Studies on Loss Assessment and Management of Common Rust of Maize Caused by Puccinia sorghi Schw.
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Date
2011
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UAS, Dharwad
Abstract
Common rust of maize caused by Puccinia sorghi Schw. is an important
disease which results in heavy yield loss. Laboratory and field experiments were
carried out to study the loss assessment and management aspects of the disease. Spore
germination was maximum within 24 hr at temperature in the range of 20-30°C. The
maximum spore germination was recorded at 25°C (66.16%) which is statistically on
par at 30°C.
Differential spray schedule with Hexaconazole 0.1% revealed that, rust index
was least in T5, i.e., five sprays of Hexaconazole (30.25%) and the disease was
completely free with T6, i.e., six sprays of Hexaconazole. Maximum grain yield
(35.58 q/ha) was obtained with six sprays of Hexaconazole. Highest per cent
avoidable grain yield loss was recorded with six sprays of 0.1% Hexaconazole
(60.53%) over untreated control. This indicates that common rust disease can cause
up to 60.53 % yield loss in susceptible cultivar CM-202.
The disease development started on 30 days (22.34% PDI) and increased
progressively up to 90 days (88.56% PDI) and later on became stable. Maximum rust
severity of 89.82 per cent was observed on 60 days old plants which was on par with
70 days (89.61%) and was significantly superior to rest of the plant age group.
Among the inbred lines MI-12 and Indimyt-345 are highly resistant to
common rust of maize and among hybrids viz., NK-6240, NK-61, NK-7305, CP-808,
GK-3090, 30R77, CP-818, C-1945, JKMH-502, PAC-740, NK-121, Pro-311, DK-984
and Swarna registered resistant reaction under artificial inoculated field condition.
A systemic fungicide, Tebuconazole 250 EC and nonsystemic fungicide,
Mancozeb + Phyton and botanical product, Neemazol F 5% were most effective
which resulted in less per cent germination of uredospore.
The ITK’s viz; Jeevamrutha @ 20 per cent concentration caused significantly
less per cent germination (22.69%). Among the bio-control agents evaluated,
Trichoderma harzianum was found effective against the pathogen.
Significantly minimum PDI (19.74%) and maximum grain yield (66.87 q/ha)
was recorded in treatment T1, i.e., foliar application of Tebuconazole @ 0.1% at 35
and 50 DAS.