Investigations on the variability and management of turcicum leaf blight in maize caused by Exserohilum turcicum (pass) leonard and suggs
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Date
2009
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UAS, Dharwad
Abstract
Turcicum leaf blight of maize caused by Exserohilum turcicum (Pass.) Leonard and
Suggs. is an important disease which results in heavy yield loss. Laboratory and field
experiments were carried out to study the pathogenic variability and management aspects of
the pathogen and disease. Survey indicated that, higher disease incidence was noticed in
Sankeshwer, Haveri, Arabhavi and Dharwad.
Eighteen isolates collected from different part of Northern Karnataka was studied in
the laboratory. Arabhavi isolate (Et5) was very fast growing with high rate of sporulation.
Among the five media studied potato dextrose agar (PDA) recorded maximum mycelial
growth of fungus followed by PDA + Yeast medium. Maximum growth of fungus was
observed at 300C in all the isolates followed by 250C temperature.
A botanical product, cristol 56 SL and systemic fungicide, carboxin 200 FF were most
effective in inhibiting the growth of the fungus. The plant extracts viz; nimbicidin and
negunda extract at 5 and 10 per cent concentration were effective against the pathogen.
Among the bio-control agents evaluated, Trichoderma harzianum found effective against the
pathogen.
Inbred lines viz., KDMI-13, CM-138, INDIMYT- 343, CM-501, CI-4, V-356, V-358,
NEI-9202B, NG-14 and hybrids viz., Swarna, NAC-6004, NK-6240, JKMH-502, PAC-740,
C-193 registered resistant reaction under artificial inoculate field condition. Seed treatment
with carboxin 200 FF @ 2 ml/kg or Trichoderma harzianum @ 6g/kg and foliar spray of
mancozeb 0.25% twice at 40 and 50 DAS, recorded minimum disease severity and highest
grain yield. Seed treatment with carboxin 200 FF 2ml/kg seed and 2 sprays of 0.25% cristol
56 SL at 40 to 50 DAS found equally effective.