The experiment was conducted at Main Agricultural Research Station, University of Agricultural Sciences, Dharwad during
Rabi 2017. The recommended package of practices
viz., Farm yard manure at the rate of 20 t ha
-1 and fertilizers Urea, SSP (Single Super Phosphate), MOP (Muriate of Potash) at the rate of 25, 75 and 60 kg ha
-1, respectively were used. The whole amount of SSP and MOP; half amount of urea were applied as basal dose before sowing of seeds. The rest amount of urea was applied at 30 days after sowing (DAS). The experiment was laid out in a randomized complete block design (RCBD). The seeds of cluster bean cv. Pusa Navbahar were sown on the main field by following spacing of 30×15 cm and with plot size of 3 m× 3 m. Light irrigation was given immediately after sowing.
Based on the studies of
Vijaykumar et al., (2021), Wettable sulphur (Sulfex 80% WP), hexaconazole (Contaf 5 EC), tebunconazole 50% + trifloxystrobin 25% WG (Nativo75% WG), nimbecidine (Azadirachtin 0.03%) and
Bacillus subtilis (MT383652.1) were selected for field experiment.
Two sprays were given as per the combination and schedule along with unsprayed control to know their efficacy in managing the powdery mildew under natural epiphytotic condition. The first spray was done immediately after the onset of disease (35 DAS) followed by second spray at 15 days interval. The disease severity was recorded at 15 days after second spray on five randomly selected plants per plot. In each plant, 5 leaves from lower, middle and upper part of the plant were graded by using 0-9 scale
(Mayee and Datar, 1986) and expressed as per cent disease index (PDI). Per cent reduction of disease over control and per cent increase in yield over control were also computed and presented in the Table 1.
Disease scoring scale
Score Description
0 No symptom of powdery mildew on leaves.
1 Small scattered powdery mildew specks covering 1% or less leaf area.
3 Small powdery lesions covering 1-10 % of leaf area.
5 Powdery lesions enlarged covering 11-25 % of leaf area.
7 Powdery lesions coalesce to form big patches covering 26-50 % leaf area.
9 Big powdery patches covering 51 % or more leaf area and defoliation occur.
Per cent disease index was calculated by using formula given by Wheeler (1969).
Green tender pods harvested at different intervals from each plot and pod yield per plot was converted into tonnes per hectare. Finally the cost of production was analyzed in order to find out the most economic treatment of different management practices. Cost and return analysis were done according to the procedure of
Kushwah et al., (2017) and
Bhupender et al., (2020). The benefit cost ratio (BCR) was calculated as follows:
For analyzing the experimental data, arcsine angular transformations were made and the data analyzed with ANOVA in randomized completely block design using IBM SPSS statistics 21 to test for significant difference among the treatments. In the study, observed significant differences at 5% level of significance (P value>0.05) for per cent disease index and yield at different treatments (
Walter, 1967).