MOLECULAR DETECTION, MECHANISM OF RESISTANCE AND MANAGEMENT OF LEAFHOPPERS IN PHYTOPLASMA ASSOCIATED SESAME PHYLLODY
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Date
2019-12-12
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UNIVERSITY OF AGRICULTURAL SCIENCES GKVK, BENGALURU
Abstract
The investigation on molecular detection, mechanism of resistance and
management of leafhoppers in phytoplasma associated sesame phyllody was undertaken
at college of Agriculture, V. C. Farm, Mandya and Department of Entomology, UAS,
GKVK, Bangalore from 2017 to 2019. The peak leafhopper population and incidence of
phyllody were noticed during second fortnight of April in Summer and first fortnight of
October in Kharif during 2017 and 2018, respectively.The phytoplasma was detected
from infested sesame plants and leafhoppers through molecular techniques using different
primers viz., P1/P7, SECA1/A2,Tuf and obtained 1.8kb, 840bp and 490 bp product size,
respectively. The genomic DNA of symptomatic plants and leafhoppers were found to be
associated with phytoplasma belongs to 16SrI ‘Candidatus phytoplasma asteris’group.
The detection of phytoplasma also confirmed using loop mediated amplification assay.
The field evaluation of twenty seven sesame genotypes against leafhoppers and phyllody
resulted in identifying four highly resistant genotypes. Among the biochemical
constituents studied for resistance and susceptibility, the total phenols showed significant
negative association with infestation, while, total sugars, reducing sugars, total free
amino acids and crude proteins indicated significant positive relationship with incidence
of phyllody. The studies on impact of feeding by leafhoppers on plant morphological and
biological attributes in different genotypes under controlled and open field conditions
revealed higher incidence, enzymes and nutrients levels in open field than controlled
condition. Among nine insecticides evaluated against leafhoppers and phyllody, seed
treatment with imidacloprid 48FS @ 5ml/kg with foliar spray of thiamethoxam 25WG @
0.3g/L was found effective in reducing incidence along with higher seed yield, net returns
and C: B ratio compared to other treatments.