sessile and axillary, with a two-lipped corolla, occurring on loose spikes. Flower colour varies regionally, from red, orange, or yellow in Africa to pink, white, yellow, or purple in Asia. The flowers give way to swollen seed pods, each containing thousands of dustlike seeds. Underground stems are white, round with scale-like leaves, turning blue when exposed to air. The roots are succulent, round, without root hairs, and found attached to a host species root system.

References

Sources Simberloff, Daniel. 2003. Eradication - preventing invasions at the outset. Weed Science 51:247–253. Striga asiatica in Brunken, U., Schmidt, M., Dressler, S., Janssen, T., Thombiano, A. & Zizka, G. 2008. West African plants - A Photo Guide. Forschungsinstitut Senckenberg, Frankfurt/Main.

External links Species Profile- Witchweed (Striga asiatica), National Invasive Species Information Center, United States National Agricultural Library. Lists general information and resources for Witchweed. "Red witchweed". Business Queensland. 2016-10-12. Retrieved 2021-09-28.

Illustrations

Worked examples

Example 1 — a first encounter with Striga asiatica

Start with the simplest possible case. Write down what Striga asiatica claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, 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 Striga asiatica 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 Striga asiatica 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 Striga asiatica

In research: Striga asiatica appears in science 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 Striga asiatica 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: Striga asiatica is common in secondary-school and first-year university syllabi. It links to neighbouring topics Botanical taxa named by Carl Linnaeus, Orobanchaceae, Parasitic plants, so understanding it makes those chapters shorter.
In everyday life: Look for Striga asiatica 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 Striga asiatica in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Striga asiatica 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 Striga asiatica out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Striga asiatica in simple terms?

Why does Striga asiatica matter?

Because it connects several science 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 Striga asiatica?

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 Striga asiatica.