Pak. J. Phytopathol., Vol. 26 (02) 2014. 187-191 Official publication of Pakistan Phytopathological Society Pakistan Journal of Phytopathology ISSN: 1019-763X (Print), 2305-0284 (Online) http://www.pakps.com EFFICACY OF DIFFERENT PROTECTIVE FUNGICIDES AGAINST CERCOSPORA LEAF SPOT OF MUNGBEAN (VIGNA RADIATA L. WILCZEK) aMuhammad U. Shahbaz*, aMuhammad A. Iqbal, aMuhammad Rafiq, aAasia Batool, bMuhammad Kamran a Pulses Research Institute, AARI, Faisalabad (Punjab) Pakistan. b Department of Plant Pathology, University of Agriculture, Faisalabad, Pakistan ABSTRACT The experiment was planned to minimize the losses in mungbean against Cercospora leaf spot disease caused by Cercospora canescens Ellis & Martin. For this purpose a mungbean susceptible line was sown in three sets with three replications and four treatments i.e. Propineb (Antracol), Metalaxl+Mancozeb (Ridomil Gold), Mancozeb and Water as control. After fungicides spray artificial inoculation of C. canescens was given to three sets with 5 days interval to create disease epidemic. Results showed that all the protective fungicides reduced the incidence and severity percentages of Cercospora leaf spot. In particular Ridomil Gold and Antracol shown better results but Ridomil Gold was the best among all which substantially reduces the number of infected leaves and lesions on foliage and pods. It was also found that Ridomil Gold gave best results where it was sprayed within 10 days of infection (on Set I). It managed disease at 18.51% disease index which was much less than the untreated block where disease index was 40.74%. Keywords: Chemicals, management, plant diseases. INTRODUCTION Legume crops are the cheapest source of protein and also called poor men’s protein Mian, 19 . )n legumes, mungbean is an important crop of South and Southeast Asia. Recently mungbean was grown on 136,100 ha and production was 89,300 ton in Pakistan which is less than the previous year (Anonymous, 2013). Mungbean has sown as a monocrop in different cropping systems which popular due to its early maturity and association with nitrogen fixing bacteria (Chankaew et al., 2011). Genus Cercospora is parasitic on many crops, herbaceous, ornamental plants and trees throughout the world. CLS is an important disease of mungbean crop caused by a biotrophic fungus C. canescens. Due to this disease yield losses up to 50-70% has been observed (Lal et al., 2001 and Chand et al., 2012). CLS can cause heavy defoliation in severe conditions on mungbean especially at optimum temperature 25-30oC with RH 90100%. Symptoms of this disease appear mainly on leaves but also on stem, branches and pods. The disease * Corresponding Author: Email: umar739@yahoo.com © 2014 Pak. J. Phytopathol. All rights reserved. 187 appears initially on the lower leaves of the infected plants and then spread all over the plant. It also reduces the number and size of pods and seeds (Grewal et al., 1980). Hossain et al 2011 described that the disease was mainly observed when crop was at flowering, pod formation and ripening stage. CLS disease mainly managed by tillage operations, crop rotations, host plant resistance and fungicides (Hanson and Panella, 2003; Khan and Smith, 2005; Khan, 2008). This disease was managed mainly through fungicides (Singh and Naik, 1977; Singh and Singh, 1978). In the mungbean growing areas CLS had serious threat while high humidity prevails during crop season (Bashir and Zubair, 1985). This has not been thoroughly investigated disease for mungbean in Pakistan but its impact on crop yield and seed quality at maturity is alarming. The objectives of this study are to evaluate different protective fungicides for mungbean against Cercospora leaf spot. MATERIAL AND METHODS Planting Conditions: The experiment was conducted in the Kharif, 2013 (July - September) season at the Pulses Research Institute, Faisalabad, Pakistan, on fertile soil. Pak. J. Phytopathol., Vol. 26 (02) 2014. 187-191 at 25 oC for 10-14 days (Fig. 2). The inoculum was The high humidity and dry period in this cropping sprayed on set I after 5 days of the protective fungicides, season in Pakistan favors the development of this on set II after 10 days and on set III after 15 days. The disease in the region. concentration of inoculum was adjusted at 5×105 Planting material: The mungbean line C2-94-4-36 was conidia/ml by using haemocytometer. selected for this experiment due to its susceptibility to Disease observations: The disease incidence and CLS disease. The same line was used as control in the severity were recorded after one week of each inoculum trial on which distilled sterilized water was sprayed. spray on three sets. The incidence/ infection percentage Experiment design: The experiment was sown in (IP) was calculated as follows; Randomized Complete Block Design (RCBD) in three sets. Each set consists of three replications and each replication comprises of four blocks of treatments. Each The disease severity was calculated by using the 0-9 block of 1×4 m with 30 cm row and 10 cm plant to plant scale (Table 1) and Percentage Disease Index (PDI) was distance. The sowing was done with dibblers in the first calculated by following; week of July, 2013 (Fig. 1). Antifungal treatments: The application of protective fungicides was performed after 50 days of sowing before the appearance of the disease. All the treatments were Data analysis: The evaluation of the disease in each set sprayed on the three sets. The distilled sterilized water was and treatment was estimated by infection percentage sprayed as control (T0) and the other three fungicides were and percentage disease index. Data was analyzed by Antrocol (Dose: 2.47 kg/ha; T1), Ridomil Gold (Dose: using Statistix and SPSS computer programmes for 618g/ha; T2) and Mancozeb (Dose: 1.2 Kg/ha; T3). analysis of variance. The least significant difference was Preparation of inoculum: Inoculum was prepared from calculated for comparing the means of treatments of the old growing culture of C. canescens, multiplied on three sets at 5% level of probability. sterilized/ autoclaved mungbean grains and incubated Table 1. Disease severity rating of CLS Severity Rating Symptoms on plants at flowering and pod formation stage 0 No visible symptoms on plants 1 1-10% foliage or pod area affected with small pinhead lesions 3 11-20% foliage or pod area affected with small round brown spots 5 21-30% foliage or pod area affected with large spots 7 31-50% foliage or pod area affected with bigger coalescing spots 9 51-100% foliage or pod area affected with bigger coalescing spots Figure 1. CLS affected trial. 188 Pak. J. Phytopathol., Vol. 26 (02) 2014. 187-191 Figure 2. Mass multiplication of C. canescens on Mungbean seeds. RESULTS distilled sterilized water was sprayed and lowest was on The data obtained after the evaluation of different Ridomil Gold (81.17%) after that Antracol (84.01%) and protective fungicides revealed a gradual increase in both Mincozeb (82.76%) respectively. The highest PDI was incidence and severity percentage with the increase of observed in control (40.74%) then Mancozeb (25.92%) inoculation days in three sets. In set I (5 DAI) the highest in set I. Radiomil Gold (18.51%) and Antracol (18.52%) IP was recorded in control (85.15%) on which simply showed same trend in set I regarding PDI (Fig. 3 and 4). Set II (10 DAI) results shown variable response against CLS. The lowest PDI was shown by Ridomil Gold (18.56%) and highest was found in control (62.97%). Antracol and Mincozeb managed PDI at 25.92% and 40.74 %. The lowest IP 87.27% was present in Ridomil Gold among the four treatments in Set II. The incidence of Antrocol and Mancozeb were 90.60% and 91.00% 189 respectively. The Ridomil Gold and Antracol showed the same trend in set III (15 DAI) as they show in set I but the PDI value was 33.33%. The PDI of control and Mancozeb were 70.37% and 48.15% respectively. Ridomil Gold showed the lowest incidence 83.12% in Set III while Antracol and Mancozeb shown 95.68% and 92.99% respectively (Fig. 3 and 4). Pak. J. Phytopathol., Vol. 26 (02) 2014. 187-191 In set I the incidence/ infection percentage (IP) was 83.28% while in set II and III CLS incidence was 90.62% and 92.26% respectively. The percentage disease index (PDI) in three sets was 25.92%, 37.04% and 46.30% respectively. Over all the best results was given by Radiomil Gold among the treatments. Radiomil Gold managed CLS incidence and severity at 83.85% (IP) and 23.45% (PDI) respectively which is much less than the other treatments. Antracol control CLS incidence and severity at 90.10% and 25.92%. CLS incidence and severity were 88.91% and 38.21% where Mancozeb was applied (Table 2). Table 2. Over all comparison of treatments and three sets. Treatments Infection Percentage Percentage Disease Index Antracol 90.101 A 25.923 C Ridomil Gold 83.857 B 23.454 C Mancozeb 88.919 AB 38.271 B Control 91.996 A 58.027 A C.V 6.56 26.35 Sig. 0.0377 0.0000 Days After Inoculation (3 Sets) 05 DAI (Set I) 83.278 B 25.924 C 10 DAI (Set II) 90.620 A 37.037 B 15 DAI (Set III) 92.257 A 46.296 A CV 6.56 26.35 Sig. 0.0017 0.0001 Different letters in the same column show significant difference at 0.05 probability level. 190 DISCUSSION CLS is the most important and alarming disease which seriously reduce mungbean production in Pakistan. This disease occurs in all the mungbean growing areas of Pakistan at crop maturity stage that reduces the pod formation and seed setting which ultimately cause the yield losses. As mungbean is poor men’s protein Mian, 1976) which contains 26% protein, 51% carbohydrates, 10% moisture, 4% minerals and 3% vitamins (Khan, 1981). Pakistan is a developing country and pulses are the cheapest source of protein in this country but mungbean production is decreasing from previous years (93,000 ton in 2012; 89,300 ton in 2013) (Anonymous, 2013). Also the average yield of mungbean is decreasing as compared to its yield potential of 2-4 ton/ha (Ramakrishna et al., 2000). There are many factors which are responsible for its low yield among which disease infestation is the most important. Different approaches were carried out to manage CLS such as spray of fungicides and plant extracts and use of resistant varieties. Due to lack of commercialization of plant extracts and its awareness to the formers, fungicides are the immediate and good source of CLS management. Also there is no resistant variety in the country which is resistant to CLS at maturity stage. So, the efficacy of different protective fungicides was evaluated in this study to combat with CLS. CONCLUSION The study revealed that the tested fungicides decreased PDI and IP of CLS in mungbean. Conclusion was made that Radomil Gold gave better results as compared to other treatments. It is recommended that one spray of Pak. J. Phytopathol., Vol. 26 (02) 2014. 187-191 Ridomil Gold (618 g/ha) at the time of just appearance of CLS can save crop from severe losses. If dry wet weather prolongs the 2nd spray after 7 days of first spray is also necessary. This will decrease CLS disease incidence to a better extent. ACKNOWLEDGEMENTS The authors acknowledge the breeders of Pulses Research Institute AARI, Faisalabad Pakistan for their support and cooperation. REFERENCE Anonymous. 2013. Pakistan Economic Survey. Pakistan Bureau of Statistics. pp. 23. Bashir, M. and M. Zubair. 1985. Survey Report of Kharif Pulses in Islamabad, Rawalpindi and Sialkot Districts during 1985. Pulses Programme, Tech. Report. Nat. Agric. Res. Centre, Islamabad. Chankaew, S., P. Somta, W. Sorajjapinun and P. Srinives. 2011. Quantitative trait loci mapping of Cercospora leaf spot resistance in mungbean, Vigna radiate (L.) Wilczek. Mol. Breed. 28: 255264. Chand, R. V. Singh, C. Pal, P. Kumar and M. Kumar. 2012. First report of a new pathogenic variant of Cercospora canescens on mungbean (Vigna radiata) from India. New Disease Reports 26: p. 6. Grewal, J.S., P. Machendra and D.P. Kulshrestha, 1980. Control of Cercospora leaf spot of green gram by spraying Bavistin. Indian J. Agric. Sci. 50: 707-11. Hanson, L. E. and L. Panella. 2003. Disease control in sugar beet. Int. Sugar. J. 105: 60-68. Hossain A.M.M.Z., D.D. Chatterjee, B. Howlader, K. Kanti and Jalauddin. 2011. Incidence and severities of 191 Cercospora leaf spot on different strain of growing mungbean. Bangladesh Res. Pub. J. 5: 1-6. Khan, M.R.I. 1981. Nutritional quality characters in pulses. Proceedings of National workshop on pulses, BARI, Gazipur. p. 199-206. Khan, M.F. 2008. Evaluating strategies for managing Cercospora leaf spot of sugarbeet (abstract). Phytopathol. 98: p. 80. Khan, M.F.R. and L.J. Smith. 2005. Evaluating fungicides for controlling Cercospora leaf spot on sugar beet. Crop Prot. 24: 79-86. Lal, G., D. Kim, S. Shanmugasundaram, and T. Kalb. 2001. Mungbean production by AVRDC. World Vegetable Center, Taiwan, Shanhua: AVRDC-The World Vegetable Center p. 6. Mian, A.L. 1976. Grow more pulse to keep your pulse well. An Essay of Bangladesh Pulse, Dept. of Agron., BAU, Mymensingh. pp. 11-15. Ramakrishna, A., C.L.L. Gowda and Johansen. 2000. Management factors affecting legumes production in the Indo-Gangetic plain. In: Legumes in Rice and Wheat Cropping Systems of the Indo-Gangetic Plain- Constrains and Opportunities. ICRISAT, Patancheru, Andrapradesh, India. pp. 156-165. Singh, S.D. and S.M.P. Naik. 1977. Field control of Cercospora leaf spot of urdbean by fungicides. Indian J. Mycol. Pl. Pathol. 6: 99. Singh, D.V. and R.R. Singh. 1978. Field evaluation of fungicides for the control of Cercospora leaf spot of green gram. Pesticides 12: 28-9.