CA-05/03/2026
Contents
1. Cassava brown streak disease (CBSD)
2. Musa sikkimensis
3. Cushing Syndrome
4. Karbi Anglong Ginger
5. Moniligaster girishi and drawida reynoldsi Earthworm
6. Ruddy Shelduck
Cassava brown streak disease (CBSD)
Why in News?
- A viral disease-causing root rot in cassava is raising alarms in sub-Saharan Africa as of March 2026, threatening millions reliant on the crop for food and income. Recently risks of spread to West Africa, including major producers like Nigeria and Ghana, urging stronger prevention.
About CBSD
- CBSD is caused by two viruses: Cassava Brown Streak Virus (CBSV) and Ugandan Cassava Brown Streak Virus (UCBSV), both in the Ipomovirus genus.
- Transmitted mainly by whitefly vector Bemisia tabaci in a semi-persistent manner; also spreads via infected cuttings used for planting.
- Leaves show feathery chlorotic veins, blotches, and mottling.
- Stems develop brown streaks or lesions, sometimes leading to die-back.
- Roots suffer necrosis and hard rots, often undetected until harvest, causing total crop loss.
- Yield losses up to 100% in susceptible varieties; roots become inedible.
- Affects East, Central, and Southern Africa; historically coastal Tanzania/Mozambique, now Uganda, Zambia, Rwanda, and beyond.
- Cassava is Africa's second-most important staple by calories, worsening food shortages.
- First noted over 70 years ago in coastal East Africa; recent inland expansion tied to high whitefly populations.
- Human-mediated via contaminated planting material; whiteflies drive field spread.
- Use resistant/tolerant varieties; ongoing breeding screens for resistance genes.
- Community phytosanitation (roguing infected plants) reduced incidence in studies.
- Clean cuttings, vector control, and monitoring essential; no cure once infected.
Why in News?
- Nagaland University researchers released a study titled "Exploring the Genetic Diversity of Musa sikkimensis Land Races in Nagaland, India," published in the journal Flora and Fauna. The research, led by Dr. Animesh Sarkar with co-authors KR Singh and Dr. S Walling, underscores urgent conservation needs amid deforestation threats to this endangered germplasm.
Key Characteristics
- Native to Eastern Himalayas (Sikkim, Darjeeling) and Northeast India (Nagaland); also called Darjeeling or Sikkim banana.
- Wild, seeded species not widely cultivated for edible fruit, but serves as a genetic reservoir for crop resilience.
- Shows strong adaptability to heat, cold, diseases, and environmental stresses, aiding development of resilient banana varieties.
Research Highlights
- Genetic diversity analysis reveals high potential for sustainable farming and long-term food security in biodiversity hotspots.
- Study maps local landraces, identifies wild populations, and creates a biodiversity corridor for conservation.
- Part of ongoing postgraduate/PhD projects at Nagaland University, praised by Vice-Chancellor Prof. Jagdish K. Patnaik.
Conservation Status
- Faces risks from forest loss and habitat threats in a global biodiversity hotspot.
- Urgent call to preserve germplasm for breeding climate-tolerant crops.
- Supports broader efforts in mapping banana diversity and evaluating genetic resources.
Why in News?
- Recent coverage (March 2026) links to new podcasts and articles distinguishing it from stress-related high cortisol, amid ongoing clinical trial updates.
About Cushing Syndrome
- Rare condition from excess cortisol (stress hormone) affecting body functions.
- Differs from Cushing's disease (specific pituitary tumor cause).
- Exogenous: Long-term corticosteroid use (e.g., for asthma, arthritis).
- Endogenous: Pituitary tumors (ACTH excess), adrenal tumors, or ectopic ACTH tumors.
- Less common: Adrenal carcinoma or nodular hyperplasia.
- Weight gain (central obesity, buffalo hump, moon face).
- Skin changes (thin skin, bruising, purple stretch marks).
- Muscle weakness, osteoporosis, high blood pressure, mood changes.
- In kids: Obesity, slow growth.
Treatment
- Surgery: Remove pituitary/adrenal tumors (first-line).
- Medications: Cortisol inhibitors (e.g., ketoconazole, relacorilant, pasireotide).
- Radiation or bilateral adrenalectomy for resistant cases.
Complications
- Infections, blood clots, diabetes, heart disease, fractures.
- Mental health issues (depression, anxiety).
Why in News?
- Assam achieved its first-ever export of GI-tagged Karbi Anglong Ginger, with a 21.2 metric tonne consignment flagged off from Guwahati to London on March 1-2, 2026.
Key Information
- Geographical Indication (GI): It received its GI tag in 2015, certifying its unique origin and quality attributes specific to the Karbi Anglong district of Assam.
- Distinctive Characteristics:
- Aroma & Pungency: Known for a bold, earthy flavour and high pungency.
- Oil Content: Contains a high essential oil content, making it highly desirable for industrial and culinary use.
- Fibre Content: Valued internationally for its desirable fibre content.
- Cultivation Methods:
- Mainly grown in the Singhasan Hills.
- Cultivated using traditional, age-old systems like Jhum (shifting) cultivation and Tila farming.
- Predominantly organic by default, as most farmers avoid synthetic chemicals and fertilizers.
- Varieties: The two most common types are Nadia (known for high yield and low fibre) and Aizol (highly pungent and aromatic).
- Medicinal Properties: Widely used in traditional medicine for its anti-inflammatory and digestive benefits.
- Economic Impact: The recent export push is part of a broader government strategy to boost farmers' income by linking them directly to high-value international supply chains.
Moniligaster girishi and drawida reynoldsi Earthworm
Why in News?
Common Habitat & Origin
- Location: Both species were found in the Nilgiri Biosphere Reserve of the Western Ghats.
- Biological Roots: They belong to a family believed to have evolved millions of years ago in the region of the Malay Archipelago or Myanmar.
- Endemism: The genus Moniligaster is specifically endemic to the Western Ghats.
Moniligaster girishi
- Discovery Site: Found in tropical wet evergreen forests near Chembotti, often tucked inside decaying logs.
- Naming: Named in honour of Dr. P. Girish Kumar, a scientist at the Zoological Survey of India.
- Distinctive Traits:
- Belongs to the gravelyi species-group.
- Features a unique undivided spermathecal atrial gland on each side of its anterior body.
- Possesses a smooth, tubular prostatic capsule that flattens into a strap-like shape.
Drawida reynoldsi
- Discovery Site: Collected from high-altitude montane grasslands between Sispara and Anginda.
- Naming: Named after John Warren Reynolds, a renowned Canadian earthworm expert.
- Distinctive Traits:
- Belongs to the robusta species-group, characterized by glandular prostates and bilobed atria.
- Identified by a distinct sausage-like prostatic capsule and a large, erect spermathecal atrium.
Ecological Importance
- Soil Health: Like other earthworms, they play a vital role in nutrient cycling and maintaining the soil structure of delicate tropical ecosystems.
- Biodiversity Indicators: Their discovery underscores the "hidden diversity" remaining in the Western Ghats, a global biodiversity hotspot.
Why in News?
Residents of Mudh village in eastern Ladakh have gained recognition for a 20-year tradition of protecting these birds during their breeding season, specifically by escorting fledglings safely to the Indus River.
About Ruddy Shelduck
- Large waterfowl (58–70 cm) with striking orange-brown (ruddy) plumage and a pale cream head.
- In flight, they display a sharp contrast between white wing-coverts and black flight feathers.
- Sexual Dimorphism: During breeding season, males develop a narrow black neck ring.
- Breeding: High-altitude wetlands in Central Asia, Tibet, Mongolia, and southeastern Europe. Ladakh is its only known breeding site in India.
- Wintering: Migrates south to the Indian subcontinent and parts of Southeast Asia from October to April.
- Known as one of the world's highest-flying ducks, capable of scaling the Himalayas at altitudes reaching 6,800 metres.
- An omnivore that feeds on grasses, young plant shoots, grains, aquatic plants, and small invertebrates.
- Revered in Buddhism as sacred and a symbol of marital fidelity.
- Commonly referred to in Indian folklore and local languages as Chakwa (male) and Chakwi (female).
Conservation Status:
- Listed as Least Concern on the IUCN Red List due to its wide range and large population.
- Protected under Schedule IV of the Wildlife Protection Act in India.
Question & Answer
Question 1. Consider the following statements about the 'Ruddy Shelduck':
1. It is a migratory bird that scales the Himalayas at altitudes reaching over 6,000 metres.
2. In India, Ladakh is its only known breeding site.
3. It is listed as 'Critically Endangered' in the IUCN Red List.
Select your answer:
A) 1 and 2 only
B) 2 only
C) 1 and 3 only
D) 1, 2 and 3
Explanation: (A)
Statements 1 and 2 are correct. The Ruddy Shelduck is known for its high-altitude flight (up to 6,800m) and Ladakh is the only confirmed breeding ground for this species within India. Statement 3 is incorrect because the Ruddy Shelduck is categorized as 'Least Concern' on the IUCN Red List due to its large global population and wide distribution range.
Question 2. In the context of Indian biodiversity, 'Musa sikkimensis', recently studied by researchers in Nagaland, is best described as:
Select your answer:
A) A critically endangered medicinal plant endemic to the Silent Valley.
B) A wild, seeded banana species that serves as a genetic reservoir for climate resilience.
C) An invasive succulent species threatening the alpine meadows of the Himalayas.
D) A new variety of dwarf wheat developed for organic farming in the North-East.
Explanation: (B)
Option (b) is correct. Musa sikkimensis, also known as the Darjeeling or Sikkim banana, is a wild species native to the Eastern Himalayas. While its fruits are seeded and not typically eaten, the plant is highly valued for its genetic diversity and adaptability to environmental stresses, making it a vital resource for breeding climate-resilient banana varieties.
Question 3. Consider the following pairs regarding recently discovered earthworm species:
1. Moniligaster girishi — Found in tropical wet evergreen forests.
2. Drawida reynoldsi — Found in high-altitude montane grasslands.
3. Silent Valley National Park — Located in the Nilgiri Biosphere Reserve.
Select your answer:
A) 1 and 2 only
B) 2 and 3 only
C) 1 and 3 only
D) 1, 2 and 3
Explanation: (D)
All pairs are correctly matched. Moniligaster girishi was discovered in the evergreen forests of Silent Valley (specifically near Chembotti). Drawida reynoldsi was found in the high-altitude grasslands (sholas) between Sispara and Anginda. Silent Valley National Park is a core part of the Nilgiri Biosphere Reserve in the Western Ghats.
Question 4. The 'Karbi Anglong Ginger', which recently saw its first-ever export consignment to London, is characterized by which of the following?
Select your answer:
A) It is grown primarily in the fertile alluvial plains of the Brahmaputra valley.
B) It is traditionally cultivated using Jhum (shifting) and Tila farming systems.
C) The 'Nadia' variety of this ginger is known for its exceptionally high fibre content.
D) It received its Geographical Indication (GI) tag in the year 2023.
Explanation: (B)
Option (b) is correct. Karbi Anglong Ginger is grown in the hilly terrain of the Karbi Anglong district (specifically Singhasan Hills) using traditional Jhum and Tila farming. Option (a) is incorrect as it is a hill-grown variety. Option (c) is incorrect because the Nadia variety is actually known for having low fibre. Option (d) is incorrect as it received the GI tag in 2015.
Question 5. With reference to 'Cushing Syndrome', which of the following statements is correct?
Select your answer:
A) It is a metabolic disorder caused by the body's inability to process glucose due to insulin resistance.
B) It results from the chronic overproduction or external intake of the hormone cortisol.
C) It is a condition exclusively caused by malignant tumors in the thyroid gland.
D) The syndrome is primarily treated through long-term administration of corticosteroid medications.
Explanation: (B)
Option (b) is correct. Cushing Syndrome occurs when the body is exposed to high levels of the hormone cortisol for a long time. This can be 'endogenous' (caused by pituitary or adrenal tumors) or 'exogenous' (long-term use of corticosteroid medications). Option (d) is incorrect because long-term use of corticosteroids is actually a cause of the syndrome, not the treatment.
Question 6. With reference to 'Cassava Brown Streak Disease' (CBSD), which has recently raised concerns regarding food security in Africa, consider the following statements:
1. It is caused by viruses belonging to the Ipomovirus genus.
2. The disease is primarily transmitted by the whitefly vector Bemisia tabaci.
3. Unlike other viral diseases, the root necrosis caused by CBSD is easily visible in the early stages of crop growth.
Select your answer:
A) 1 and 2 only
B) 2 and 3 only
C) 1 only
D) 1, 2 and 3
Explanation: (A)
Statements 1 and 2 are correct. CBSD is caused by Cassava Brown Streak Virus (CBSV) and Ugandan Cassava Brown Streak Virus (UCBSV), both in the Ipomovirus genus. It is transmitted by the whitefly Bemisia tabaci and through infected cuttings. Statement 3 is incorrect because root necrosis and hard rots often remain undetected until harvest, which is why it is particularly devastating as farmers only realize the crop loss at the final stage.
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