EPIDEMIOLOGY AND MANAGEMENT OF TURCICUM LEAF BLIGHT (EXSEROHILUM TURCICUM (PASS.) LEONARD AND SUGGS) OF MAIZE IN JAMMU SUB-TROPICS
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Date
2015
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DIVISION OF PLANT PATHOLOGY, Sher-e-Kashmir University of Agricultural Sciences & Technology of Jammu, Main Campus, Chatha, Jammu 180009
Abstract
Survey for Turcicum blight of maize conducted during 2013 and 2014 in Jammu division
revealed that maximum disease intensity was observed in Udhampur district with the range of 37.30-
41.93% followed by Samba ranging from 29.28-32.07% disease intensity. However, minimum disease
was observed in Kathua district (24.71-25.76%). On the basis of prevalence of Turcicum blight of maize,
the districts were categorized as low (Kathua), medium (Samba and Jammu) and high disease
(Udhampur) districts. The isolates selected from different locations showed variation in colony growth
characteristics exibiting irregular/ profuse/ sparse or cottony growth. The colour of colonies ranged from
olivaceous grey to olivaceous brown with light black, dark greyish black, dark brown, and blackish
growth at centre. The number of septation in isolates ranged from 1 to 9 and spore size ranged from
71.8×21.2 to 121.5×21.1. The shape of spore observed were curved, elongated, spindle and the
pigmentation was red, grey and black. All the isolates Et1....Et12 showed excellent growth on PDA while
on V8 medium the isolates showed fair growth. The pathogenic reaction of different isolates were
categorized as per the scale and the isolates Et1, Et2 and Et4 recorded a score of 3.34 while ET3, ET5 and
Et8 scored 2.67. However, score of 2.75, was observed for isolates Et6, Et7, Et11 while Et9, Et10, Et12
recorded a score of 3.92.
Significant and positive correlation was observed between disease intensity and relative humidity
(maximum and minimum) and rainfall, significant and negative correlation with maximum temperature
and minimum temperature. Thirty six maize genotypes comprising composites, hybrids, inbreds line were
screened against Exserohilum turcicum under artificially inoculated field conditions and maximum
disease intensity was recorded in Super 1 (55.87) followed by C-8 (55.80). However, minimum disease
intensity was observed in Vivek maize hybrid (3.80%). Grain yields of different maize genotypes differed
significantly in protected and unprotected treatments. It was observed that the loss in grain yield varied
from 18.32 to 60.52% depending upon the disease severity in different genotypes. Genotype C-15
recorded significantly higher per cent loss in 1000 grain weight (23.12) followed by Bio 9262 white
(21.20).
In vitro studies revealed that Trichoderma harzianum (bio agent), Datura stramonium (leaf
extract), Propiconazole (systemic) and mancozeb (non systemic) were most effective in inhibiting
mycelial growth of E. turcicum. In field studies, Propiconazole showed maximum disease inhibition and
this treatment was at par with integrated treatment comprising of mancozeb (seed treatment) @ 0.25%,
Trichoderma harzianum (s.t) followed by foliar sprays of Datura stramonium extract (50%) and
mancozeb (f.s) which showed minimum disease incidence intensity (16.16%) coupled with maximum
yield of 39.52 q ha-1.
Description
Ph.D Thesis
Keywords
TURCICUM LEAF BLIGHT, EXSEROHILUM TURCICUM, VARIETAL SCREENING, BOTANICAL, BIOLOGICAL, CHEMICAL AND INTEGRATED DISEASE MANAGEMENT