Integrating Mulberry Nematode Ecology and Soil Health in NEP 2020 Towards safeguarding the silk heritage of Manipur
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Loukrakpam Bina Chanu and N Mohilal Meitei
Among the most elusive yet impact-ful organisms are nema- todes, microscopic roundworms that silently infiltrate plant roots, often going unnoticed until the damage is done. These tiny invaders are more than just a nuisance. Root-parasitic nematodes pierce plant roots, disrupt nutrient uptake and leave crops vulnerable to disease and drought. Their presence can lead to: Stunted growth and yellowing leaves, Reduced crop yields and economic losses and Imbalanced soil ecosystems. While some nematodes play a vital role in decomposing organic matter and controlling pests, the parasitic varieties pose a serious threat to global agriculture. Their stealthy nature makes early detection difficult, and their resilience challenges even the most advanced pest control strategies.
Mulberry (Morus spp.), the primary food source for silkworms, is vulnerable to several plant-parasitic nematodes that compromise root health and productivity. Some of the most important plant parasitic nematodes of concerned to mulberry plants are - 1. Root-Knot Nematodes (Meloidogyne spp.) which is the dominant species in mulberry fields. The nematode induce root galling, stunted growth, chlorosis and reduced leaf yield. These disrupts water and nutrient uptake, leading to poor cocoon quality and silk production. 2. Reniform Nematodes (Rotylenchulus spp.) which are found in warmer mulberry-growing regions, reduceds root mass, causes leaf yellowing, and poor plant vigor are the main symptoms that affects nutrient absorption and overall plant health. 3. Lesion Nematodes (Praty- lenchus spp.) which are migratory endoparasites that invade root tissues, induce necrotic lesions on roots, leading to secondary infections. These weakens root systems and increases susceptibility to other patho- gens. 4. Spiral Nematodes (Helicotylenchus spp.) which are often found in mixed populations with other nematodes, induce mild root damage, but can exacerbate stress under poor soil conditions. Thus, weakens root systems and increases susceptibility to other pathogens. 4. Spiral Nematodes (Helicoty-lenchus spp.) which are often found in mixed populations with other nematodes, cause mild root damage, but can exacerbate stress under poor soil conditions.
Nematodes are classified into functional groups based on their feeding habits and ecological roles: Bacte-rivores-Feed on soil bacteria. They promote nutrient mineralization and microbial turnover. Fungivores-onsume fungal hyphae. They help regulate fungal populations and support decomposition. Herbi- vores (Plant-Parasitic)-attack plant roots (e.g., Meloidogyne, Pratylen-chus). They cause root galls, lesions, and reduce nutrient uptake. Omnivores- that feed on multiple sources including microbes and small invertebrates. They are adaptable and resilient in changing environ- ments. Predators-prey on other nematodes or micro-fauna. They help control pest populations and maintain soil balance.
In a study conducted across selected mulberry-growing sites in the valley districts of Manipur, including Mulberry farm, Kalika village, Irilbung, Imphal East; Regional Tasar Research Station, Chingmeirong, Imphal West; Khangabok Wangbal Government Silk Farm, Wangbal, Thoubal District and Sericulture Training Station, Kwata, Bishnupur District during 2005 - 2012. Soil samples are collected during both pre-monsoon and post-monsoon seasons to capture seasonal variation. Soil samples are collected from the rhizosphere zone (0–30 cm depth) of mulberry plants using a sterilized auger. Each composite sample consists of 5–10 subsamples taken randomly around the root zone of a single plant. Approximately 500 g of soil per site is collected, labelled, and transported in sterile polythene bags. Fine feeder roots are carefully excavated from the same plants during soil sampling. Roots are washed gently under running water to remove adhering soil particles.
Modified Cobb’s Sieving and Decanting Technique followed by Baermann Funnel Method are used to extract nematodes from soil samples. Extracted nematodes are collected after 24–48 hours and preserved in 4% formalin. Roots are chopped into 1–2 cm segments and processed using the Modified Baermann Technique. Nematodes are collected from the root exudates after 48 hours.
Nematodes are killed by gentle heat and mounted on temporary slides using glycerin. Morphological identi- fication are carried out under a compound microscope using standard taxonomic keys (e.g., Siddiqi, 2000; Mai & Mullin, 1996). Key diagnostic features such as stylet structure, esophageal glands, tail shape, and vulva position are used for identification. Photomicrography is employed to document representative species. Frequency, abundance, and density of each species are calculated using standard ecological indices. Data are analysed using ANOVA to determine significant differences in nematode popu- lations across districts and seasons. Diversity indices such as Shannon -Wiener and Simpson’s Index are calculated to assess nematode community structure. Correlation analysis has been performed to relate nematode abundance with soil parameters (pH, organic matter, moisture).
Mulberry farms in Imphal Valley are significantly affected by a diverse range of soil and plant parasitic nematodes, as revealed by detailed research conducted in the valley districts of Manipur.
These nematodes pose a serious threat to mulberry health and, consequently, to silk production The study identifies a rich diversity of nematode species, with particular empha- sis on those belonging to the family Hoplolaimidae, which are known for their aggressive parasitic behaviour. Key nematode genera found in the Imphal Valley mulberry soils include;
(To be contd)
Among the most elusive yet impact-ful organisms are nema- todes, microscopic roundworms that silently infiltrate plant roots, often going unnoticed until the damage is done. These tiny invaders are more than just a nuisance. Root-parasitic nematodes pierce plant roots, disrupt nutrient uptake and leave crops vulnerable to disease and drought. Their presence can lead to: Stunted growth and yellowing leaves, Reduced crop yields and economic losses and Imbalanced soil ecosystems. While some nematodes play a vital role in decomposing organic matter and controlling pests, the parasitic varieties pose a serious threat to global agriculture. Their stealthy nature makes early detection difficult, and their resilience challenges even the most advanced pest control strategies.
Mulberry (Morus spp.), the primary food source for silkworms, is vulnerable to several plant-parasitic nematodes that compromise root health and productivity. Some of the most important plant parasitic nematodes of concerned to mulberry plants are - 1. Root-Knot Nematodes (Meloidogyne spp.) which is the dominant species in mulberry fields. The nematode induce root galling, stunted growth, chlorosis and reduced leaf yield. These disrupts water and nutrient uptake, leading to poor cocoon quality and silk production. 2. Reniform Nematodes (Rotylenchulus spp.) which are found in warmer mulberry-growing regions, reduceds root mass, causes leaf yellowing, and poor plant vigor are the main symptoms that affects nutrient absorption and overall plant health. 3. Lesion Nematodes (Praty- lenchus spp.) which are migratory endoparasites that invade root tissues, induce necrotic lesions on roots, leading to secondary infections. These weakens root systems and increases susceptibility to other patho- gens. 4. Spiral Nematodes (Helicotylenchus spp.) which are often found in mixed populations with other nematodes, induce mild root damage, but can exacerbate stress under poor soil conditions. Thus, weakens root systems and increases susceptibility to other pathogens. 4. Spiral Nematodes (Helicoty-lenchus spp.) which are often found in mixed populations with other nematodes, cause mild root damage, but can exacerbate stress under poor soil conditions.
Nematodes are classified into functional groups based on their feeding habits and ecological roles: Bacte-rivores-Feed on soil bacteria. They promote nutrient mineralization and microbial turnover. Fungivores-onsume fungal hyphae. They help regulate fungal populations and support decomposition. Herbi- vores (Plant-Parasitic)-attack plant roots (e.g., Meloidogyne, Pratylen-chus). They cause root galls, lesions, and reduce nutrient uptake. Omnivores- that feed on multiple sources including microbes and small invertebrates. They are adaptable and resilient in changing environ- ments. Predators-prey on other nematodes or micro-fauna. They help control pest populations and maintain soil balance.
In a study conducted across selected mulberry-growing sites in the valley districts of Manipur, including Mulberry farm, Kalika village, Irilbung, Imphal East; Regional Tasar Research Station, Chingmeirong, Imphal West; Khangabok Wangbal Government Silk Farm, Wangbal, Thoubal District and Sericulture Training Station, Kwata, Bishnupur District during 2005 - 2012. Soil samples are collected during both pre-monsoon and post-monsoon seasons to capture seasonal variation. Soil samples are collected from the rhizosphere zone (0–30 cm depth) of mulberry plants using a sterilized auger. Each composite sample consists of 5–10 subsamples taken randomly around the root zone of a single plant. Approximately 500 g of soil per site is collected, labelled, and transported in sterile polythene bags. Fine feeder roots are carefully excavated from the same plants during soil sampling. Roots are washed gently under running water to remove adhering soil particles.
Modified Cobb’s Sieving and Decanting Technique followed by Baermann Funnel Method are used to extract nematodes from soil samples. Extracted nematodes are collected after 24–48 hours and preserved in 4% formalin. Roots are chopped into 1–2 cm segments and processed using the Modified Baermann Technique. Nematodes are collected from the root exudates after 48 hours.
Nematodes are killed by gentle heat and mounted on temporary slides using glycerin. Morphological identi- fication are carried out under a compound microscope using standard taxonomic keys (e.g., Siddiqi, 2000; Mai & Mullin, 1996). Key diagnostic features such as stylet structure, esophageal glands, tail shape, and vulva position are used for identification. Photomicrography is employed to document representative species. Frequency, abundance, and density of each species are calculated using standard ecological indices. Data are analysed using ANOVA to determine significant differences in nematode popu- lations across districts and seasons. Diversity indices such as Shannon -Wiener and Simpson’s Index are calculated to assess nematode community structure. Correlation analysis has been performed to relate nematode abundance with soil parameters (pH, organic matter, moisture).
Mulberry farms in Imphal Valley are significantly affected by a diverse range of soil and plant parasitic nematodes, as revealed by detailed research conducted in the valley districts of Manipur.
These nematodes pose a serious threat to mulberry health and, consequently, to silk production The study identifies a rich diversity of nematode species, with particular empha- sis on those belonging to the family Hoplolaimidae, which are known for their aggressive parasitic behaviour. Key nematode genera found in the Imphal Valley mulberry soils include;
(To be contd)