National Plant Protection Center

Thimphu, Bhutan

National Plant Protection Center

Thimphu, Bhutan
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Om N.,University of Western Sydney | Om N.,National Plant Protection Center | Yefremova Z.A.,Tel Aviv University | Yegorenkova E.N.,Ulyanovsk State Pedagogical University | And 3 more authors.
Journal of Asia-Pacific Entomology | Year: 2017

Parasitised nymphs of Diaphorina communis, a host of ‘Candidatus Liberibacter asiaticus’, were observed on Bergera koenigii in the Wangdue Phodrang Dzongkhag, Bhutan, and parasitised nymphs of Diaphorina citri were found on Murraya paniculata in the Chukhha Dzongkhag. The nymphs of both hosts were collected along with leaf tissue and placed individually in gelatine capsules. Emerging parasitoids were preserved in ethanol and used either for DNA extraction or morphological examination. Molecular and phylogenetic analyses of the sequence data of the COI, ITS1 and ITS2 regions showed that the parasitoids from the two hosts belonged to two different clades. Morphological examination confirmed that the parasitoids belong to two separate species of Tamarixia, and that the parasitoid from Diaphorina communis is a new species. This is the first record of an ectoparasitoid of Diaphorina communis, and the parasitoid has been named Tamarixia drukyulensis sp. n. The molecular and phylogenetic studies also suggest the occurrence of a eulophid parasitoid or hyperparasitoid of Diaphorina communis belonging to the genus, Aprostocetus. © 2017

Donovan N.J.,Australian Department of Primary Industries and Fisheries | Beattie G.A.C.,University of Western Sydney | Chambers G.A.,Australian Department of Primary Industries and Fisheries | Holford P.,University of Western Sydney | And 4 more authors.
Australasian Plant Disease Notes | Year: 2012

Huanglongbing (HLB) or citrus greening is one of the most destructive diseases of citrus in the world and one of the major factors limiting citrus production in south east Asia including Bhutan. The presence of 'Candidatus Liberibacter asiaticus', associated with the Asiatic form of HLB, was confirmed by conventional and real-time PCR in adults of the black psyllid, Diaphorina communis Mathur. This is the first formal detection of 'Ca. L. asiaticus' in D. communis, and the first detection of the pathogen in a psyllid other than D. citri Kuwayama in Asia, excluding Arabia. This study is also the first to report the presence of D. communis in Bhutan. © 2011 Australasian Plant Pathology Society Inc.

Matsushita K.,Japan National Agricultural Research Center | Yasuda N.,Japan National Agricultural Research Center | Thinlay,National Plant Protection Center | Koizumi S.,Japan National Agricultural Research Center | And 6 more authors.
Euphytica | Year: 2011

The rice cultivar 'Chumroo' is commonly cultivated in the mid- and high-altitude areas of Bhutan. This cultivar has shown durable blast resistance in that area, without evidence of breakdown, for over 20 years. Chumroo was inoculated with 22 blast isolates selected from the race differential standard set of Japan. The cultivar showed resistance to all the isolates. To identify the resistance gene(s), Chumroo was crossed with a susceptible rice cultivar, Koshihikari. The F1 plants of the cross showed resistance. Segregation analyses of 300 F3 family lines fitted the segregation ratio of 1:2:1 and indicated that a single dominant gene controls the resistance to a blast isolate Ao 92-06-2 (race 337. 1). The Chumroo resistance locus (termed Pi46(t)) was mapped between two SSR markers, RM6748 and RM5473, on the terminal region of the long arm of chromosome 4, using linkage analysis with SSR markers. The nearest marker, RM5473, was linked to the putative resistance locus at a map distance of 3. 2 cM. At the chromosomal region, no true resistance genes were identified, whereas two field resistance genes were present. Therefore, we designated Pi46(t) as a novel blast resistance locus. © 2011 Springer Science+Business Media B.V.

Mahat K.,National Plant Protection Center | Drew R.A.I.,Griffith University
Acta Horticulturae | Year: 2015

The use of malathion in fruit fly protein bait sprays has raised serious concerns due to its adverse effects on non-target organisms. This has necessitated the evaluation of novel reduced-risk compounds. This study evaluated the effects of spinosad, fipronil, malathion and chlorpyrifos mixed with fruit fly protein bait (Mauri Pinnacle protein®) on attraction, feeding and mortality of the Queensland fruit fly, Bactrocera tryoni (Froggatt). The effects of outdoor weathering of these mixtures on fly mortality were also determined. In field-cage experiment, proteinstarved flies showed the same level of attraction to baits containing spinosad, fipronil, malathion, chlorpyrifos and protein alone used as control. Female proteinstarved flies were deterred from feeding on baits containing malathion and chlorpyrifos compared to baits containing spinosad, fipronil and protein alone. Baits containing malathion and chlorpyrifos caused higher fly mortality and rapid fly knock down than spinosad and fipronil. However, spinosad acted slowly and caused an increase in fly mortality over time, causing up to 90% fly mortality after 72-h. Baits containing malathion and chlorpyrifos, applied on citrus leaves and weathered outdoors, had longer residual effectiveness in killing flies than spinosad and fipronil. Residual effectiveness of the spinosad bait mixture waned significantly after 3 days of outdoor weathering. Results suggest that spinosad and fipronil can be potential alternatives for malathion in protein bait sprays.

Holford P.,University of Western Sydney | Donovan N.J.,Elizabeth Macarthur Agricultural Institute | Thinlay,National Plant Protection Center | Kabanoff E.,University of Western Sydney | And 6 more authors.
Australasian Plant Disease Notes | Year: 2010

Powdery mildew is one of the most important diseases of citrus in Bhutan where it infects new flush growth causing leaf and shoot distortion and twig and branch dieback. It also attacks young fruitlets. This causes premature fruit drop. These symptoms, together with DNA sequence data and the production of single conidia and lobed appressoria, suggest that the disease is caused by Oidium citri (JM Yen) U. Braun. This is the first formal report of this pathogen in Bhutan. © Australasian Plant Pathology ociety 2010.

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