INTRODUCTION
Garlic (Allium sativum) is one of the important bulb crop and is used as a spice throughout the world. It is belonging to the family Alliaceae and is commonly termed as ‘Lasan’ as well as botanically known as Allium sativum (Linnaeus). It is mainly used for culinary purposes and a condiment for different food items. Garlic is widely used around the world for its pungent flavor as a seasoning or condiment ingredient. It is a major spice crop in India. India is the second largest producer of garlic. Garlic bulb is used for consumption (raw or cooked) or for medicinal purposes [1]. Several diseases caused by fungi, bacteria, nematodes, and viruses play a major role in reducing the yield per unit area. Among the diseases leaf blight is a major disease of garlic caused by different species of Stemphylium [14]. The severity of the disease is much more where the crop is predisposed by thrips injury [4]. In favorable conditions, an epidemic may cause total failure of the crop caused by Stemphylium sp. Garlic yield was reduced by 30% on average, with up to 70% yield losses in some fields during the winter growing season. In view of this, the present study has planned to assess the effect of different fungicides as foliar sprays in controlling stemphylium blight disease of garlic.
MATERIAL AND METHODS
The experiment was piloted at the Research Farm of National Horticultural Research and Development Foundation (NHRDF), Regional Research Station (RRS) Nashik, Maharashtra for the two consecutive years during rabi season (2020-21 and 2021-22) on the Agrifound white variety of garlic. The raised bed 1.50m x 2.50m in size was made to plant the cloves at the space of 15.0cm x 10.0 cm. The trial was designed with Randomized Block Design with four replications. Three foliar sprays of fungicides were done, starting after 45 days of planting, at the interval of 15 days. The standard practices of agriculture were followed unvaryingly for all the treatments. Optimum moisture was maintained in soil through regular irrigation. The data was recorded for the incidence and intensity of stemphylium blight before each spray. Scoring of the disease was done on a scale of 0-5, while Percent Disease Index (PDI) or disease intensity was recorded as described by Wheeler [13] as given below. The percent disease control (PDC) for the stemphylium blight was also recorded. After attaining maturity crop was harvested from all the treatments for further assessment of yield.
Percent Disease Index (PDI) = X 100
Percent Disease Incidence = X 100
Details of treatments:
T1: Spray of Mancozeb @ 2.5 g/L at 45 DAP + Iprodione @ 2.5g/L at 60 DAP + Azoxystrobin + Cyproconazole @ 1.0 ml/L at 75 DAP
T2:Spray of Hexaconazole @ 2.0 g/L at 45 DAP + Tebuconazole + Trifloxostrobin @ 1.0g/L at 60 DAP +Fenamidone + Mancozeb @ 2.0ml/L at 75DAP
T3:Spray of Mancozeb @ 2.5 g/L at 45DAP + Chlorothalonil @ 2.0g/L at 60 DAP + Pyraclostrobin 5% + Metiram 55% @ 1.0 g/L @ at 75DAP
T4: Spray of Azoxystrobin + Cyproconazole @ 1.0ml/L at 45, 60 and 75DAP
T5: Spray of Mancozeb @ 2.5 g/L at 45, 60 and 75DAP
T6: Control (No spray)
RESULTS AND DISCUSSION
Rabi 2020-21
The data presented in Table-1 revealed that stemphylium blight disease has appeared after 60 days of planting. The incidence of stemphylium blight ranged from 25.0% to 55.0% and intensity varied from 1.60% to 11.0% during the cropping period. The significantly lowest stemphylium blight incidence (25.0%) as well as intensity (1.60%), was recorded in treatment T4 (Sprays of Azoxystrobin + Cyproconazole @ 1.0 ml/L at 45, 60 and 75 DAP) at 60 DAP. The disease progresses as per the advancement of the crop stage. Further, data revealed that, the significant lowest incidence (27.50%) as well as intensity (4.30%) was recorded in same treatment T4 at 75 DAP. The highest stemphylium blight incidence (55.0%) and intensity (11.0%) was recorded in T6 (Untreated control) at 75 DAP. The highest percent disease control (PDC) of stemphylium blight was recorded in treatment T4 (60.91%) followed by T3 (50.0%) and T2 (38.18%) over untreated control. The significantly highest gross yield (35.33 q/ha) as well as marketable yield (32.80 q/ha) was recorded in T4 which was found at par with all the treatments except untreated control. The lowest gross yield (27.20 q/ha) and marketable yield (24.06 q/ha) were recorded in T6 (Untreated control).
Table-1 In Vivo Evaluation of fungicides for the management of foliar diseases of garlic during Rabi, 2020-21
| Treatments | Stemphylium blight | #PDC | Gross Yield (q/ha) | Market-able Yield (q/ha) | |||||||
| At 60 DAP | At 75 DAP | ||||||||||
| *Incidence (%) | Intensity (%) | *Incidence (%) | Intensity (%) | ||||||||
| T1 | 32.50 | (34.72) | 2.90 | (1.84) | 45.00 | (42.12) | 8.00 | (2.91) | 27.27 | 34.00 | 31.60 |
| T2 | 30.00 | (33.05) | 2.50 | (1.72) | 40.00 | (39.17) | 6.80 | (2.70) | 38.18 | 34.07 | 31.83 |
| T3 | 30.00 | (33.05) | 2.20 | (1.64) | 35.00 | (36.22) | 5.50 | (2.45) | 50.00 | 34.20 | 32.60 |
| T4 | 25.00 | (29.89) | 1.60 | (1.45) | 27.50 | (31.55) | 4.30 | (2.19) | 60.91 | 35.33 | 32.80 |
| T5 | 35.00 | (36.22) | 3.40 | (1.97) | 52.50 | (46.44) | 9.70 | (3.19) | 11.82 | 33.20 | 29.56 |
| T6 | 42.50 | (40.67) | 4.40 | (2.21) | 55.00 | (47.88) | 11.00 | (3.39) | – | 27.20 | 24.06 |
| S.Em± | – | 2.08 | – | 0.08 | – | 2.24 | – | 0.11 | – | 2.17 | 2.65 |
| CD at 5% | – | 4.43 | – | 0.17 | – | 4.77 | – | 0.23 | – | 4.63 | 5.65 |
| CV % | – | 8.49 | – | 6.58 | – | 7.83 | – | 5.39 | – | 9.32 | 12.31 |
Note- Data in the parenthesis shows *arcsine/square root transformed values
# Percent Disease Control
Fig: 01
Rabi 2021-22
The data presented in Table-2 revealed that stemphylium blight disease has appeared after 60 days of planting. The incidence of stemphylium blight ranged from 15.0% to 67.50% and intensity varied from 1.20% to 13.50% during the cropping period. The significantly lowest stemphylium blight incidence (15.0%) as well as intensity (1.20%), was recorded in treatment T4 (Spray of Azoxystrobin + Cyproconazole @ 1.0 ml/L at 45, 60, and 75 DAP) at 60 DAP. The disease progresses as per the advancement of the crop stage. Further, data revealed that, the significantly lowest incidence (37.50%) as well as intensity (5.80%) was recorded in the same treatment T4 at 75 DAP. The highest stemphylium blight incidence (67.50%) and intensity (13.50%) was recorded in T6 (Untreated Control) at 75 DAP. The highest percent disease control of stemphylium blight was recorded in treatment T4 (57.04%) followed by T3 (47.41%) and T2 (37.78%) over T6 (Control). The significantly highest gross yield (95.21 q/ha) as well as marketable yield (92.85 q/ha), was recorded in T4. However, the gross yield was found at par with T2 (Spray of Hexaconazole @ 2.0 ml/L at 45 DAP, Tebuconazole + Trifloxystrobin @ 1.0 g/L at 60 DAP, Fenamidone + Mancozeb 2.0 g/L at 75 DAP) and T3, whereas, the marketable yield was found at par with T3.
Table-2 In-Vivo evaluation of fungicides for the management of foliar diseases of garlic during rabi, 2021-22
| Treatments | Stemphylium blight | #PDC | Gross yield (q/ha) | Market-able yield (q/ha) | |||||||
| At 60 DAP | At 75 DAP | ||||||||||
| *Incidence (%) | Intensity (%) | *Incidence (%) | Intensity (%) | ||||||||
| T1 | 35.00 | (36.22) | 2.70 | (1.79) | 55.00 | (47.88) | 9.70 | (3.19) | 28.15 | 79.80 | 75.49 |
| T2 | 25.00 | (29.89) | 1.80 | (1.52) | 50.00 | (45.00) | 8.40 | (2.98) | 37.78 | 84.65 | 77.08 |
| T3 | 20.00 | (26.57) | 1.60 | (1.45) | 45.00 | (42.12) | 7.10 | (2.75) | 47.41 | 85.76 | 82.57 |
| T4 | 15.00 | (22.50) | 1.20 | (1.30) | 37.50 | (37.73) | 5.80 | (2.51) | 57.04 | 95.21 | 92.85 |
| T5 | 30.00 | (33.21) | 2.30 | (1.67) | 62.50 | (52.27) | 11.30 | (3.43) | 16.30 | 79.23 | 73.33 |
| T6 | 47.50 | (43.56) | 7.50 | (2.82) | 67.50 | (55.28) | 13.50 | (3.74) | – | 72.08 | 68.05 |
| S.Em± | – | 1.96 | – | 0.09 | – | 2.18 | – | 0.09 | – | 5.61 | 6.72 |
| CD at 5% | – | 4.18 | – | 0.19 | – | 4.65 | – | 0.19 | – | 11.96 | 14.32 |
| CV % | – | 8.66 | – | 7.38 | – | 6.60 | – | 3.96 | – | 9.59 | 12.14 |
Note- Data in the parenthesis shows *arcsine/square root transformed values
# Percent Disease Control
Fig: 02
Combined data (2020-21 & 2021-22)
The combined data from two years of trials are presented in Table-3 revealed that stemphylium blight disease was appeared after 60 days of planting. The incidence of stemphylium blight ranged from 20.0% to 61.25% and intensity varied from 1.40% to 12.25% during the cropping period. The significantly lowest stemphylium blight incidence (20.0%) as well as intensity (1.40%), was recorded in treatment T4 at 60 DAP. The disease progresses as increasing the crop age. Further, data revealed that, the significantly lowest incidence (32.50%) as well as intensity (5.05%) was recorded in same treatment T4 at 75 DAP and the incidence was found at par with T3. The highest stemphylium blight incidence (61.25%) and intensity (12.25%) were recorded in T6 (Untreated Control) at 75 DAP. The highest percent disease control of stemphylium blight was recorded in treatment T4 (58.78%) followed by T3 (48.57%) and T2 (37.96%) over T6 (Control). The yield data shows non-significant variations, however, the highest gross yield (65.27 q/ha) as well as marketable yield (62.83 q/ha) were recorded in T4. The highest benefit-cost ratio (8.28:1) was recorded in T3 followed by T4 (5.89:1). Similar study has been done by Chaurasiaet. al. (2007) who reported that two to three spray of Dithane M-45 @ 0.3% and Bavistin @ 0.3% was effective against purple blotch disease of garlic as well as increased yield [3]. According to Gupta and Sharma (2017). soil application of Ps. fluorescens and foliar spray of Pyraclostrobin + Metiram was most effective for control of stemphylium blight in garlic [5]. Tebuconazole and procymidone have been reported to provide effective control of stemphylium leaf blight in garlic [2]. Singh et. al. (2021) reported that some bio-agents and botanicals were found most effective against foliar diseases of garlic [11]. Gupta et. al. (1996) reported that Stemphylium vesicarium is one of the major destructive diseases of onion crops grown in the state of Maharashtra [6]. Bio-efficacy of eight fungicides was evaluated in vitro against Stemphylium vesicarium. All the fungicides tested were found fungicidal against the pathogen and inhibited mycelial growth of the pathogen over untreated control. Srivastava et. al., reported that Chlorothalonil 75 WP, Difenoconazole 25 EC, thiophanate methyl 70 WP, Penconazole 10 EC. and Hexaconazole 5 EC were promising for effective management of Stemphylium leaf blight of garlic [12]. Jakhar et. al. (1996) reported that fungicide Mancozeb and Copper oxychloride have been the most effective and economical fungicides against stemphylium blight and purple blotch disease in vitro as well as under in vivo conditions [7]. Pandey et. al. (2022, 2023a and 2023b) reported that combined fungicides and the alternative spray of bio-agents as well as fungicides are more effective against stemphylium blight of onion and increased the bulb yield [8] [9] [10].
Table-3 In-Vivo evaluation of fungicides for the management of foliar diseases of garlic (Combined rabi, 2020-21 &2021-22)
| Treatments | Stemphylium blight | Gross yield (q/ha) | Market-able yield (q/ha) | B:C ratio | ||||||||
| At 60 DAP | At 75 DAP | #PDC | ||||||||||
| *Incidence (%) | Intensity (%) | *Incidence (%) | Intensity (%) | |||||||||
| T1 | 33.75 | (35.51) | 2.80 | (1.82) | 50.00 | (45.00) | 8.85 | (3.05) | 27.76 | 56.90 | 53.54 | 2.75:1 |
| T2 | 27.50 | (31.61) | 2.15 | (1.62) | 45.00 | (42.12) | 7.60 | (2.84) | 37.96 | 59.36 | 54.46 | 3.21:1 |
| T3 | 25.00 | (29.89) | 1.90 | (1.55) | 40.00 | (39.20) | 6.30 | (2.60) | 48.57 | 59.98 | 57.58 | 8.28:1 |
| T4 | 20.00 | (26.39) | 1.40 | (1.38) | 32.50 | (34.69) | 5.05 | (2.35) | 58.78 | 65.27 | 62.82 | 5.89:1 |
| T5 | 32.50 | (34.74) | 2.85 | (1.82) | 57.50 | (49.34) | 10.50 | (3.31) | 14.29 | 56.22 | 51.44 | 5.52:1 |
| T6 | 45.00 | (42.13) | 5.95 | (2.52) | 61.25 | (51.56) | 12.25 | (3.57) | – | 49.64 | 46.06 | – |
| S.Em± | – | 2.86 | – | 0.12 | – | 3.13 | – | 0.14 | – | 6.02 | 7.22 | – |
| CD at 5% | – | 7.35 | – | 0.31 | – | 8.05 | – | 0.36 | – | NS | NS | – |
Note- Data in the parenthesis shows *arcsine/square root transformed values
# Percent Disease Control
Fig: 03
CONCLUSION
The combined data of two years trial conducted during rabi, 2020-21 and 2021-22 on garlic variety Agrifound White revealed that foliar spray of Azoxystrobin + Cyproconazole @ 1.0 ml/L at 45, 60 and 75 days after planting performed superior for the management of foliar diseases with 58.78% disease control of stemphylium blight over untreated control with benefit cost ratio of 5.89:1 in this treatment. Farmers are suggested to use of Azoxystrobin + Cyproconazole fungicide @ 1.0 ml/L at 45, 60 and 75 days after planting for improved their yield and quality of garlic. Resistancy developed in the garlic against different diseases is due to the continuous spray of the same chemicals repeatedly and there is strong probability that if there is alternative use of chemicals on a schedule basis will help in minimizing the disease incidence as well as intensity and this scheduling must be analyzed in the field using different combinations and schedules for recommendation to the farmers.
ACKNOWLEDGEMENTS
The authors are thankful to the Additional Director, National Horticultural Research and Development Foundation (NHRDF) for providing all the necessary facilities. I also thanks to my co-authors who helped me during the entire research and manuscript preparation.
REFERENCES