EFFICACY OF FUNGICIDES TO CONTROL WHITE RUST (ALBUGO OCCIDENTALIS) OF RED AMARANTH (AMARANTHUS SP.)

Authors: M. M. R. Talukder1, M. Riazuddin2, M. M. Rahman2, M. S. Uddin2 and M. S. I Khan2

Abstract

M. R. Talukder, M. Riazuddin, M. M. Rahman, M. S. Uddin and M. S. I Khan. 2012. Efficacy of fungicides to control white rust (Albugo occidentalis) of red amaranth (Amaranthus Sp.). Bangladesh J. Plant Pathol. 28(1&2):1-4.

A field experiment was carried out to evaluate the efficacy of six fungicides to control white rust (Albugo occidentalis) of red amaranth (Amaranthus sp.). The fungicides were Sunvit @ 0.2%, Ridomil gold 68 WP (Chlorothalonil + Mefenoxam) @ 0.2%, Contaf 25 EC (Triazole) @ 0.1%, Orzim 50 WP (0.1%), Zoom 50 WP (0.1%), and X-tra care 300 EC (myclobutanil) % 0.05%. These were applied as foliar spray. The fungicides caused 8.18-70.28% reduction in severity in terms of percent disease index of white rust. On the contrary, the fungicides gave 22.31-110.50% increase in red amaranth fresh yield and 8.06-27.42% increase in 1000-seed weight. Among six fungicides tested, the most effective one to control white rust and to increase yield of red amaranth was Ridomil gold followed by Sunvit. Based on the findings of the present investigation Ridomil Gold 68 WP @ 0.2% foliar spray may be recommended to control white rust of red amaranth.

Want create site? Find Free WordPress Themes and plugins.

INTRODUCTION

Red amaranth (Amaranthus sp.) is a widely grown leafy vegetable crop in Africa and Asia. It is an annual, fast growing plant and is easily cultivated in homestead gardens and fields. Amaranth is a rich source of calcium, iron, and vitamins A and C. Red amaranth is also one of the important leafy vegetables in Bangladesh. The crop is attacked by about a dozen of diseases in the country (Talukder 1974, Anon. 1984). Among them white rust caused by Albugo occidentalis is noted as the major one considering its high incidence, wide distribution and adverse effect on yield and quality of the crop. It causes defoliation and withering of whole plant and also reduces market value. The Oomycetous fungus, A. occidentalis is known to be present wherever red amaranth is grown (Nyvall 1989). When the infection is confined to leaves it may not result in any appreciable yield loss (Kolte 1985). However, the presence of conspicuous white pustules at the vegetative stage can be of serious concern to farmers. A number of chemicals have been suggested to control the disease in India (Verma and Petrie 1979). In Bangladesh, recommendation for effective control of the disease is not available.

The present experiment was conducted to test some available fungicides against white rust of red amaranth with a view to select an effective fungicide to control the disease.

 

MATERIALS AND METHODS

Six fungicides namely Sunvit (0.2%), Ridomil gold 68 WP ((Chlorothalonil + Mefenoxam @ 0.2%), Contaf 25 EC (Triazole @ 0.01%), Orzim 50WP (0.01%), Zoom 50 WP (0.01%), X-Tra care 300 EC (0.05%) were tested against white rust of red amaranth under natural field condition. The experiment was conducted in the experimental farm of Regional Agricultural Research Station (RARS), Rahmatpur, Barisal during 2008-2009, 2009-2010, 2010-2011. The experimental plots were prepared following standard procedures and standard doses of manure and fertilizers were used. The experiment was laid out in a randomized complete block design with 3 replications, 2 m x 2 m unit plot and 1m distance between blocks and plots. Seeds of an amaranth variety BARI Lal shak-1 were sown in continuous lines maintaining 50 cm line to line distance. The fungicides were suspended in tap water and applied as foliar spray for 3 times starting from appearance of the disease with 15 days interval. Plants in control plots were sprayed with plain water. Fifteen days after last spray, the severity of white rust was indexed on a 0-5 rating scale (Mehta and Mondal 1978), where 0 = No infection, 1 = 10% leaf area infected, 2 = 11-30% leaf area infected, 3 = 31-50% leaf area infected, 4 = 51-70 % leaf area infected and 5 = 71% and above leaf area infected. The disease severity was expressed in percent disease index (PDI). The PDI was computed following a standard formula as shown below:

When amaranth plants were suitable for harvest as vegetable, an area of 1 m2 were randomly selected from each unit plot and harvested. Fresh weight of harvested red amaranth was measured and the yield was expressed as g/m2. After maturation, seeds were also harvested from an area of 1 m2 per plot. The yield of amaranth vegetable and seeds were expressed in kg/ha. Collected data were analyzed following standard statistical procedure (Gomez and Gomez 1983). Treatment means were compared using DMRT (Zaman et al. 1982).

 

RESULTS AND DISCUSSION

The highest PDI of 73.40, 77.74 and 82.40 was recorded from control plot respectively in first, second and third years. All treatments caused significant reduction in disease severity compared to control. Every year, significantly the lowest PDI was obtained with Ridomil gold followed by Sunvit. Efficacy of two fungicides to reduce the PDI was significantly different. The PDI under Contaf 25EC, Orzim 50WP, Zoom 50WP and X-Tra Care 300EC ranged 47.43-68.28 in first year, 46.03-67.91 in second year and 45.43-69.60 in third year. On an average the four fungicides gave 40.52, 30.34, 19.50 and 8.18% reduction in PDI over control. However, their efficacy was not consistent in every year    (Table 1).

Average yield of red amaranth (vegetable) recorded from control plot was 195.66, 188.00 and 205.00 kg/ha during 2008-2009, 2009-2010 and 2010-2011, respectively. Due to foliar spray with the test fungicides, the yield was increased to 245.50-425.66, 233.50-410.45 and 241.00-403.00kg/ha, respectively. The increase in yield obtained with each of the fungicides was significant compared to control. The highest and the lowest yield were recorded from the treatments with Ridomil gold and X-Tra Care, respectively. The second highest yield was obtained with Sunvit, which was statistically similar to Contaf and Orzim. Efficacy Zoom to increase yield was not significantly different form X-Tra Care (Table 2

In three consecutive years, seed size in terms of 1000-seed weight of red amaranth increased significantly over control due to foliar spray with different fungicides to control white rust disease of the crop. Significantly the highest 1000-seed weight was achieved with Ridomil gold. The second highest 1000-seed weight recorded from the treatment with Contaf, which was statistically similar to Orzim, Zoom and X-Tra care. The lowest yield increase was observed under the treatments with Sunvit, which was not significantly different from Orzim, Zoom and X-Tra care (Table 3)

1-1

In three consecutive years, seed size in terms of 1000-seed weight of red amaranth increased significantly over control due to foliar spray with different fungicides to control white rust disease of the crop. Significantly the highest 1000-seed weight was achieved with Ridomil gold. The second highest 1000-seed weight recorded from the treatment with Contaf, which was statistically similar to Orzim, Zoom and X-Tra care. The lowest yield increase was observed under the treatments with Sunvit, which was not significantly different from Orzim, Zoom and X-Tra care (Table 3)

1-2

Results of the present study reveal that Ridomil gold and Sunvit gave an average of 70.28 and 47.23% decrease in white rust severity (PDI),  110.50 and 97.91% increase in red amaranth yield and 27.42 and 7.26% increase in 1000-seed weight. Other fungicides gave 8.18-40.52 decrease in PDI, 22.31-62.85 increase in red amaranth yield and 8.06-12.90% increase in 1000-seed weight. Among six fungicides tested, the most effective fungicide to control white rust and to increase yield of red amaranth was Ridomil gold followed by Sunvit. Other investigators also effectiveness of fungicides to control white rust of amaranth (Verma and Petrie 1979). Based on this results Ridomil Gold 68 WP @ 0.2% foliar spray may be recommended to control white rust of red amaranth.

LITERATURE CITED

Anonymous. 1984. Crop disease survey and establishment of a herbarium at BARI. Second annual progress report, Plant Pathology Division, BARI, Joydebpur, Gazipur. p48

Gomez, K. A. and Gomez, A. A. 1983. Statistical procedures for agricultural research, Second edition, IRRI, Manila, Philippine. pp. 139-207.

Kolte, S. J. 1985. Diseases of annual adible oilseed crops. Volum II: Rapeseed-mustard and sesame diseases. Boca Raton, FL: CRC Press, Inc.

Mehta, P. P. and Mondol, K. K. 1978. Field screening of groundnut cultivars against rust of tikka. Indian Phytophathol. 31:259-260

Nyvall, R. F. 1989. Field crop diseases handbook. New York: Van Nostr and Reinhold. pp. 351–64.

Talukder, M.J.1974. Plant disease of Bangladesh. J. Agric. Res. 1:61-86.

Verma, P. R. and Petrie, G. A. 1979. Effect of fungicides on germination of Albugo candida oospores in vitro and on the foliar phase of white rust disease. Canadian Pl. Dis. Sur. 59:53–59.

Zaman, S. H., Rahim, H. K. and Hawlader, M. 1982. Simple lesson for biometry. Bangladesh Rice Research Institute, Joydebpur, Gazipur-1701, Bangladesh. p.171.

Did you find apk for android? You can find new Free Android Games and apps.


1Regional Horticultural Research Station, Bangladesh Agricultural Research Institute (BARI), Lebukhali, Patuakhali; 2
Regional Agricultural Research Station, BARI, Rahmatpur, Barisal, Bangladesh

LEAVE A REPLY


Related Papers: