International Journal of Chemical Studies 2017; 5(5): 1210-1212 P-ISSN: 2349–8528 E-ISSN: 2321–4902 IJCS 2017; 5(5): 1210-2121 © 2017 IJCS Received: 06-07-2017 Accepted: 11-08-2017 Ganesha Naik R Dept. of Plant Pathology, University of Agricultural and Horticultural Sciences, Shivamogga, Karnataka, India Jayalakshmi K Dept. of Plant Pathology, University of Agricultural and Horticultural Sciences, Shivamogga, Karnataka, India Evaluation of fungicides against leaf spot of bhendi incited by Cercospora abelmoschi under field conditions Ganesha Naik R and Jayalakshmi K Abstract Among eight fungicides evaluated against Cercospora leaf spot disease of bhendi under field conditions, Propiconazole 25 EC (0.1%) was found significantly superior in controlling the disease. The percent disease index (PDI) was significantly less (11.79) in Propiconazole 25 EC sprayed plot followed by Carbandizim 12% + Mancozeb 63% WP (16.31) and Cymoxanil 8% + Mancozeb 63% WP (19.28) compared to other fungicides and unsprayed control plot (87.85 PDI) respectively. Correspondingly, a maximum fruit yield of 16844.44 kg/ha was recorded in plot in which Propiconazole 25 EC was received followed by Carbandizim 12% + Mancozeb 63% WP (15,888.89 kg/ha) and Cymoxanil 8% + Mancozeb 63% WP (15,500.00 kg/ha) sprayed plots respectively. Whereas, in unsprayed control plot a minimum fruit yield of 11,022.22 kg/ha was recorded. The B:C ratio was also found higher in propiconazole 25EC (1:3.09) Carbandazim 12% + Mancozeb 63% (1:2.58) and Cymoxinil 8% + Mancozeb 63% WP (1:2.37) sprayed plots compare to other fungicides and untreated control plots. Keywords: Bhendi, Cercospora abelmoschi, fungicides, B: C ratio Introduction Bhendi (Abelmoschusesculentus L. Moench) is one of the most important vegetable crop extensively cultivated in kharif and rabi seasons in India. It belongs to the family Malvaceae. It is known by many local names in different parts of the world and it is called "lady's finger" in England, "Gumbo" in United States and "Bhendi" in India (Chauhan, 1972) [9]. Bhendi is known to be originated from West Africa (Joshi et al., 1974) [12]. It is an annual vegetable crop grown from seed in tropical and sub tropical parts of the world. It is rich in vitamins, calcium, potassium and other mineral nutrients. Bhendi is found to suffer from a number of diseases caused by fungi, bacteria, viruses, phytoplasm and nematodes. The most important diseases of okra are Damping Off Fusarium Wilt, Powdery Mildew, Yellow Vein Mosaic Virus (YVMV) and Leaf Spot. Among the fungal diseases Cercospora leaf spot of bhendi incited by Cercospora is one of the most economically important in all regions wherever bhendi is grown. In India, two species of Cercospora produce leaf spots on bhendi. C. malayensis causes brown, irregular spots and C. abelmoschi causes sooty black, angular spots. Both the leaf spots cause severe defoliation and are common during humid seasons. Dhancholia and Singh (1992) [10] reported severe infection by C. abelmoschi on bhendi. Nowadays, this disease incited by C. abelmoschi becomes more severe in southern transition zone of Karnataka. Initially the disease symptoms observed on the lower surface of the leaves as indistinct spots in th form of olivaceous specks. Later on light brown to grey mouldy growth of the fungus covered the entire lower surface. As disease advanced, necrotic spots were also observed on the upper surface of leaves. The infected leaves ultimately dry and defoliate. The disease progress upward from lover leaves and infects stem and fruits and produces similar symptoms. Keeping this in view, efforts have been made to find out the efficacy of various fungicides on the management of Cercospora in bhendi. Correspondence Ganesha Naik R Dept. of Plant Pathology, University of Agricultural and Horticultural Sciences, Shivamogga, Karnataka, India Material and Methods During kharif 2016 a field experiment was carried at Agricultural and Horticultural Research station Bhavikere, Chikaagaluru district of Karnataka. The experiment was laid out in RBD design with three replications and there were nine treatments. Highly susceptible bhendi cultivar Mahyco-10 for Cercospora leaf spot was sown in a plot size of 3m x 3m with ~ 1210 ~ International Journal of Chemical Studies recommended package of practices. Various fungicides viz., Carbendazim 50WP, Carbendazim 12% + Mancozeb 63% WP, Propiconazole 25EC, Thiophenate methyl 75WP, Iprobenphos 48EC, Chlorothalonil 75WP, Mancozeb 75 WP and Cymoxanil 8% + Mancozeb 63% WP were sprayed twice at 8 days interval starting from the initiation of the disease. Ten days after the second spray, five plants from each plot were selected and observations were recorded. The severity of the disease was assessed based on 1-5 scale and PDI has been calculated as per Wheeler formula, 1969. Finally the fruit yield were recorded from each treatment and analysed statistically. The cost: benefit ratio was worked out based on the cost of fungicides, spray cost, yield and the market value of bhendi during 2016. Results and Discussion During 2014, the percent disease index was to the tune of 88 percent. Proportionately different fungicides controlled the disease effectively. Among the different fungicides, the percent disease index was significantly less (11.79PDI) in propiconazole sprayed plots followed by Carbendizim + mancozeb (16.31 PDI) and Cymoxanil + Mancozeb (19.28 PDI). as compared to other treatments and unsprayed control plot (87.85 PDI). The maximum yield and B: C ratio (16844.44kg/ha and 1:3.09) was recorded in plots that received propiconazole spray followed by the Carbendizim + Mancozeb (15888.89kg/ha with 1:2.58 B: C ratio) and Cymoxanil + Mancozeb (155000.00 kg/ha with 1:2.37 B: C ratio). Whereas, minimum fruit yield of 11022.22 kg/ha was recorded in untreated control plot with maximum PDI of 87.85 (Table 1). All these findings are in accordance with other researchers viz., Ghosh et al., (2003) [11], Amenduini et al., (2003) [1], Khaleaquzzaman et al., (2003), Atia and Tohamy (2004) [5], Ayoub and Qureshi (2004) [6], Surviliene et al., (2006) [16], Antonijevic et al., (2007) [3] and Bulajic et al., (2007) [8] showed propiconazole is effective to control the Cercospora leaf spot disease. Fungicides like Propiconazole, Tebuconazole and Bavistin were registerd for use on bhendi would also effectively control Cercospora leaf spot (Ansari et al., 1992; Srivastava et al., 1992; Beura et al., 2007 and Arain et al., 2012) [2, 15, 7, 4]. The cost effectiveness of the systemic fungicides in bhendi against Cercospora leaf spot was studied and it was found that application of Propiconazole followed by Carbendizim + Mancozeb was more remunerative. Several previous reports enlights that fungicides application increases the yield of bhendi. In the present study, the fungicide Propiconazole 25EC (0.1%) found superior in reducing the Cercospora leaf spot disease incidence and thus helped for getting highest fruit yield and B:C ratio. Table 1: Effect of various treatments on the incidence of Cercospora leaf spot disease of Bhendi and yield Treatments Conc.(%) Percent Disease Index (PDI) Yield (Kg/ha) B:C ratio Carbendazim 12% + 0.2 16.31 15888.89 1:2.58 Mancozeb 63%WP Propiconazole 25EC 0.1 11.79 16844.44 1:3.09 Thiophenate methyl 75WP 0.1 23.84 14711.11 1:1.94 Iprobenphos 48EC 0.1 26.34 13544.44 1:1.36 Chlorathalonil 75WP 0.15 27.06 13655.55 1:1.39 Mancozeb 75WP 0.25 27.95 13777.78 1:1.49 Cymoxinil 8% + 0.2 19.28 15500.00 1:2.37 Mancozeb 63% WP Untreated control 87.85 11022.22 SEm ± 0.93 618.84 C.D@5% 2.78 1855.29 C.V(%) 5.52 7.46 - References 1. Amenduini M, M D'Amico, C Colella, M Cirulli. Severe outbreaks of Alternaria leaf spot on kiwi in Southern Italy. Ferguson-Basilicata. 2003; 53(11):39-43. 2. Ansari MM, Mandal AB, Ram T. Chemical control of leaf-spot of okra caused by Cercospora abelmoschi. J. Andaman Sci. Asso. 1992; 8(1-2):94-96. 3. Antonijevic D, P Fakultet, B Zemun, P Mitrovic. Leaf spot of oilseed rape Biljni lekar (Serbia). Plant Doctor. 2007; 35(4):443-449. 4. Arain AR, Jiskani MM, Wagan KH, Khuhro SN, Khaskheli MI. Incidence and chemical control of okra leaf spot disease. Pak. J. Bot. 2012; 44(5):1769-1774. 5. Atia MMM, MRA Tohamy. First Record of Alternaria leaf spot disease on okra in Egypt. Egypt. J Phytopathol. 2004; 32(1-2):139-140. 6. Ayoub M, AA Qureshi. Chemical control of brown leaf spot disease of tobacco (D.V. Cigarette) by Alternaria longipes. Pak Tobacco, 2004, 15-17. 7. Beura SK, Mohapatra KB, Paul PK, Nandi A. Chemical management of Cercospora blight of okra in Orissa. J. Pl. Prote. and Envir. 2007; 4(2):134-137. 8. 9. 10. 11. 12. 13. 14. ~ 1211 ~ Bulajic AR, Poljoprivredni Fakultet, B Zemun. Leaf spot and early blight caused by Alternaria solani. Savremeni povrtar (Serbia). 2007; 6(24):42-45. Chauhan DVS. Vegetable production in India (3rd Edn.) Ram Prasad & Sons, Agra (U.P.) India. 1972, 368. Dhancholia S, Singh D. Cercopsora blight E II. and EV. Okra in Himachal Pradesh. Himachal J. Agril. Res. 1992; 18(1-2):60. Ghosh C, NB Pawar, CR Kshirsagar, AC Jadhav. Studies on management of leaf spot caused by Alternaria alternata on Gerbera. J. Maharashtra. 2003; 27(2):165167. Joshi AB, Gadwal VR, Hardas MW. Evolutionary studies in world crops, diversity and change in the Indian subcontinent, (ed. J.B. Hutchinson). Combridge, 1974, 99-10. Khalequzzaman KM, MK Hossain, MS Islam, MH Rashid. Yearly incidence and effect of fungicides in controlling leaf spot of Sapota. Asian J. of Pl.t Sci. 2003; 2(5): 442-444. Shrawan Kumar, Dabbas MR, Priti Tiwari. Evaluation chemicals against cercospora leaf spot of okra. Intl. J. Plt Protec. 8(2):384-388. International Journal of Chemical Studies 15. Srivastava LS, Gupta DK, Verma RN. Chemical control of Cercospora blight of okra Sikkim IJ, Myco. & Pl. Path. 1992; 22(1):73-74. 16. Surviliene E, A Valiuskaite, L Raudonis. Effect of fungicides on Alternaria diseases of carrot. Pl. Protec. 2006; 30(1):319-321. ~ 1212 ~