Studies on Turcicum Leaf Blight and Common Rust Diseases of Sweet Corn (Zea mays L. saccharata)
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Date
2018-07
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University of Agricultural Sciences, Dharwad
Abstract
An investigation was undertaken on loss assessment, epidemiology, screening and management of turcicum leaf blight (TLB) (Exserohilum turcicum (Pass.) Leonard
and Suggs.) and common rus t (Puccinia sorghi Schw.) diseases of sweet corn at Main Agricultural Research Station, UAS, Dharwad.
Roving survey carried out during kharif, 2017 in Bagalkote, Belagavi, Dharwad and Chikkaballapur districts indicated, maximum mean severity of TLB (56.54 %) and
minimum severity of common rust (37.81 %) were observed in Chikkaballapur district. Maximum mean severity of common rust (43.73 %) and minimum severity of TLB (49.00 %) were noticed in Belagavi district.
Crop loss estimation studies revealed that, avoidable green ear and fodder yield losses in susceptible genotype were to an extent of 33.90 and 40.40 per cent,
respectively. Five sprays of tebuconazole 250 % EC @ 0.1 % recorded least severity of TLB (5.35 %) and common rust (3.04 %) diseases.
The weather factors, viz., maximum temperature (27.0oC to 29.1oC), minimum temperature (19.8oC to 21.3oC), relative humidity (>90.0 %) and rainfall (103.0 mm to 233.8 mm) were congenial for development of both the diseases. Rainfall and number of rainy days were significantly positively correlated with the severity of both the TLB and common rust. The regression models developed were, Y = 16.101- 0.098 X5+ 4.159 X6 with R2 = 0.97 for TLB and Y = -4.771-0.102 X5+ 3.547 X6 with R2 = 0.95 for common rust.
Among 33 genotypes screened, one genotype, SW-3 was found resistant against common rust but none of the genotypes found resistant for TLB. Genotypes, SW-2 and Hibrix-39 registered moderately resistant reaction for both the diseases. Foliar spray with tebuconazole 250 % EC @ 0.1 % at 35 and 50 days after sowing was effective in managing both the diseases and recorded maximum green ear yield (16.35 t/ha) with highest B:C ratio (2.75).