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Frog eye leaf spot disease of FCV tobacco caused by Cercospora nicotianae in Southern Districts of Karnataka.

Tobacco (Nicotiana tabacum L.) belongs to the family Solanaceae, is believed to be introduced into India from its native Central America by Portuguese in 1603. It is a major commercial crop of India, grown throughout the country. India is one of the principal tobacco producing countries of the world and has attained its commercial importance in India. Successful cultivation of tobacco in recent years has met with different problems such jas pests and diseases. Among the various fungal diseases, Cercospora leaf spot is one of the most serious diseases of tobacco which reduces leaf quality and alkaloid centents to a greater extent. . The frog eye leaf spot disease of tobacco caused by Cercospora nicotianae has been reported for the first time in India by Vasudeva in 1963 from Patansagar (M.P).In the present investigation various aspects on Frog eye lreaf spot of tobacco (Nicotiana tabacum L.) was undertaken during the period 2014 to 2015 with reference to survey and surveillance of disease, In vitro and In vivo management of disease by fungicides.

MATERIALS AND METHODS

Survey and surveillance on incidence of frog eye leaf spot disease of FCV tobacco in Sorthern Karnataka

A roving survey was conducted to know the per cent incidence of frog eye leaf spot disease in FCV tobacco growing areas of Shivamogga, Davanagere and Chikkamagalur districts during 2014-15. Survey was taken up for four months starting from June to September. In each taluka's three villages were selected and three fields in each village were considered for survey. In each location five tobacco plants were randomly scored using the following formula other worker (6).

PDI = [Sum of numerical ratings/Total number of leaves examined x Maximum grade value] x 100

In vitro evaluation of different fungicides against C. nicotianae

The efficacy of five systemic and four non-systemic and four combi-products fungicides were tested against C. nicotianae for radial growth inhibition on the potato dextrose agar media using poisoned food technique under in vitro condition viz., Hexaconazole, Propiconazole, Tricyclazole, Thiophanate methyl, Carbendazim, Mancozeb, Chlorothalonil, Captan, Zineb, Hexaconazole 4% +Zineb 68% WP (Avatar), Tricyclazole 4% +Mancozeb 62 % WP(Merger), Tebuconazole 50% + Trifloxystrobin 25% (Nativo G), Carbendazim 12% + Mancozeb-63% (Companion) were assyed.The non-systemic fungicides and combi product were tried at 125, 250, 500 and 1000 ppm concentration, whereas systemic fungicides were tried at 100, 200, 400 and 600 ppm concentrations. The study was conducted at Plant Pathology Department, UAHS, Shivamogga during 2013-14.The quantity of fungicides was calculated for 100 ml medium separately. The requisite quantity of fungicides was added to each flask at 45 [degrees]C the fungicides were thoroughly mixed before solidification and poured into sterilized petri plates. The mycelia disc of 5mm diameter of nine days old culture was cut with the help of sterile cork borer. Each disc was transefered aseptically to the centre of each petri plate, already poured with poisoned medium. The PDA plates without fungicides were also inoculated and maintained as control. The plates were incubated at room temperature (27 [+ or -]1[degrees]C) for 12 days. Five replications per treatment were maintained. The observations on colony growth recorded until petriplate in control treatment was fully covered with mycelia growth and calculated percent inhibition by using the formula (5).

Evaluation of different fungicides against C. nicotianae

A field experiment were carried out at the Zonal Agriculture and Horticultural Research Station (ZAHRS) Navile, Shivamogga, University of Agricultural and horticultural Sciences, Shivamogga, Karnataka. The efficacy of four systemic and two non-systemic fungicides was evaluated. The experiment was conducted in randomized block design with seven treatments and three replications with cultivar KST-19. The details of the treatments are given here under.
S. No    Treatment details      Concentration   Trade names
                                 (per cent)

T1       Hexaconazole 5% EC          0.1           Contaf

T2       Propiconazole 25% EC        0.1            Tilt

T3       Carbendazim-12% +           0.2         Companion
         Mancozeb-63%

T4       Tebuconazole 50% +         0.05          Nativo G
         Trifloxystrobin 25%

T5       Mancozeb 75WP               0.2        Dithane M-45

T6       Carbendazim                 0.1          Bavistin

T7       Control


Plot size of 3.4 x 2.8 m was maintained per treatment. The transplanting of tobacco was taken up on 29.03.2014. First spray was taken up immediately after disease appearance followed by another two spray at 10-12 days interval.

RESULTS AND DISCUSSION

Survey and surveillance on incidence of frog eye leaf spot disease of FCV tobacco in Sorthern Karnataka

Results of the survey revealed that, leaves were more vulnerable to the attack by Cercospora nicotianae more disease severity on leaves, irrespective of season, location and variety. The data presented in (Table 1) revealed that among three districts surveyed, maximum percent disease index was recorded in Chikamagaluru (28 %) followed by Davanagere (24 %) district, However the least severity was recorded in Shivamogga (14.66 %) district. Taluk wise severity of frog eye leaf spot of tobacco surveyed during 2014-15 exhibited that maximum disease severity of 28 PDI was recorded in Tarikere taluk followed by Honnali (24 PDI) and Shivamogga (16 PDI). Least disease severity of 14.66 PDI was found in Shikaripura taluk. The present findings are also in conformity with the worker (2), who reported that the September and October months are favourable period for frog eye leaf spot, recording a mean incidence of 13.05 per cent and 12.06 per cent irrespective of locations respectively. The villages Akkol and Aadi are considered as most severe zone and hot spots for frog eye leaf spot in Nipani. Avoidable loss due to this disease has been estimated to the tune of 21 per cent in bidi tobacco field under normal monsoon conditions in Gujarath (3).

In vitro evaluation of different fungicides against C. nicotianae

Five systemic, four non-systemic fungicides and four combi-products fungicides were screened against C. nicotianae by poison food technique. The data presented in (Table 2a, 2b and 2C) revealed that fungicides were found significantly superior in reducing the growth of fungus. Among non-systemic (four combi) fungicides, captan and Tebuconazole 50% + Trifloxystrobin 25% (Nativo G) at 125 ppm concentration showed 72.96 and 91.04 per cent inhibition of mycelial growth of fungus followed by Carbendazim-12% + Mancozeb-63% (Companion) with 76.63 per cent and least inhibition of mycelial growth was recorded in Zineb (37.48 per cent) with 125 ppm concentration. Systemic fungicides, Hexaconazole showed 100 per cent inhibition of mycelialll growth of fungus and was followed by carbendazim (69.46%) at 100 ppm concentration while, least per cent inhibition of mycelial growth was recorded in trycyclazole (30.92). The effectiveness of the triazole fungicides like propiconazole may be attributed to their interfeance with the biosynthesis of fungal sterols and inhibit the ergosterol biosynthesis. These results are conformity with findings of other workers (2,4) showed Hexaconazole, carbendazim and propiconazole inhibited mycelial growth of C.nicotianae.

Evaluation of different fungicides against C. nicotianae

The results after two sprays revealed that, lowest disease severity of 26.00 PDI was observed in carbendazim 0.1 per cent which was significantly superior over other treatments followed by hexaconazole and propiconazole with a PDI of 29.15 and 31.75 at 0.1 per cent. The other fungicides viz., Carbendazim-12%+Mancozeb-63% (0.2 %), Tebuconazole 50% + Trifloxystrobin 25% (0.05%) and Mancozeb 75WP (0.2%) were found less effective (Table 3). Maximum disease severity i.e., 67.25 PDI was recorded in untreated control. Finally concluded as carbendazim at 0.1 per cent concentration was significantly superior over other fungicides, where as hexaconazole and propiconazole at 0.1 per cent remained statistically on par with each other. The similar results were reported other worker (1) identified that the Carbendazim, Propiconazole and Hexaconazole were highly effevtive against frog-eye leaf spot of bidi tobacco in Karnataka. Among non-systemic and combi fungicides, combi product like Tebuconazole 50% + Trifloxystrobin 25% (Nativo) at 0.05 percent concentration was significantly superior where as Companion at 0.2% and mancozeb were less effective. The results are in agreement with other worker2.

REFERENCES

(1.) Hundekar, A.R. and Shamarao Jahagirdar., Management strategies against frog eye leaf spot pathogen (Cercospora nicotianae) in India. Indian Phytopath. 2010; 63(1): pp. 63-65.

(2.) MALLAPPA., Studies on frog eye leaf spot of bidi tobacco caused by C. nicotianae Ell. & Eve. M. Sc. (Agri) Thesis, Univ. Agric. Sci., Dharwad (India), 2007.

(3.) Patel, B. N., Patel. H. R., Patel, P M., Bhatt, N. A., Patel, K. D., Patel, J. G. and Patel, S. J., Assessment of avoidable yield loss due to frog eye disease in bidi tobacco. Tob. Res., 2001; 27(2): 187-189.

(4.) Veena, Investigation on leaf spot of greengram caused by Cercospora canescens Ellis and Martin. M. Sc. (Agri.) Theses, Univ. Agric. Sci., Dharwad (India), 2012; 69.

(5.) Vincent, J. M., Distortion of fungal hyphae in the presence of certain inhibitors. Nature, 1947; 159: 850.

(6.) Wheeler, B. E. J., An introduction to plant diseases. Jhon Wiley and Sons Ltd.,London, 1969.

N.D. Punit Kumar [1], C. Karegowda [1], R. Murali [1], B.R. Sayiprathap [1], M. Mahesh [2], H. Nagaraj [1], J. Raju [1], K. Jayalakshmi [1], K.B. Rudrappa [3], T.G. Manu [1], T.H. Kavitha [1] and S.B. Mahantesh [1]

[1] Department of Plant Pathology, College of Agriculture, University of Agricultural and Horticultural Sciences, Shivamogga-577 204, Karnataka, India.

[2] Department of Plant Pathology, College of Agriculture, Bimarayanagudi, University of Agricultural Sciences, Raichuru, Karnataka, India.

[3] Department of Plant Pathology, College of Agriculture, Bangalore, University of Agricultural Sciences, Bangalore, Karnataka, India.

(Received: 17 November 2015; accepted: 03 January 2016)

* To whom all correspondence should be addressed. E-mail: pndagri09@gmail.com
Table 1. Survey and surveillance on incidence of frog eye
leaf spot disease of FCV tobacco in Sorthern Karnataka

S.     District       Taluk         Village          PDI
No.

1      Davanagere     Honnali       Chattanahally    24.00
                                    Jeenahally       20.00
                                    Palavanahally    28.00
                                    Mean             24.00
2      Chikmagaluru   Tarikere      Belenahalli      32.00
                                    Nandhi           28.00
                                    Nandihosahally   24.00
                                    Mean             28.00
3      Shivamogga     Shivamogga    Byranakoppa      20.00
                                    Kallagangur      16.00
                                    mallapura        12.00
                                    Mean             16.00
                      Shikaripura   Jakkinakoppa     24.00
                                    Oldjoga          12.00
                                    Beeranahally     08.00
                                    Mean             14.66

* Per cent disease index

Table 2(a). In-vitro evaluation of systemic fungicides
against C nicotianae

                                       (%) Inhibition over
                                              control
                                       Concentration (ppm)

S.     Fungicides           Trade      100         200
No                          name

1      Hexaconazole 5%      Contaf     100         100
       EC                              (90.00) *   (90.00)

2      Propiconazole 25%    Tilt       26.01       100
       EC                              (26.01)     (90.00)

3      Tricyclazole 75 %    Beam       30.92       31.54
       WP                              (34.13)     (33.88)

4      Thiophanate methyl   Roko       66.92       67.69
       70 % WP                         (54.70)     (55.68)

5      Carbendazim 50 %     Bavistin   69.46       100
       WP                              (69.46)     (90.00)

6      Control                         90.00       90.00
                                       (0.0)       (0.0)

       Mean                            58.78       79.72
                                       (46.01)     (67.45)

                            (%) Inhibition over
                                   control        Mean
                            Concentration (ppm)

S.     Fungicides           400        600
No

1      Hexaconazole 5%      100        100        100
       EC                   (90.00)    (90.00)    (90.00)

2      Propiconazole 25%    100        100        81.50
       EC                   (90.00)    (90.00)    (74.00)

3      Tricyclazole 75 %    35.38      43.08      35.23
       WP                   (36.26)    (41.02)    (36.32)

4      Thiophanate methyl   69.85      72.31      69.19
       70 % WP              (56.82)    (58.25)    (56.36)

5      Carbendazim 50 %     100        100        92.36
       WP                   (90.00)    (90.00)    (84.87)

6      Control              90.00      90.00      90.00
                            (0.0)      (0.0)      (0.0)

       Mean                 81.04      83.07      75.65
                            (68.27)    (69.82)    (62.89)

* Figures in parentheses are angular transformations

                     S.Em       CD @ 1 %
                     [+ or -]

Fungicide (F)        0.07       0.27
Concentration (c)    0.06       0.24
F x C                0.14       0.55

Table 2(b). In-vitro evaluation of Non-systemic
fungicides against C.nicotinae

                                        (%) Inhibition over
                                             control
                                        Concentration (ppm)

S.      Fungicides       Trade          100          200
No                       name

1       Mancozeb         Dithane M-45   65.89        74.44
        75WP                            (64.38) *    (63.30)

2       Chlorothalonil   Kavach         58.52        68.33
        75% WP                          (55.77)      (66.85)

3       Captan 50%       Captaf         72.96        77.33
        WP                              (58.74)      (61.58)

4       Zineb 80 % WP    Dithane Z-78   37.48        61.67
                                        (51.75)      (37.75)

5       Control                         90.00        90.00
                                        (0.0)        (0.0)

Mean                                    71.06        69.79
                                        (57.66)      (37.75)

        (%) Inhibition over
              control          Mean
        Concentration (ppm)

S.      400        600
No

1       79.81      81.30      75.36
        (59.63)    (54.27)    (60.40)

2       81.11      84.52      73.12
        (64.28)    (49.93)    (59.21)

3       81.33      86.00      79.41
        (64.41)    (68.04)    (63.19)

4       70.81      75.33      61.32
        (57.35)    (60.22)    (51.77)

5       90.00      90.00      90.00
        (0.0)      (0.0)      (0.0)

Mean    76.93      71.44      72.30
        (61.42)    (58.11)    (58.64)

* Figures in parentheses are angular transformations

                    S.Em [+ or -]   CD @ 1 %

Fungicide (F)       0.51            1.99
Concentration (c)   0.51            1.99
F x C               1.02            3.98

Table 2(c). In-vitro evaluation of Combi-products fungicides
against C. nicotinae

                                          (%) Inhibition over
                                                 control
                                          Concentration (ppm)

S.      Fungicides            Trade       100         200
No                            name

1       Carbendazim-12% +     Companion   76.63       100.00
        Mancozeb-63%                      (61.09) *   (90.00)

2       Tebuconazole 50% +    Nativo G    91.04       100.00
        Trifloxystrobin 25%               (72.60)     (90.00)

3       Tricyclazole 4%       Avatar      71.80       74.15
        +Mancozeb 62 % WP                 (57.93)     (60.22)

4       Hexaconazole 4%       Merger      74.85       77.78
        +Zineb 68% WP                     (61.88)     (68.83)

5       Control                           90.00       90.00
                                          (0.0)       (0.0)

Mean                                      78.58       87.98
                                          (63.37)     (77.26)

        (%) Inhibition over
              control         Mean
        Concentration (ppm)

S.      400        600
No

1       100.00     100.00     94.16
        (90.00)    (90.00)    (82.77)

2       100.00     100.00     97.76
        (90.00)    (90.00)    (85.65)

3       75.33      90.00      77.82
        (59.44)    (71.57)    (62.29)

4       84.30      86.96      80.96
        (59.90)    (60.66)    (62.81)

5       90.00      90.00      90.00
        (0.0)      (0.0)      (0.0)

Mean    89.90      94.24      87.65
        (74.84)    (78.05)    (73.38)

* Figures in parentheses are angular transformations

                    S.Em [+ or -]   CD @ 1 %

Fungicide (F)       0.12            0.47
Concentration (c)   0.12            0.47
F x C               0.24            0.95

Table 3. Evaluation of different fungicides against C. nicotianae

S.    Treatments           Concentration    PDI     TGE *      C:B
No                              (%)                (Kg/ha)    ratio

T1    Hexaconazole 5 %          0.1        29.15     792      1:1.9
      EC. (Contaf)

T2    Propiconazole             0.1        31.75     696      1:2.0
      25 % EC. (Tilt)

T3    Carbendazim - 12 %        0.2        42.25     576      1:1.0
      + Mancozeb - 63%
      (Companion) WG

T4    Trifloxystrobin          0.05        36.25     452      1:1.0
      25 % and
      Tebuconazole
      50 %WG (Nativo)

T5    Mancozeb 75 % WP          0.2        32.86     666      1:1.2
      (Dithane M-45)

T6    Carbendazim 50 %          0.1        26.00    1186      1:3.2
      WP (Bavistin)

T7    Control                              67.25     210     1:-0.09

S.Em [+ or -] C.D. 5%                      2.08     3.11

                                           6.40     9.25

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Article Details
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Author:Kumar, N.D. Punit; Karegowda, C.; Murali, R.; Sayiprathap, B.R.; Mahesh, M.; Nagaraj, H.; Raju, J.;
Publication:Journal of Pure and Applied Microbiology
Article Type:Report
Geographic Code:9INDI
Date:Mar 1, 2016
Words:2473
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