Madras Agric. J. 92 (10-12) : 660 - 666 October-December - 2005

660

MANAGEMENT OF LEAF BLIGHT DISEASE IN SOLANUM NIGRUM BY FUNGICIDES AND NUTRIENTS S. VANITHA, D. ALICE and S. PANEERSELVAM Department of Plant Pathology, Tamil Nadu Agricultural University, Coimbatore - 641 003. Abstract : The experimental results of the study for the management of leaf blight disease in Solanum nigrum L. by nutrients and fungicides revealed that the fungicide Mancozeb 0.2 per cent recorded the complete inhibition of mycelial growth and spore germination.The nutrient 0.1 per cent spray recorded 18.25 per cent reduced mycelial growth and 24.33 per cent spore germination. In the pot culture and field experiments also minimum incidence in mancozeb and CaCl2 treated plot was observed along with higher yield in terms of leaf and berries.

INTRODUCTION

In vitro evaluation of fungicides on mycelial growth of A. chlamydospora under in vitro conditions

Black Nightshade (Tamil: Manathakkali) is the vernacular name of Solanum nigrum L. which belongs to the family Solanaceae. This herb is nowa-days gaining importance in pharmaceutical industry due to its amazing drug potential. The active principle in this herb is solasodine, a glucosidal alkaloid. Leaf blight of S. nigrum was noticed during 2001 in field as well as in home gardens in parts of Coimbatore district of Tamil Nadu. The pathogen was isolated, identified and confirmed by Agarkar Mycological Research Institute, Pune. The occurrence of this pathogen in S. nigrum is not reported so far and it is the new report. Considering the importance of the crop, destructive nature of the disease and availability of limited information on this pathogen in this crop, the present studies were undertaken for developing effective management strategies for Alternaria blight disease through nutrients and fungicides

Six fungicides viz., Mancozeb, Copper oxychloride, Thiophenate-Methyl.Hexaconazole, Carbendazim and Chlorothalonil were tested at recommended concentrations. Required quantity of each fungicide was added directly to 50 ml of sterilized PDA medium at 45°C so as to get desired concentration and mixed thoroughly with the medium. About 15 ml of the mixture was poured into sterilized Petri plates separately for each concentration. Each concentration was replicated thrice. PDA medium without fungicide served as control. Petri plate was inoculated with 10 mm culture disc taken from the periphery of five days old culture and incubated at room temperature (28 ± 2°C). When the control plate showed full growth of the pathogen, the diameter of the mycelial growth was measured and the results were expressed as per cent inhibition over control. Per cent inhibition of growth over control was calculated by following the equation given by Vincent (1927).

MATERIALS AND METHODS

Effect of fungicides on spore germination of A. chlamydospora under in vitro conditions

In vitro evaluation of Nutrients against the mycelial growth and spore germination of A. chlamydospora under in vitro conditions To find out whether nutrients have any direct antifungal activity over the pathogen, ten chemicals viz., KNO3, FeSO4, NaCl 2, CaCl 2, ZnSO4, MgCl2, MgSO 4, FeCl2, KCl and NaNO3 were assayed by poisoned food technique. The inhibitory effect of these chemicals on the mycelial growth and spore germination of A. chlamydospora was studied.

The spores of the fungus were harvested separately by flooding with sterile water and also crushing the mycelial mat using pestle and mortar and centrifuged at 5000 rpm for 10 min. The spore suspension was prepared with a concentration of 5 x 105 conidia m-1 using a haemocytometer. One drop of spore suspension was added to the fungicide in the cavity slides kept in a moist chamber and incubated at room temperature (28 ± 2°C). The spore suspension mixed with sterile distilled water served

MANAGEMENT OF LEAF BLIGHT DISEASE IN SOLANUM NIGRUM BY FUNGICIDES AND NUTRIENTS

as control. Three replications were maintained and the per cent spore germination was recorded after 24h. Effect of foliar application of crude plant extracts and oils against leaf blight disease under pot culture conditions Solarium nigrum plants were raised in mud pots (30 cm diameter) in glass house. The plants 25 days after planting were sprayed with spore suspension of A. chlamydospora (5 x 10 5 conidia/ ml). Two days after inoculation, the plants were sprayed with CaCb and Six fungicides viz., Mancozeb, Copper oxychloride, ThiophenateMethyl, Hexaconazole, Carbendazim and Chlorothalonil. A total of three sprayings were given at 15 days interval, one at 30 DAP and subsequent sprays at 15 days interval (45 DAP and 60 DAP). The incidence of the leaf spot was recorded after each spray. Three replications were maintained. The Per cent Disease Index (PDI) and economic yield were recorded. The per cent disease index was calculated by using Me Kinney (1923) formula. The results were expressed as per cent disease reduction over control. The yield data were recorded in terms of total economic yield (leaf and berries) per plant. Evaluation of nutrients and fungicides against leaf blight under field condition In order to study the effect of nutrients and fungicides under field condition, a trial was conducted in farmers field at Linganoor, Coimbatore. The local variety of S. nigrum was used for the study. The experiment was laid out in Randomized Block Design (RBD) with above cited eight treatments under three replications with the plot size of 4 x 3.5m 2. Totally 3 sprays were given, the first spray was given at 30 days after planting, second and third sprayings were given at 45 days and 60 days after planting. The observations on Per cent Disease Index and yield was recorded following the score chart of 0-9 scale. An economic yield (leaf and berries) data was recorded in terms of yield per plant. RESULTS AND DISCUSSION In vitro screening ofnutrients against mycelial growth and spore germination of A. chlamydospora

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The data given in Table 1 revealed that among the ten different nutrients evaluated under in vitro, calcium chloride (0.1%) recorded the mycelial growth of 18.25 mm and least spore germination (24.33%) followed by 0.1 per cent ZnSO4 which recorded 51.40 mm and 72.30 per cent respectively. The other chemicals were found less effective by recording maximum mycelial growth of the pathogen which ranged from 61.20 to 87.00 mm and 75.03 to 88.00 per cent spore germination as compared to control (mycelial growth of 87.00 mm and spore germination of 90.00 per cent.) In vitro screening of fungicides on mycelial growth and spore germination of A. chlamydospora The results given in Table 2 showed that all the fungicides were significantly superior in reducing the radial growth of the pathogen. Of these, Mancozeb at 0.2 per cent completely 100%) inhibited the mycelial growth and spore germination (100%) of A. chlamydospora followed by Thiophenate-Methyl which showed the mycelial growth of 26.70 mm and 21.30 per cent spore germination. This fungicide was on par with Copper oxychloride by recording 28.00 mm and 21.00 per cent respectively. Carbendazim was less effective by recording 71.10 mm and 81.07 per cent respectively. However, the control recorded the mycelial growth of 81.40 mm and 88.70 per cent spore germination. Effect of foliar application of nutrients and fungicides against leaf blight caused by A. chlamydospora under pot culture conditions The results given in Table 3 showed that the foliar application of Mancozeb (0.2%) thrice starting from 30 days after planting with an interval of 15 days was significantly superior over all the treatments with PDI of 26.28 on 60 days after planting. Thiophenate-Methyl was next best which recorded the PDI of 26.40 followed by Copper oxychloride (29.25 PDI). In this study, the per cent disease index recorded on 60 days after planting was found to be maximum in all treatments. However in control, the PDI was 59.06. The data related to economic yield was given in Table 3 which showed that there was a relationship between severity of the disease and loss of economic yield. As the disease severity

662 increased, the loss in yield was also increased. The loss in terms of total dry weight ranged from 26.32 to 59.02 g plant -1. Mancozeb (0.2%) recorded significantly the highest yield of 59.02 g plant-1 followed by CaCl 2 and Thiophenate-Methyl (53.14 and 52.60g plant-1). The untreated control recorded the yield of 2632 g plant-1. Effect of foliar application of nutrients and fungicides against leaf blight caused by A. chlamydospora under field conditions The results of field trail showed that the fungicide Mancozeb recorded 7.18 per cent disease incidence of leaf blight and the nutrient CaCk recorded 7.23 per cent disease incidence of leaf blight. This was followed by Thiophenate- Methyl which recorded the disease of 9.51 per cent. The data related to economic yield interms of total dry weight ranged from 26.32 to 75.00g plant-1. The highest yield was recorded in CaCl2 (0.2%) (75.00 g plant -1) followed by Mancozeb and ThiophenateMethyl (71.30 and 70.00 g plant-1). The untreated control recorded the yield 40.00g plant-1 (Table 4). Castaneda and Perez (1996) showed that calcium chloride suppressed the growth of A. alternata in citrus. Narasimhan et al. (1995) stated that soil application of CaSO4 in the form of gypsum also reduced the incidence of sheath blight in rice. Veerasamy (1997) reported that CaCl 2 (0.1%) significantly reduced the leaf blight disease (incidence and intensity) caused by A. solani and A. alternata in brinjal. Vijayasamundeeswari (1999) reported that CaCl2 at 0.1 per cent was effective against A. alternata causing leaf blight in chilli. These results are in agreement with the findings of Gupta (1986) who reported that Dithane M- 45 was effective against A. solani in tomato. Wadibhasme et al. (1994) reported that Mancozeb at 0.2 per cent showed the highest inhibition of mycelial growth of A. helianthi. Mukesh et al. (2000) reported that Mancozeb was effective at higher concentration against A. alternata affecting onion. Mazumdar (2000) reported that Indofil M-45 (Mancozeb 0.2%) was significantly superior over other fungicides against A. dianthi causing leaf blight in marigold Dubey et al. (2000) reported that the three sprays of Topsin M (0.1%) showed the best control of the disease in field conditions resulting in maximum yield followed by Topsin M (0.05 %) + Indofil M-45

S. VANITHA, D. ALICE and S. PANEERSELVAM

(0.1 %). Thomas (1983) observed that Dithane M45 was the most effective against the leaf blight of cantaloupe caused by A. cucumerina. Amaresh et al. (2000) reported that Mancozeb (0.2%) was effective in inhibiting the mycelial growth of A. alternata. Vishwakarma and Pandey (1995) reported that Mancozeb (0.2%) sprayed at 10 days interval was superior which reduced Alternaria blight incidence of brinjal. Archana Katiyar et al. (2001) reported the best control of leaf spot of bottle gourd caused by A. cucumerina was obtained by the application of 0.2 per cent Indofil M-45. Chattopadhyay (1989) reported that application of Dithane M-45 recorded maximum yield against early blight of potato. Alasgarcia and Bustamante (1993) stated that the disease resistance against A. solani was increased when treated with different combination of limestone (0.1 and 4 tonnes/ha). Calcium nitrate used as soil application (2.4 g / plot) and also as foliar spary (16 g/1 ) reduced the lesion length of A. solani in tomato (Mendez et al, 1994). Castaneda and Perez (1996) stated that resistance against A. alternata was induced by Calcium chloride (0.1%) application by increasing the phenylalanine ammonia lyase activity. REFERENCES Alasgaricia, J. and Bustamante, E. (1993). The effect of phosphorus and calcium on the severity of early blight (A. solani) on tomato in the green house. Manejo Integrado de Plagas, 29: 1-5. Amaresh, Y.S., Nargund, V.B. and Somasekhar, B. (2000). Use of botanicals and fungitoxicants against Alternaria helianthi, the causal agent of sunflower leaf blight. Pl. Dis. Res., AS(2): 140-145. Archana Katiyar, Sandhya Kant, Chauhan, S.S. and Alka, S. (2001). Chemical control of Alternaria leaf spot of bottle gourd. Ann. Pl. Prot. Sci., 9 : 339 -341. Castaneda, P. and Perez, L.M. (1996). Calcium ions promote the response of citrus limon against fungal elicitors or wounding. Phyto chemistry, 42:595-598.

MANAGEMENT OF LEAF BLIGHT DISEASE IN SOLANUM NIGRUM BY FUNGICIDES AND NUTRIENTS

Chattopadhyay, C. (2001). Yield loss attributable to Alternaria blight of sunflower (Helianthus annus L.) in India potentially an effective control measure. J. Pest Management, 45: 1521. Dubey, S.C., Patel, B. and Jha. D.K. (2000). Chemical management of Alternaria blight of broad bean. Indian Phytopath., 53(2): 213 - 215. Gupta, U. (1986). Chemical control of early blight of potato. Indian Phytopath., 39: 153. (Abstr.). Mazumdar, N. (2000). Epidemiological factors in relation to development of Alternaria leaf blight of Marigold and fungicidal control. Pl. Dis. Res., 15: 28 - 33. McKinney, H.H. (1923). A new system of grading plant disease. J. Agric. Res., 26: 195-218.

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Thomas, C.E. (1983). Fungicide application based on duration of wetness period to control Alternaria leaf blight of cantaloupe in South Texas. Pl. Dis., 67: 145-147. Veerasamy, S. (1997). Studies on management of leaf blight disease of brinjal (Solanum melongena) caused by Alternaria solani (EII. And Mont.) Jones and Grout, Ph.D. Thesis, Tamil Nadu Agricultural University, Coimbatore, India. 126 p. Vijayasamundeeswari, A. (1999). Studies on the management of chilli leaf blight caused by Alternaria alternata (FR) Keissler using botanicals (plant sp and resistance inducing chemicals). M.Sc. (Ag.) Thesis, Tamil Nadu Agricultural University, India. 99 p.

Mukesh, J, Patel, K.R., Joshi, K. and Vala, D.G. (2000). Cause of onion leaf blight in south Gujarat and screening of botanicals. Indian J. Mycol. Pl. Pathol., 30: 128.

Vincent, J.M. (1927). Distortion of fungal hyphae in the presence of certain inhibitors. Nature, 159: 850 p.

Narasimhan, V., Vijayan, M. and Senthilnathan, V. (1995). Efficiency of botanicals for the management of blight disease of two vegetable crops. In: Neem for the management of crop diseases (Ed. Dr.V. Mariappan) Associated Publishing Co., New Delhi, pp. 67-74 .

Vishwakarma, S.N. and Pandey, K.K. (1995). Chemical control of leaf spot of brinjal caused by Alternaria alternata inciting leaf blight of sunflower. J. Mycol. Pl. PathoL, 25: 110 p.

Sritharan, R. (2003). Physiological manipulation through bioregulators for the yield and quality improvement of Solarium nigrum L. M.Sc. (Ag.) Thesis, Tamil Nadu Agricultural University, Coimbatore, India 10 p.

Wadibhasme, S.S., Ingole, D.V. and Fuzele, G.R. (1994). Evaluation of fungicides in vitro against Alternaria helianthi inciting leaf blight of sunflower. J. Marathwada Agric. Univ., 19: 361 - 362.

664 Table 1. Sl.No

S. VANITHA, D. ALICE and S. PANEERSELVAM

In vitro screening of Nutrients (0.1%) on mycelial growth and spore germination of A. chlamydospora Treatments

*Mean mycelial growth (mm)

Per cent reduction over control

*Mean Spore germination (%)

Per cent reduction over control

1.

KNO3

86.80f (68.70)#

0.23

87.70cd (69.50)

2.56

2.

FeSO4

84.80e (66.46)

2.53

86.70cd (68.63)

3.67

3.

NaCl2

e

83.10 (65.74) a

4.50

c

7.00

a

84.00 (66.44)

4.

CaCl2

18.25 (25.30)

79.02

24.33 (29.50)

73.00

5.

ZnSO4

51.40b (45.80)

41.00

72.30b (58.23)

19.70

6.

MgCl2

86.95f (68.90)

0.60

88.00cd (69.80)

2 22

7.

MgSO4

f

87.00 (68.90) cd

0.00

cd

4.44

b

86.00 68.13)

8.

FeCl2

63.23 (52.70)

27.32

75.33 (60.22)

16.30

9.

KC1

66.25d (51.50)

23.90

75.03b (60.03)

16.63

10.

NaNO3

61.20c (51.50)

29.66

85.70c (67.80)

4.80

11.

Control

f

87.00 (68.90)

-

d

90.00 (71.60)

-

*Mean of three replications #Figures in parenthesis are arcsine-transformed values. In a column, means followed by a common letter (s) are not significantly different at 5 per cent level by DMRT.

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MANAGEMENT OF LEAF BLIGHT DISEASE IN SOLANUM NIGRUM BY FUNGICIDES AND NUTRIENTS

Table 2.

In vitro screening of different fungicides on mycelial growth and spore germination of A.chlamydospora

Sl. No. Treatments

*Mean mycelial growth (mm)

Per cent reduction over control

* Mean Spore germination (%)

Per cent reduction over control

1.

Mancozeb (0.2%)

0.03a (0.191)#

100.00

0.03a (0.191)

100.00

2.

Carbendazim(0.1%)

71.10* (57.50)

12.65

81.07e (64.00)

8.61

3.

Copper oxychloride (0.2%)

28.00c (32.00)

65.51

21.00b (27.49)5

76.33

4.

Hexaconazole (0.1%)

42.50d (40.70)

47.80

0.40° (45.20)

43.20

5.

Chlorothalanil (0.1%)

41.10d (39.90)

50.00

64.00d (53.04)

27.85

6.

Thiophanate-methyl (0.1%)

26.70b (31.10)

67.20

21.30b (27.44)

75.99

7.

Control

81.40f

--

88.70f (70.44)

--

* Mean of three replications # Figures in parenthesis are arcsine-transformed values. In a column, means followed by a common letter(s) are not significantly different at 5 per cent level by DMRT. Table3.

Effect of foliar application of nutrient and fungicides against leaf blight disease and yield of S. nigrum

Sl. Treatments No. 1. 2. 3. 4. 5. 6. 7. 8.

Mancozeb (0.2%) Carbendazim (0.1 %) Copper oxychloride (0.2%) Hexaconazole (0.1 %) Chlorothalanil(0.1%) Thiophenate-Methyl (0.1%) CaCl2(0.1%) Control

*Mean PDI wt (g)

*Leaf fresh

26.28a (30.90) 36.64C (37.30) 29.25b (32.80) 35.06° (36.31) 45.05e (42.15) 26.403 (30.90) 36.25d (37.02) 59.06f (50.22)

50.25a 18.63s 42.14b 40.83c 39.65d 34.94e 40.15° 20.15f

*Leaf dry *Fruit wt(g) fresh wt(g) wt(g) 18.43b 7.22g 20.143 21.123 16.82d 12.40e 18.14° 8.14f

190.42a 76.52f 120.74e 98.10d 90.81b 130.08b 110.00c 41.90*

Fruit dry (g/plant)

Total dry matter

40.59a 22.03° 36.00b 18.00d 19.0e 40.20a 35.00° 18.18f

59.02 29.25 56.14 39.12 35.82 52.60 53.14 26.32

* Mean of three replications # Figures in parenthesis are arcsine-transformed value. In a column, means followed by a common letter(s)are not significantly different at 5 per cent level by DMRT.

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S. VANITHA, D. ALICE and S. PANEERSELVAM

Table 4.

Effect of foliar application of nutrients and fungicides on the disease and yield of of S. nigrum under field conditions

Sl. Treatments No. 1. 2. 3. 4. 5. 6. 7. 8.

Mancozeb (0.2%) Carbendazim (0.1 %) Copper oxychloride (0.2%) Hexaconazole (0.1 %) Chlorothalanil(0.1%) Thiophenate-Methyl (0.1%) CaCl2(0.1%) Control

*Mean PDI wt (g)

*Leaf fresh

26.28 (30.90) 36.64C (37.30) 29.25b (32.80) 35.06° (36.31) 45.05e (42.15) 26.403 (30.90) 36.25d (37.02) 59.06f (50.22)

130.23b 70.79' 64.75de 45.84e 73.24d 170.423 170.24' 50.00f

*Leaf dry *Fruit wt(g) fresh wt(g) wt(g) 33.87b 21.78e 24.42de 28.20' 25.52cd 31.97h 35.43' 20.00f

148.22b 77.80d 70.40' 54.60' 3.86' 153.40b 180.60' 55.00f

Fruit dry (g/plant)

Total dry matter

37.41° 22.42e 23.04' 24.30d 21.80g 38.80" 40.06' 20.00f

71.30 44.20 47.46 52.50 47.32 70.80 75.00 40.00

* Mean of three replications # Figures in parenthesis are arcsine-transformed value. In a column, means followed by a common letter(s)are not significantly different at 5 per cent level by DMRT.