Comparative analysis of various spraying schedules through seven fungicides under natural condition against Alternaria blight of cluster bean were evaluated. This experiment was conducted during
Kharif-2019, 2020 year.
Effect of fungicidal spray at initiation of flowering stage of cluster bean
The results of the experiment conducted during 2019-20 revealed that all the treatments were found effective against Alternaria blight of cluster bean over control. The minimum per-cent disease index (PDI) of 9.87 was recorded in Tebuconazole followed by Chlrothalonil, Hexaconazole and Difenoconazole with PDI of 13.60, 16.53 and 21.87 respectively, while maximum (41.60) PDI was recorded in control (Table 1).
During the year 2020 the results reveals that the minimum per-cent disease index was recorded in Tebuconazole (11.13%) followed by chlrothalonil (13.07%), Propiconazole (13.73%), Trifloxystrobin (14.27%), Difenoconazole (16.20%), Mancozeb (17.07%) and Hexaconazole (19.07%), while maximum PDI was recorded in control (40.47%).
The two year pooled data reveals that the minimum percent disease index was recorded in Tebuconazole (10.50%) followed by Chlrothalonil (13.34%), Hexaconazole (17.80%), Difeconazole (19.04%), Mancozeb (19.47%), Propiconazole (20.07 %), Trifloxystrobin (25.40%), while maximum intensity was recorded in control (41.14%). However, treatment T3
i.e. foliar spray with Tebuconazole 250 EC @ 0.1 % was proven as the most effective treatment for the management of alternaria leaf blight at initiation of flowering. (Fig 1 and Fig 2)
Effect of fungicidal spray at poding stage of cluster bean
The findings of the year 2019 showed that all treatments significantly reduced the percentage of disease intensity compared to the control at pod formation stage. The minimum percent index was recorded in Tebuconazole (12.00%) followed by Chlrothalonil (16.00%), Hexaconazole (18.93%), Mancozeb (24.00%), Difenconazole (24.80%), Propiconazole (29.60%) and Trifloxystrobin (41.33%), while maximum disease index (PDI) was recorded in control (44.00%).
In the experimental year 2020 the minimum PDI was recorded in Tebuconazole (13.92%) followed by Chlrothalonil (17.68%), Propiconazole (18.13%), Trifloxystrobin (20.47%), Difeconazole (21.00%), Mancozeb (22.80%), Hexaconazole (26.20%), while maximum (PDI) was recorded in control (52.87%).
The two year pooled data indicate that the minimum (PDI) was recorded in Tebuconazole (12.96%) followed by Chlrothalonil (16.84%), Hexaconazole (22.57%), Difeconazole (22.90%), Mancozeb (23.40%), Propiconazole (23.87%), Trifloxystrobin (30.90%), while maximum intensity was recorded in control (48.44%). However, foliar spray with Tebuconazole 250 EC @ 0.1% was found most effective at poding stage.
Effect of fungicidal spray on grain Yield (kg/ha) of cluster bean
In the year 2019, data reveals that all the treatments were found effective against Alternaria disease of cluster bean over control. Maximum grain yield was recorded in treatment Tebuconazole (2077 kg/ha) followed by Chlrothalonil (1909 kg/ha), Hexaconazole (1670 kg/ha), Mancozeb (1613 kg/ha), Difenoconazole (1511 kg/ha), Propiconazole (1412 kg/ha) and Trifloxystrobin (1385 kg/ha), while minimum grain yield was recorded in control (1272 kg/ha).
Similarly in year 2020 result reveals that the maximum grain yield was recorded in Tebuconazole (2613 kg/ha) followed by Chlrothalonil (2428 kg/ha), Propiconazole (2387 kg/ha), Trifloxystrobin (2346 kg/ha), Difenoconazole (2099 kg/ha), Mancozeb (2038 kg/ha), Hexaconazole (1831 kg/ha), while minimum grain yield was recorded in control (1770 kg/ha).
According to findings of a two year pooled investigation on documented in Table 1. The maximum grain yield was recorded in Tebuconazole (2345.00 kg/ha) followed by Chlrothalonil (2168.50 kg/ha), Propiconazole (1899.50 kg/ha), Trifloxystrobin (1865.50 kg/ha), Mancozeb (1825.50 kg/ha), Difenoconazole (1805.00 kg/ha), Hexaconazole (1750.50 kg/ha), while minimum grain yield was recorded in control (1521.00 kg/ha). However, foliar spray with Tebuconazole 250 EC @ 0.1% was found most effective as in terms of grain yield.
Effect of fungicidal spray on straw yield of cluster bean
During 2019 data summizered in Table 1. reveals that all the treatments were found effective against Alternaria disease of cluster bean over control. Maximum straw yield was recorded in treatment Tebuconazole (3994 kg/ha) with highest B: C ratio 4.55 followed by Hexaconazole (3268 kg/ha), Chlrothalonil (3147 kg/ha), Mancozeb, Difeconazole (2905 kg/ha), respectively and Propiconazole, Trifloxystrobin (2663 kg/ha), while minimum straw yield was recorded in control (2469 kg/ha).
During 2020 the similar trends for (Table 1) was recorded with highest straw yield in Tebuconazole (4321 kg/ha) with highest B: C ratio of 4.73 followed by Propiconazole (3395 kg/ha), Chlrothalonil (3230 kg/ha), Trifloxystrobin (3189 kg/ha), Mancozeb (3128 kg/ha), Hexaconazole (2798 kg/ha), Difeconazole (2572 kg/ha), while minimum straw yield was recorded in control (2608 kg/ha).
The two year pooled data indicates that maximum straw yield was recorded in Tebuconazole (4157.50 kg/ha) followed by Chlrothalonil (3188.50 kg/ha), Hexaconazole (3033.00 kg/ha), Propiconazole (3029.00 kg/ha), Mancozeb (3016.50 kg/ha), Trifloxystrobin (2926.00 kg/ha), Difeconazole (2738.50 kg/ha), while minimum grain yield was recorded in control (2538.50 kg/ha). However, in treatment with foliar spray Tebuconazole 250 EC @ 0.1% the highest B: C ratio of 4.55 and 4.73 was recorded.
Discussion
Disease severity of Alternaria leaf blight of cluster bean is recorded during experimental years and the PDI of leaf spot was significantly reduced in plants sprayed with Tebuconazole 250 EC, Mancozeb, Propiconazole and Trifloxystrobin as compared to control, plant sprayed with water. The result showed that the mean infection on leaves ranged from 10.50 to 41.14 and 12.96 to 48.44% respectively when the data was recorded during the application of fungicides at initiation of flowering and poding stage. However, significantly maximum reduction percent in severity of alternaria leaf blight was recorded in case of tebuconazole 250EC. Similar finding is also given by
Anupriya et al., (2020). Thaware et al., (2011) also reported that Mancozeb (0.2%) and Propiconazole (0.05%) totally suppressed the growth of
A. alternate, which causes cowpea leaf spot. The data showed highly significant difference between treatments for yield of cluster bean infected with alternaria leaf blight. The data (Table 1) showed that the significantly lowest yield of grain and straw 1521 and 2538 kg/ha was recorded in control, while highest yields were obtained from plot treated with tebuconazole. The finding are in agreement with the
Tomar et al., (2005) also reported the increase of seed yields of cluster bean with the management of disease through fungicides.