Browsing by Author "Rajkumar"
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Item Biosuppression of Coconut Pests with Entomopathogenic Nematodes(2018) Rajkumar; Suchithra, M.Item Climate change and pest outbreaks in Palms(2018) Suchithra, M.; RajkumarItem Development of rapid, efficient and cost effective screening technique for testing arecanut against Phytophthora meadii incitant of fruit rot disease(2024) Prathibha, P.S.; Nagaraja, N.R.; Rajesh, M.K.; Daliyamol; K. P. Thejasri; Rajkumar; Vinayaka Hegde; Uchoi AnokTo accelerate identification of disease resistant arecanut germplasm or hybrids against Phytoph- thora , it is very much imperative to develop bioassays which could differentiate resistant and susceptible cultivars efficiently. Here, a cost effective and rapid technique, called the “Detached Leaf Assay ”, was developed to identify resistant germplasm at the seedling stage itself. Zoospore production in highly virulent Phytophthora meadii (P19) was standardized by incubating under a 12 hours light and dark regime. Zoospore suspension was adjusted to 105 spores ml-1 in Petri plates. Subsequently, surface sterilized arecanut leaves were floated in zoospore suspension and incubated at temperature of 24 ± 1 °C. Disease symptoms, including water-soaked lesions, were recorded three days after inoculation. Infection lesion increased from 1 to 7.3 cm2 . The pathogen was re-isolated and confirmed with the original culture. The assay was successfully validated to screen arecanut accessions, wild types and hybrids against P. meadii . This technique is the first to be developed, and it is simple, cost-effective, and faster. It also provides consistent infection and could be effectively utilized to screen arecanut germplasm or hybrids against P. meadii in the seedling stage itself.Item Distribution of Root - Knot Nematode on Crossandra in Rayalaseema Region of Andhra Pradesh(2015-06) Rajkumar; Nagesh, M.; Raghavendra, A; Srinivasa ReddyItem Effect of Chlorpyrifos on Survival and Virulence of Native Entomopathogenic Nematode(2018) Rajkumar; Jagadeesh Patil; Kesavan Subhaharan; Sujithra, MItem Entomopathogenic Nematodes in Pest management(2018) Rajkumar; Joseph Rajkumar, A.Item Euwallacea perbrevis (Schedl, 1951) and associated novel fungal symbiont, Fusarium sp.: A potential cause of wilting in cocoa, Theobroma cacao in India(2024) Shivaji Hausrao Thube; R Thava Prakasa Pandian; Rajkumar; Merin Babu; Josephrajkumar, A.; Santhoshkumar P; B.J. Nirmal Kumara; Vinayaka Hegde; Balanagouda Patil; H. Rajashekara; T. Prabhulinga; Babasaheb B. F; Shailesh Gawande; Dipak Nagrale; M. Devindrappa; Rajesh, M.K.Cocoa is a commercially important beverage crop that faces new challenges in the context of climate change, which can alter pest and disease dynamics in cocoa plantations. In the Dakshina Kannada district of Karnataka, India, an abrupt increase in cocoa wilt was observed during the 2017–18 and 2018–19 seasons. Systematic examination of affected trees revealed consistent attacks of Euwallacea perbrevis (Schedl, 1951; Coleoptera: Curculionidae: Scolytinae). In-depth studies of the wilted trees revealed the association of the plant pathogenic fungus Fusarium sp. with Euwallacea perbrevis. The identity of the obtained pure culture from the insect and infected tree was confirmed as Fusarium sp. using amplification of ribosomal DNA, RNA polymerase II largest subunit (RPB1) and translation elongation factor 1 (Tef1) genes. Notably, this study reports a remarkable case of mutualistic association between ambrosia beetles and Fusarium sp., belonging to the Fusarium solani species complex (FSSC), rather than the Ambrosia Fusarium clade (AFC). This finding highlights the intriguing diversity of mutualistic relationships in nature and sheds new light on the complex interactions between organisms. The present study also investigated the impact of rainfall on the colonization and spread of the Euwallacea-Fusarium complex. The findings revealed that rainfall was identified as a predisposing factor for the incidence and spread of attacks. Additionally, the study conducted a comprehensive analysis of the modeling of Euwallacea-Fusarium complex spread over a specific period of time.Item Farmers' Participatory Demonstration On Arecanut Based Cropping System -A Success Story(2017) Jaganathan, D.; Nagaraja, N.R.; Jose, C.T.; Rajkumar; Ananda, K.S.; Thamban, C.Item Field Evaluation of the Entomopathogenic Nematodes (Epns) for Sustainable Management of White Grub, Leucopholis Coneophora Burm. in Coconut(2022) Rajkumar; Sujithra, M; SubaharankItem Genetic Diversity Studies and Screening for Fusarium Wilt (Fusarium udum Butler) Resistance in Wild Pigeonpea Accessions, Cajanus scarabaeoides (L.) Thouars(2016) Nagaraja, N.R.; Arun Kumar, M.B.; Manjunath Prasad, C.T.; Rajkumar; Parimal Sinha; Jaagrati JainItem Impact of entomopathogenic nematodes on rhinoceros beetle larvae, Oryctes rhinoceros (Coleoptera: Scarabaeidae)(2012-11) Jagadeesh Patil; Rajkumar; Kesavan SubaharanItem Karungile verutheeni puzhakkale niyanthrikkan mithra keedangal(2017) Rajkumar; Leena, S.; Irfana; Vinayaka HegdeItem MANAGEMENT OF ROOT GRUB IN ARECANUT WITH ENTOMOPATHOGENIC NEMATODES -A SUCCESS STORY(2018) Rajkumar; Jaganathan, D.; Shivaji Hausrao Thube; Nagaraja, N.R.; Vinayaka Hegde; Ravi BhatItem Management of Root-knot nematode Infestation in Coconut Cropping System(2021) Rajkumar; Surekha, R; Sujithra, M; Prathibha, V.H.Item Management of White grub (Leucopholis burmesterie) infesting Arecanut through Entomopathogenic Nematodes under field conditions(2019) Rajkumar; Jagadeesh Patil; Rashid Pervez; Kesavan SubhaharanItem Mass production of Entomophaga and entomopathogens invading coconut pests(2018) Suchithra, M.; RajkumarItem Molecular Identification of Entomopathogenic Nematode Isolate and its Virulence to White Grub, Leucopholis burmeisteri (Coleoptera: Scarabaeidae)(2016) Rajkumar; Rachana, K.E.; Rajesh, M.K.; sabana, A.A.; Nagaraja, N.R; Shahin, S.; Subaharan, K.Item Multi-gene phylogeny and phenotypic analyses revealed an association of different Colletotrichum species with inflorescence dieback and leaf spot of arecanut in India(2024) Prathibha, V.H.; Rajesh, M.K; Akshay Dinesh; Balanagouda Patil; Daliyamol; Nagaraja, N.R.; Rajkumar; Sabana, A.A.; K.P. Gangaraj; K.P. Thejasri; Sunil S. Gangurde; Vinayaka HegdeArecanut is one of the economically important plantation crops. Among the various diseases, inflorescence dieback and leaf spot/blight diseases caused by Colletotrichum spp. have re-emerged as major factors impeding arecanut production in India in the last few years. To understand the Colletotrichum species complex in the arecanut system, we have characterized Colletotrichum spp. associated with inflorescence dieback and leaf spot/ blight of arecanut based on a combination of phenotypic, multi-locus (ITS, ACT, CHS-1, GAPDH, HIS3 and TUB2) phylogeny and pathogenicity studies. A total of 26 Colletotrichum isolates were obtained from arecanut inflorescence dieback (13 isolates) and leaf spot/blight (13 isolates) infected tissues collected from disease-endemic regions of Karnataka, Kerala and Tripura states of India. The combined multi-locus sequence analyses and a critical examination of phenotypic characters revealed the association of Colletotrichum aoteaora as a dominant species with arecanut inflorescence dieback disease. On the other hand, two Colletotrichum species, viz., C. siamense and C. fructicola, were distinctly associated with leaf spot/blight disease. All the Colletotrichum isolates studied were pathogenic to arecanut. Significant variations in lesion size were observed among the different species with cross-infection ability on inflorescence and leaves. This study represents the first comprehensive study of Colletotrichum spp. associated with arecanut inflorescence dieback and leaf spot/blight diseases. In addition, the study is the first record of C. aoteaora, C. siamense, and C. fructicola associated with the arecanut crop in this country. It provides valuable information for implementing effective IDM strategies against these diseases in India.Item A novel technique to guard juvenile palms from rhinoceros beetle attack(2021) Sujithra, M; Rajkumar; Vinayaka Hegde; Subramanian, P.Item Nylon nets: a simple pest exclusion barrier technique to manage rhinoceros beetle menace in coconut plantations(2022) Sujithra, M; Rajkumar; Vinayaka Hegde; Subramanian, P.; Guru-Pirasanna-Pandi GovindharajOryctes rhinoceros (L.) is a major pest of palms worldwide. Seedlings and juvenile palms are more vulnerable to beetle damage and in severe cases, inflicting palm death. The present study was to develop a physical pest control technique for juvenile palms using nylon nets as a pest exclusion barrier. The unopened spear leaf with –two to four adjacent leaf bases were loosely wrapped with the nylon nets of different mesh size during June - December 2017 (N = 40). Results revealed that the damaged leaves were reduced from 61.02 to 7.53% (t = 17.23; p < 0.001). Further experiment was up scaled in 120 palms during June – December 2018 and the beetles trapped in nylon nets were recorded at weekly intervals. Nylon nets entrapped 618 adult beetles that comprised 61.80% females and 38.18% males with corresponding sex ratio of 1.61: 1. Thus, use of nylon nets as a pest exclusion barrier guarded the young palms from beetle attack and additionally acted as passive trap by entrapping 20.6 beetles/week/120 palms without any insecticidal intervention.