Epidemiology and Management of Turcicum leaf Blight of Maize Caused by Exserohilum turcicum (Pass.) Leonard and Suggs
Loading...
Files
Date
2005
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
UAS Dharwad
Abstract
Turcicum leaf blight disease of maize caused by Exserohilum turcicum symptoms
were recognized by long spindle shaped necrotic lesions with grey colour centre, immature
and chaffy ears. The disease appeared in severe form in most of the maize growing areas of
Karnataka.
Crop loss estimation studies revealed that, avoidable grain and stover yield losses in
susceptible genotype were to the extent of 52 and 40 per cent, respectively. Linear regression
crop loss models were developed. Arabhavi isolate recorded high virulence. Sixty-five days
old plants found vlnerability to infection. An incubation period of 28 hours was found ideal
for more than 90 per cent spore germination.
Saccharum arundinaceum Retz. was identified as a potential alternate host to E.
turcicum and plays an important role in the epidemiology of TLB in Karnataka.
Significantly maximum disease severity was noticed in crop sown on 16th September.
Crop sown between February and April found least affected. The weather factors viz.,
minimum temperature (11.3-21.40C), maximum temperature (26.3-29.40C), relative humidity
(58.7-84.5%) and rainfall (47.104 mm) were highly favourable for disease epidemic. The
locations viz., Arabhavi, Dharwad, Devihosur, Sankeshwar and Nagenahalli were identified
as ‘hot spots’ in Karnataka. Significant ad positive correlation existed between rainfall and
relative humidity with spore load.
The genotypes viz., Allrounder, IB-8501, Cargill 900M, Hi-Shell, NAC-6004, C-111,
KH-517, Kaveri 235 and NK-6240 were identified as slow blighters. The disease was
responsible for photosynthesis loss to the extent of 89.40 per cent in susceptible genotype.
Fourteen inbred lines registered as resistant sources. The QPM genotypes HQPM-4
and HQPM-5 found highly resistant.
Integration of tolerant hybrid DMH-2 and seed treatment with carboxin power (2
g/kg) or combined seed treatment with Azospirillum sp. (25 g/kg) and Trichoderma
harzianum (6 g/kg) followed by three sprays with mancozeb ( 0.25%) was found to be the
most effective IDM package.