N. S. Azad Thakur - Academia.edu (original) (raw)

Papers by N. S. Azad Thakur

Pest Management in Horticultural Ecosystems, 1997

Ecological studies on Pieris brassicae (L.) revealed that there were four generations with two o... more Ecological studies on Pieris brassicae (L.) revealed that there were four generations with two overlapping generations in low and mid altitude conditions and 2-3 generations at high altitude hills. Thus, there were 6—9 generations in a year. The winter generations had longer life cycle than the generations recorded during summer and rainy seasons. Higher temperature directly inﬂuenced different stages (R2=O.99). The temperature range of 152°C-30°C was found ideal for the pest multiplication during May-June. However, the other abiotic parameters did not inﬂuence the life cycle.

Agricultural science digest, 2007

Investigations were conducted to evaluate the effectiveness of two nematophagous fungi, Arthrobot... more Investigations were conducted to evaluate the effectiveness of two nematophagous fungi, Arthrobotrys oligospora and Paecilomyces lilacinus against root-knot nematode (Meloidogyne incognita) infecting okra. A. oligospora alone and in combination with P. lilacinus suppressed root galling and nematode population to a significant level, thereby improving plant growth parameters. P. lilacinus, alone failed to reduce root galling. There were no significant difference in time of applications.

Journal of entomology and zoology studies, 2020

North-Eastern hills region of India is very rich in fertile soil, biodiversity and conducive agro... more North-Eastern hills region of India is very rich in fertile soil, biodiversity and conducive agro-climatic conditions that make them ideal for the production of horticultural crops. The present investigation was carried out to study the biodiversity of insects in apple in mid hills of Meghalaya during the year, 2018. Based on taxonomic classification, the insect species were placed into 7 different orders viz. Coleoptera (17), Hemiptera (11), Lepidoptera (6), Diptera (4), Hymenoptera (3), Dermeptera (1) and Orthoptera (1). Major insect pests recorded were Green apple aphid, Pale tussock moth, Tussock caterpillar, Giant looper and Cocoa tussock caterpillar and remaining 21 species as minor insect pests. Natural enemies observed were Parasitic braconid wasp, pupal parasitoid, Tachnid fly, Syrphid fly (maggots), Assassin bug, Earwig and four different species of Coccinellid beetles. Honey bees and Hoverfly visited as pollinators on few apple flowering plants. Also five insect species v...

Meghalaya state is a part of North Eastern Himalayas and it is a land-locked territory with a geo... more Meghalaya state is a part of North Eastern Himalayas and it is a land-locked territory with a geographical area of 22 429 km, lying between 25° 47' and 26° 10' N latitude, and 89° 45' and 92° 47' E longitude. It is exceptionally rich in biodiversity of insect pests and their natural enemies (Firake et al. 2012a; 2012b), the Khasi and Jaintia hill districts of the state are one of the richest botanical habitats of Asia. The region is inhabited by three main tribal groups, the Khasi (42%), the Jaintia (12%) and the Garo (32%), which together comprise 86% of the state’s total population of 2.3 million. Besides, frequent dynamics in food grain production, climate of the region is highly conducive for the occurrence and multiplication of several insect pests. These insect pests cause enormous damage to the crops resulting into shortage of food production in the region. Stored grain pests of worldwide importance including rodents also cause huge losses. The state is rich i...

Rodent outbreaks are believed to be associated with bamboo flowering (mautam) throughout the Worl... more Rodent outbreaks are believed to be associated with bamboo flowering (mautam) throughout the World. The ‘Mautam’ is the most important bamboo flowering event periodically observed at an interval of 48 (± 2) years in Mizoram, North East India. Past reports revealed heavy food grain losses during such events due to rodent outbreaks, which are believed to increase in numbers because of feeding on bamboo seeds. In several cases, 100% yield losses were found, leading to many deaths and migration of people. Because of rare occurrence and little studied event, mass flowering in bamboo gave rise to lots of myths and rumors all over the world and especially in tribal areas like Mizoram (India). Several enigmas are known from the state during Mautam; likewise one surprising fact about rodents and bats are common in Mizoram during flowering events. In this report, we tried to describe all these facts supported by all the available documents. A brief review is presented here. This is yet unsolv...

The field experiment was conducted to evaluate the bioefficacy of imidacloprid and thiacloprid ag... more The field experiment was conducted to evaluate the bioefficacy of imidacloprid and thiacloprid against chilli aphid (Aphis gossypii) during post kharif season of 2017at ICAR Research Complex for North Eastern Hill Region, Umiam, Meghalaya, India. The experiment was laid out in randomized block design (RBD) with seven treatments and three replications. Chilli (cultivar: Guntur Hope) seedlings (35 days old) were transplanted in 3mX4 m area with a spacing of 60 cm (R-R) × 40 cm (P-P). Total treatments viz. imidacloprid 17.8% SL (25 and 50 g a.i./ha), thiacloprid 21.7% SC (54 and 108 g a.i./ha) and dimethoate 30% EC (300 and 600 g a.i./ha) were applied twice at fifteen days intervals along with untreated control. The bioefficacy study revealed that the overall mean reduction of chilli aphid population was highest in imidacloprid at 50 g a.i. ha-1 with 80.33% reduction followed by thiacloprid (79.84%). The maximum fruit yield was also recorded in imidacloprid @ 50 g a.i./ha with 28.80 q/ha.

Current Science, 2013

North East (NE) India, commonly known as the 'land of seven sisters', is a territory of d... more North East (NE) India, commonly known as the 'land of seven sisters', is a territory of diverse ethnic groups, tribes and culture. Shifting cultivation, locally known as 'jhum' or 'jhumming', is a way of life for many of these tribes since time immemorial. The percentage utilization of cultivable area in this region (62.04) is less than the national average (73.05).

Indian journal of nematology, 2007

Indian Journal of Entomology, 2021

Seasonal incidence of major insect pests of apple in mid hills of Meghalaya was evaluated during ... more Seasonal incidence of major insect pests of apple in mid hills of Meghalaya was evaluated during 2018 at the Experimental farm of CPGSAS, Umiam, Meghalaya. A total of 43 insect species were observed. The major ones include-green apple aphid Aphis pomi De Geer, pale tussock moth Calliteara pudibunda L., tussock moth Euproctis guttata Collenette, giant looper Ascotis selenaria Denis and Schiffermuller and cocoa tussock moth Orgyia postica Walker. Also, 21 species were observed as minor pests, ten species as natural enemies, two species as pollinators and five species as occasional visitors. Results revealed that the aphid incidence is at its peak (34.75 aphids/ 10cm apical length of twig/shoot/plant) on the 25 th SMW (standard meteorological week) (3rd week of June 2018). Such a peak of pale tussock moth larval incidence (3.82 larva/ plant) was during 28 th SMW (2 nd week of July). Likewise, the tussock moth larval incidence (4.15 larvae/ plant) was its peak on the 35 th SMW (last week of August). The giant looper was at its peak (3.46 larvae/ plant) in the 28 th SMW (2nd week of July). The cocoa tussock moth incidence was at the maximum of 4.75 larvae/ plant on the 26 th SMW (27 th June). Correlation coefficients (r) indicated significant correlation between the incidence of green apple aphid with maximum temperature; and larval incidence of tussock moth and cocoa tussock moth exhibiting a significant correlation with minimum temperature. Regression analysis done herein will provide the impact of independent variables on the dependent variables.

International Journal of Current Microbiology and Applied Sciences, 2018

During survey, cowpea [Vigna anguiculata (L) Walp.] was found severely affected by ascochyta blig... more During survey, cowpea [Vigna anguiculata (L) Walp.] was found severely affected by ascochyta blight and disease was found well distributed in the surveyed areas of Meghalaya. The per cent disease incidence was found maximum in Mawlai (52.34%) under East Khasi Hills followed by RRTC (45.57%) under Ri-Bhoi district. In average, PDI was found highest in Ri-Bhoi district (37.50%) and least in West Khasi Hills district (15.47%). Ascochyta phaseolorum was consistently isolated from symptomatic leaves. Plant extracts and fungicides were evaluated in vitro against the growth of the pathogen.Among the fungicides, propiconazole and carbendazim at 0.1 and mancozeb at 0.2 per cent concentrations gave 100% inhibition of mycelial growth. Among the plant extracts, garlic extract at 5% showed the highest per cent inhibition (86.91±1.07%) of mycelial growth followed by turkey berry at 15% (82.33±0.44%). These could be further evaluated under in vivo condition to confirm its efficacy and could be included as components for integrated disease management for ascochyta blight.

International Journal of Bio-resource and Stress Management, 2016

The field experiments were conducted at ICAR Research Complex for North Eastern Hill Region, Umia... more The field experiments were conducted at ICAR Research Complex for North Eastern Hill Region, Umiam, Meghalaya, India during 2011-2012 to evaluate some biopesticides and newly introduced insecticides against shoot and fruit borer of brinjal. The experiments were laid out in Randomized Block Design (RBD) with three replications. The treatments viz., azadirachtin 1 EC (2 ml l-1), karanjin 2 EC (2 ml l-1), anonin 1 EC (2 ml l-1), Bacillus thuringiensis (Bt.) (2 g l-1), emamectin benzoate 5 SG (0.4 ml l-1), flubendiamide 480 SC (0.3 ml l-1), chlorantraniliprole 18.5 SC (0.4 ml l-1), chlorpyriphos 20 EC (2 ml l-1) were applied thrice at fifteen days interval starting from initiation of shoot and fruit borer infestation. Results showed that chlorantraniliprole (2.46%) was the best treatment in reducing the shoot infestation (81.88% reduction) which was statistically at par with flubendiamide (3.08%) and emamectin benzoate (3.76%) with 77.37% and 71.95% reduction over untreated control, respectively. The overall mean fruit infestation were also minimum in chlorantraniliprole (5.76%) and flubendiamide (5.93%) treated plots with 79.45% and 78.84% reduction over untreated control plots (28.03%), respectively. Pooled data of two years experimental results indicated that highest marketable yield was recorded in chlorantraniliprole treated plots (155.01 q ha-1) followed by flubendiamide (149.50 q ha-1), emamectin benzoate (134.24 q ha-1) and chlorpyriphos (125.43 q ha-1). Among bio-pesticides, highest mean marketable yield was recorded in Bacillus thuringiensis treated plots (114.45 q ha-1) followed by azadirachtin (101.11 q ha-1).

Journal of Entomology and Zoology Studies, 2019

A study was conducted to determine the effect of artificial diets on some of the important biolog... more A study was conducted to determine the effect of artificial diets on some of the important biological parameter of Helicoverpa armigera under laboratory condition at 25±1°C, 75±5% R.H. and 14 hr photoperiod. Four locally available pulses viz., chickpea, green gram, pea and black gram were used as treatments and compared with that of the natural diet as control i.e. chickpea leaves. Sixty larvae in each treatment were fed and studied. Results revealed that larval duration was found to be the minimum in larvae reared on chickpea based diet and longer on pea, green gram and black gram respectively and maximum on chickpea leaves. Overall, the fitness index was found highest on chickpea followed by pea, green gram, black gram, black gram and chickpea leaves. The study proved that chickpea based diet was the best for mass rearing of Helicoverpa armigera while pea based diet could also be used as substitute.

Mitochondrial DNA Part A, 2017

Abstract The Northeastern region of India, one of the mega biodiversity hot spots has enormous po... more Abstract The Northeastern region of India, one of the mega biodiversity hot spots has enormous potential for the production of fruits and vegetables. Fruit flies of the genus Bactrocera Macquart are important pests of fruits and vegetables, and one of the limiting factors in successful production of these commodities. The relationship among some of the species is unclear due to their high molecular and morphological similarities. Moreover, due to the significant morphological resemblance between fruit fly species, reliable identification is very difficult task. We genetically characterized 10 fruit fly species of the genus Bactrocera by using standard DNA barcoding region of COI gene. The characterization and identification of eight species were straight forward. This study was unable to establish the molecular identity of Bactrocera sp. 2. Within the 547 bp region of partial COI gene, there were 157 variable sites of which 110 sites were parsimony informative, 153 were synonymous substitutions and 4 were non-synonymous substitutions. The estimate of genetic divergence among the ten species was in the range of 0–21.9% and the pairwise genetic distance of Bactrocera. (Bactrocera) dorsalis (Hendel) with B. (B.) carambolae was only 0.7%. Phylogenetic analysis formed separate clades for fruit and vegetable infesting fruit flies. B. (B.) aethriobasis Hardy, B. (B.) thailandica and B. (B.) tuberculata (Bezzi) have been reported for the first time from the Northeastern India. The information generated from this study would certainly have implications for pest management, taxonomy, quarantine and trade.

The ecological aspects of rodents during bamboo flowering (BF) phase (Mautam) were studied in Meg... more The ecological aspects of rodents during bamboo flowering (BF) phase (Mautam) were studied in Meghalaya and Mizoram states of India during 2005-2008. Rodent population was almost stable during BF in Meghalaya. Likewise, it was also normal in Mizoram during 2005 to 2007. However, rodent outbreak was observed after gregarious flowering (GF) of M. baccifera during 2007-08 in Mizoram and it was more severe after complete fruit shedding. Rodent activities were found to be highest during July to October and their population was significantly higher in upland cultivated areas especially near animal farm-houses. Out of 12 species recorded, merely six species of rodents were observed in BF areas of Mizoram. Surprisingly, Bandicota bengalensis was recorded to be a pre-dominant species, though not observed in bamboo forests. Species wise, sex ratio of rodents varied from 1:0.81 to 1:1.12 in Mizoram. Furthermore, rodent population was recorded to be higher in GF areas and location wise it was more in Kolasib district of Mizoram. In general, sex ratio of rodents was quite equal in all districts of Mizoram; however it was basically female biased in sporadic flowering (SF) areas. Maturity status of rodents in Mizoram indicated their complete adulthood during flowering time; where testes and vaginas were largely scrotal and perforated type, respectively. Overall study concludes that, bamboo flowering alone didn’t increase rodent population significantly; but other factors mainly weather and starting time of flowering could also be involved in this complex process.

Journal of Genetics, 2015

Florida Entomologist, 2013

BioOne Complete (complete.BioOne.org) is a full-text database of 200 subscribed and open-access t... more BioOne Complete (complete.BioOne.org) is a full-text database of 200 subscribed and open-access titles in the biological, ecological, and environmental sciences published by nonprofit societies, associations, museums, institutions, and presses.

Guava is one of the most refereed and legendary fruit because of its hardy and positive bearing n... more Guava is one of the most refereed and legendary fruit because of its hardy and positive bearing nature, high vitamin C content and more income with minimum inputs (Singh 2010). In India, guava is cultivated on 204.8 thousand hectares of land and production is about 2462.3 million tons (Anonymous 2011). Large number of insect pests has been reported to occur on guava at various growth stages, but a few are a real menace to the cultivation of this crop. More than 80 species of insects and mites have been recorded on guava trees affecting the growth and yield. Major pest of guava in the NEH region includes trunk borer, Aristobia testudo (Coleoptra: Cerambycidae). A. testudo is the most destructive pest of Litchi in China and severe incidence of this beetle was first observed in Meghalaya on guava during 1997. Recently, the same pest was also found on pigeon-pea at the adult stage. About three species of fruit fly, Bactrocera dorsalis, B. cucurbutae and B. tau (Diptera, Tephritidae) fou...

The Coleopterists Bulletin, 2013

Guava, Psidium guajava (L.) (Myrtaceae), is the fourth most intensely cultivated tree fruit on th... more Guava, Psidium guajava (L.) (Myrtaceae), is the fourth most intensely cultivated tree fruit on the Indian subcontinent (Chandy 2002). Guava is exceptionally hardy, and even on marginal lands it bears marketable fruit with high vitamin C content and maintains for its producers an attractive income versus investment profile (Singh 2010). In India, guava is cultivated on about 205,000 hectares which yield about 2,500 metric tons per annum (Anonymous 2011). The subtropical climatic conditions of the northeastern Indian state of Meghalaya generate a single, relatively well defined guava fruiting and harvest cycle. During April and May, guava produces its flowers and then fruits in September to October. A large number of insect pests have been reported to occur on guava, but only a few of those reported are known to constitute a significant impediment to the successful cultivation of this crop (Shylesha et al. 2000; Firake et al. 2013). Recently, adult specimens of the elephant beetle genus Xylotrupes Hope were found feeding on the flesh of guava fruits in Meghalaya (Fig. 1), causing considerable losses in yield (35–45%). Furthermore, the often minimal damage inflicted by these beetles on the mature fruits can predispose the fruits to secondary attack by other insects (Fig. 2) and pathogens, all of which can augment market losses. On occasion, up to 98% of fruit can be damaged by Xylotrupes. Three male specimens of Xylotrupes from Meghalaya were sequenced at the 5′ region of the COI gene (NCBI Accession No: KF494189) and these sequences were found by Jen-Pan Huang, University of Michigan (personal communication) to nest within an unpublished, large series of specimens sequenced at the same region of COI gene. The latter series was assembled from diverse localities across Southeast Asia and had been previously identified as Xylotrupes siamensis Minck by criteria in Rowland (2003, 2011). According to the latter evidence, the identity of the Xylotrupes beetles found attacking guava in Meghalaya is here assigned as X. siamensis. Xylotrupes siamensis is reddish brown to black in color and 30–40 mm in body length. The males bear cephalic and pronotal horns, and the females are smaller and do not bear horns (Endrödi 1985; Waite and Elder 2000). The genus Xylotrupes is one of the most widespread genera of large beetles in the world. Its natural distribution extends over nearly a third of the earth’s circumference from the high valleys of Himalayan Pakistan east and south into India, Southeast Asia, China, the Malay Archipelago, Australasia into Melanesia as far as Vanuatu in the South Pacific (CAB International 2002; Rowland 2003, 2011, in Foreword in Hwang 2011). Xylotrupes beetles are known to be polyphagous, feeding on bark, fruits, panicles, and inflorescences of a large number of host plants viz., Acacia mearnsii De Wild (Fabaceae), Toona australis Kuntz (Meliaceae), pineapple, longan, lychee (Waite and Elder 2000), bamboo, coconut, cashewnut, cinnamon, African oil palm, rubber, banana, plantain, sugarcane, potato (CAB International 2002), passion fruit (Shylesha and Rao 2004), maize, sword bean (Shylesha et al. 2006), okra (Nair et al. 2001), poinciana, gulmohar, cacao, and som (Eswarareddy and Rajan 2011). To our knowledge, infestation or management of Xylotrupes beetles on guava has not been previously reported. For this reason, we have initiated studies based upon quantifiable variables associated with feeding by X. siamensis on guava fruit in the orchards of our experimental farm in Meghalaya, so that feasible

Use of rat traps is an ecologically sound and cheaper method of rodent management. Bamboo floweri... more Use of rat traps is an ecologically sound and cheaper method of rodent management. Bamboo flowering and subsequent rodent outbreaks are common in North East India; hence tribal communities of the region have invented their own local devices to control rodents. Attempts were therefore made to collect the information on different indigenous traps and bait stations and also to evaluate their effectiveness at different locations in Mizoram. Four indigenous rodent traps and some bamboo made bait stations were commonly observed in the region. Amongst, traps, Vaithang and Chepthang were found to be highly efficient over conventional traps. Similarly, bamboo made bait stations were also observed to be more effective than other methods. Although, conventional traps were found less efficient but they can further be modified as per the design of efficient indigenous traps and could be commercialized for effective rodent management.