PNABD246.pdf

*0427 Sud, V.K. ; Singh, B.M. 1984. Effect of environmental factors on the
development of leaf spot (Cercospora canescens) in urdbean. INDIAN
PHYTOPATHOLOGY, v.37(3):511-515. [En] [En Abstj (A:PS)
The rapid development of leaf spot, caused by Cercospora canescens in
blackgram (Vigna mungo), was favored by a mean temp. of 22.5-23.5 C, relative
humidity of 77-85X, more than 5 sunshine hours/day and more rainy days.
Intermittent rains were found to be favorable for disease development. Heavy
rainfall or continuous dry spells were not conducive to disease development.
Infection periods characterized by more rainy days combined with more sunshine
hours were conducive for disease development. [ASj
*0428 Ahmad, Q. 1985. Fungicidal control of Cercospora leaf spot of
mungbean (Vigna radiata). INDIAN PHYTOPATHOLOGY, v.38(3):418-422. [En] [En
Abst] (A:PS)
Seed treatment with bavistin 50 WP (at the rate of I g/kg seed) followed by
a single spray of bavistin 50 WP (0.05%) as soon as Cercospora leaf spot of
mungbean (Vigna radiata) appeared, significantly reduced the disease intensity
and increased the grain yield by 361 kg/ha over control. This provided a net
additional income of Rs. 1220.4b per hectare over control. The return per rupee
of total investment of bavistin was Rs. 3.36. [AS]
*0429 Rao, P.B. ; Mallaiah, K.V. 1985. Factors affecting conidial
germination in Cercospora canescens pathogenic to blackgram. INDIAN
PHYTOPATHOLOGY, v.38(3):559-560. [EnJ (A:PS)
Effect of some environmental factor on conidial germination of the
Cercospora canescens are presented in this paper. Germination was observed at
temperature from 10 to 30 C. Conidia failed to germinate at temper-ture 0, 5,
and 40 C. Optimum temperature for conidial germination and germtube growth was
25 C. At 30 C though 96% germination was observed, the germtube growth was very
less (84.14 um) when compared to 25 C (227.78 um). The apical cell are devoid
of germtubes at 66 and 75% RH levels. Germination was higher in free water
(96%) than at 100/ RH level (86%). Maximum germtube growth (148.6 um) was
observed in free water. White light favors conidial germination (92%) and
germtube growth (181.44 um). Red light inhibited germination, no effect on
germtube growth. Violet light favoured the emergence of germtubes from
intercalary cells. The maximum germination (95%) was observed at pH 5.0 and
7.0, but germtube growth was favoured by pH 5.0 (301.14 um). [PLH]
*0430 Sud, V.K. ; Singh, B.M. 1985. Relationship between severity of
Cercospora canescens on urdbean (Vigna mungo) and loss in grain yield. INDIAN
PHYTOPATHOLOGY, v.38(3):435-441. [Enj [En Abstj (A:PS)
Estimation of yield losses due to Cercospora canescens in blackgram
cultivar Kulu 4 was made in field trials with simulated epidemics of early and
late duration with slow and fast disease development. Yield losses were
proportional to disease severities at 50% flowering in one year but varied
considerably during others. Yield loss was proportional to disease severity at
flowering stage for high and low progressions of disease but not for the
intermediate growth curves. Increase in disease severity past 50% of the
flowering does not significantly alter the yield. Infection rates were observed
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