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The Hindu
23-07-2025
- Science
- The Hindu
A beetle-fungi combo threatens plantations in rubber capital Kerala
Rubber plantations in Kerala have been under threat since a beetle-fungus alliance has been attacking trees, causing severe leaf fall and rapid drying. Researchers at the Kerala Forest Research Institute in Thrissur recently identified the parasite to be the ambrosia beetle (Euplatypus parallelus). In their new study, published in Current Science, the beetle has been reported to share a mutualistic relationship with two fungal species, Fusarium ambrosia and Fusarium solani. This is the first report of F. solani in association with the adult ambrosia beetles. Fungi in the galleries Earlier, farmers working in the rubber plantations in the Irrity-Kannur region of Kerala noticed latex oozing from the barks of rubber trees. Under the Tree Health Helpline project, they alerted researchers from the Institute, insect ecologist Jithu Unni Krishnan said. Ambrosia beetles get their name from the ambrosia fungi that call the beetle their home. The name 'ambrosia' is not taxonomic but ecological. These beetles are native to Central and South America. They were first reported in India in the cashew trees of Ponda, Goa, in 2012. These beetles attack dead or infected trees, although they're also known to attack stressed trees. At times, the stressed trees release ethanol, a volatile compound that the ambrosia beetles can sense and attack. The beetles don't feed on the woody bark of trees; the fungi do. The beetles bore tunnels called galleries in the bark, carry fungi into the galleries, and farm the fungi to concentrate nutrients. The beetles and their larvae feed on nutrient-rich fungal mycelia. The fungi also release enzymes that weaken the wood, allowing beetles to penetrate deeper. In other insect hosts, the fungi are present in sacs called mycangia. In the present study, however, the team didn't find mycangia in the ambrosia beetle. Krishnan said that it's of interest to study how the fungal species interact with each other while coexisting in a beetle without the mycangia. Long time to heal The beetle-fungus association harms trees in many ways. Aside from weakening the structure, the duo causes severe leaf fall, trunk drying, and in some cases even tree death. The infection also affects total latex production from rubber trees, causing economic and agricultural losses. To combat the infection, experts follow specific methods, such as using antifungal agents, removing the infected part of trees, burning or chipping away any part that displays holes, and preventive measures such as using traps for ambrosia beetles. Further, once a tree is infected, it takes a long time to heal. 'The systemic infections progress through the plant xylem, blocking the xylem vessels. Moreover, proliferation of the fungus inside the xylem leads to sporulation, which leads [it] to secrete several enzymes, weakening the wood strength and showing death in distinct parts of the tree,' Amey Redkar, reader at the National Centre for Biological Sciences, Bengaluru, an independent expert working on Fusarium oxysporum, also a plant pathogen, said. Controlling a fungal infection in plants is difficult. The fungi reside in deeper parts of an infected plant, where insecticides or fungicides often don't reach. 'Once [fungi] have progressed systemically, it's too late to save a plant from it. Many Fusarium sp. spread either through soil or can also be carried by insect vectors,' Redkar added. 'As these pathogens have adapted to outcompete neighboring microbes to reach their vascular niche, they have evolved to modulate the surrounding microbiome.' Future team-ups A few species of ambrosia beetles, including Euplatypus parallelus, are invasive and threaten horticulture and silviculture worldwide. Being flying insects, they can access a variety of trees. 'It can infest to my understanding more than 80 species of broadleaf trees, including cashew, teak, coconut, and coffee,' Krishnan said. While the beetle has coevolved with its fungal partners, it may in future associate with other pathogenic fungi, posing a bigger threat to plantations. Likewise, Fusaria sp. are very virulent and known to expand their host range. 'The concern is how many indigenous virulent pathogenic fungi are likely to associate with this insect and thereby broaden the host range and impact of this insect,' Krishnan said. Fusarium fungi infect beetles as well as other organisms, including spiders, frogs, and humans. These fungiare opportunistic pathogens in humans, meaning they can affect those with a compromised immunity, posing a significant health risk to workers in rubber plantations, as well as other plants and animals within an ecosystem. Much to lose The destructive power of the beetle-fungi association and the risk of other pathogenic fungi teaming up with the beetles together portend alarm. According to experts, the possibility calls for an action plan to mitigate and prevent further attacks. Since the number of invasive ambrosia species is increasing as well, Krishnan said policymakers and researchers should step up, collaborate, and provide solutions to manage infections. India is the world's sixth-largest producer of rubber and the second-highest in terms of productivity. Kerala produces 90% and accounts for 72% of India's rubber cultivation area. While there are reports of successful phytosanitary measures in coniferous trees, the same measures may not work on broad-leaf trees such as rubber and teak. The infection also makes other economically significant plants, such as coffee, cashew, mango, and coconut, vulnerable to infections. To prepare, experts recommend management strategies be designed based on the geographic location of the plantations. 'Things that are applicable to other parts of the world may not be applicable to Kerala or South India,' Krishnan said. Redkar added that sustainable treatments, such as using antagonistic fungi that can compete with the pathogenic onesor using microbial consortia with a diversity of bacterial species that can live inside plants, can offer promising results in mitigating fungal infections in plants. Rohini Karandikar is a science communicator, educator and facilitator. She currently works at TNQ Foundation as a consultant.
Indian Express
01-06-2025
- Science
- Indian Express
Very few have courage to stand up against astrology today: Mashelkar on Narlikar
SCIENTIST DR Raghunath Mashelkar recalled how astrophysicist Jayant Narlikar had the 'courage to stand up against pseudosciences like astrology', while noting that 'many could not do the same today'. Speaking virtually at a tribute event at the Pune International Centre on Saturday, Mashelkar said, 'He fought pseudoscience with reason, not with ridicule. And he stood up. I remember that I was in Delhi at that period of time, there was an effort to introduce astrology courses. And he was the first one to stand up and say astrology is not science. He had the courage to do that. We have very few people today who have the courage to do that. I don't want to elaborate on that.' In 2008, Narlikar teamed up with the late rationalist Narendra Dabholkar to conduct an experiment testing the validity of astrology. Published in scientific journal Current Science volume 96 in March 2009 titled 'A statistical test of astrology', the experiment invited astrologers to predict the mental capabilities of a set of 40 students based on their birth charts or kundalis. This set of 40 would be randomly drawn from a total set of 200 students. Half of these students were 'intellectually bright' in their schools while the other half were not. Out of all the astrologers who participated in the experiment, the best performance was 24 out of 40 correct answers while the average correct answer per sample was 17.5. These numbers were below the minimum threshold for success statistically calculated to be 28 correct answers. Mashelkar added that Narlikar invited pride in ancient Indian astronomy, showing how our scientific heritage is both rich and relevant. Narlikar's death on May 20 led to an outpour of tributes from scientists, citizens, and politicians from across the country. One of the most popular and accomplished scientists from India, Narlikar was the founding director of Inter-University Centre for Astronomy and Astrophysics. Soham is a Correspondent with the Indian Express in Pune. A journalism graduate, he was a fact-checker before joining the Express. Soham currently covers education and is also interested in civic issues, health, human rights, and politics. ... Read More
Hindustan Times
03-05-2025
- Science
- Hindustan Times
Climate crisis exposes flaws in Indus pact as some rivers may dry up quicker
The Indus river basin, among the most vulnerable regions globally to climate change, is experiencing dramatically different impacts across its eastern and western tributaries, recent scientific research has shown, potentially making previous agreements on sharing of waters between India and Pakistan irrelevant. Approximately 50-60% of the Indus basin's annual water discharge comes from snow and glacial melt, with recent research revealing stark differences in how climate change affects various parts of the basin. Recent papers have now found that western tributaries like the Indus, Kabul, Jhelum and Chenab are fed by glaciers with more stored water, while eastern tributaries including the Beas, Ravi, and Sutlej draw from significantly lower glacier stored water reserves. Crucially, the pace of glacial melt is higher in the Western Himalayas that feed eastern rivers compared to the Upper Indus basin. This east-west disparity challenges the fundamental assumptions of the 1960 Indus Waters Treaty, which allocated rivers based on historically stable flow patterns. 'From an entirely scientific perspective, the water sharing practices need to be revisited in view of climate change that can alter flow and increase disasters downstream,' said Anil Kulkarni, distinguished visiting scientist and glaciologist from Indian Institute of Science (IISc). The issue has gained renewed significance after India put the Indus Waters Treaty in abeyance following a terrorist attack in Kashmir on April 22. Under the treaty, India exclusively uses water from the eastern rivers (Ravi, Beas and Sutlej), while Pakistan has rights to the western rivers (Indus, Jhelum and Chenab), which hold 80% of the basin's water. A 2023 study titled 'Differential loss of glacier stored water in the Indus River basin', published in Current Science by researchers from the Birla Institute of Technology and Science, Indian Institute of Science, and Indian Space Research Organisation, used a combination of models to assess glacier stored water and mass loss. Their research found significant spatial variability in stored water and mass loss across the basin. 'Except for the upper Indus basin, all other sub-basins show a substantial rate of glacier mass loss, which can affect future water availability,' the paper concluded, suggesting the need to reconsider water-sharing practices. The upper Indus basin, allocated to Pakistan under the treaty, lies mainly in the Karakoram region, which exhibits the 'Karakoram anomaly' -- a surprising stability of glaciers despite the global trend of retreat. 'Latest projections indicate that glacial melt may begin in the upper Indus basin only in the 2050s. But other rivers and catchments will see far greater and faster glacial loss before then,' explained Kulkarni. 'The understanding is that water flow and hence availability will increase for the rest of the rivers (except Indus) now and then fall drastically around mid-century following extensive loss of glaciers.' A 2019 science policy brief by IISc's Divecha Centre for Climate Change predicted that due to high negative glacier mass balance and area loss, discharge for the eastern rivers (India's allocation) is expected to peak early in 2030, compared to 2070 for the western basin. According to research by the Kathmandu-based International Centre for Integrated Mountain Development (ICIMOD), glacial mass balance rates vary significantly: Western Himalayan glaciers at -0.36 meter water equivalent per year since 2010, Karakoram at -0.09, and Eastern Himalayas at -0.51. These changes carry serious implications for the basin's more than 300 million residents, who already face increased uncertainty due to rising temperatures, extended dry periods, floods, unseasonal rain, and glacial lake outburst floods (GLOFs). Water demand is also expected to rise as climate impacts become more pronounced, further straining resources. 'So far, there have been about 150 GLOF events recorded in Pakistan and 60 in India - mostly after the 1950s,' said Sher Muhammad, remote sensing Specialist at ICIMOD. 'The recorded fatalities in India due to these GLOFs are over6,000, compared to 11in Pakistan.' Pakistan experienced devastating floods in 2022 following extreme summer heat, resulting in 1,100 deaths and affecting 33 million people. The Indus basin spans 1.1 million square kilometres across four countries: 52% in Pakistan, 33% in India, 8% in China, and 6% in Afghanistan. From 1991 to 2015, the mean temperature across the Western Himalaya and Karakoram regions rose by 0.65°C, according to monitoring by the Indian Institute of Science. Future projections suggest that even if global warming is limited to 1.5°C, warming in the Hindu Kush Himalaya will be higher, with a 4–25% increase in monsoon rainfall expected long-term. Himanshu Thakkar of South Asia Network on Dams, Rivers and People emphasised that 'contribution from glaciers and snow to western rivers is higher compared to eastern rivers. Monsoonal flow also contributes to eastern rivers. Apart from conflict and geopolitics, these rivers are a source of life to people.'
