Indian Phytopath. 63 (3) : 345-347 (2010)

Prevalence of canker in kinnow ( deliciosa Ten.) and its management

R.B. GAUR* and R.N. SHARMA Department of Plant Pathology, Agricultural Research Station (Rajasthan Agricultural University), Sriganganagar 335 001

Key words: Kinnow, canker, antibiotics, fungicides, bioagents, botanicals

Kinnow (Citrus deliciosa Ten.) is a hybrid variety of S All numerical ratings mandarin group of citrus and was selected from the cross PDI = —————————————————————————–x 100 between King (Citrus nobilis Lour) x Willow leaf Total no. of leaves assessed x Maximum disease rating mandarin (C. deliciosa Ten.). Mandarins occupy a prominent position and account for over 50% of the total citrus areas Controlling of kinnow through chemicals (1). In , citrus accounts for about nine per cent of the and biorational spray total fruit production (2). Canker is one of the most threatening A field trial for controlling citrus canker of kinnow was carried diseases of citrus which attacks all the aerial parts and out on ten years old kinnow plants grown in orchards at adversely affects the quality as well as quantity of fruit yield Agricultural Research Station (Rajasthan Agricultural resulting in severe economic loss. It is difficult to find any University), Sriganganagar for three consecutive years from grove completely free from canker and infection can 2003-04 to 2005-06. The plants having uniform disease cause 50-60% yield reduction (4). The disease is incidence were selected for the experiment. The plants were characterized by the conspicuous necrotic lesions on sprayed with chemicals like streptocycline (90% leaves, fruits and twigs (Fig. 1a, b and c). Severe infection Streptomycin sulphate + 10% Tetracycline hydrochloride) cause defoliation, die-back and premature fruit drop. The @ 100 ppm, carbendazim @ 0.1% (Bavistin 50% WP), disease is caused by Xanthomonas axonopodis pv. citri (15). In Rajasthan, this disease was first observed during 2002 year in kinnow orchards situated in Sriganganagar district. Though the disease can be checked by chemicals like copper oxychloride and streptocycline (8, 10, 13) but because of high cost, risk of resistance development in pathogen and harmful effect on environment, limits their use. Therefore, efforts were made to explore the possibilities (a) of biorational approach to control this disease and provide a cheaper and eco- friendly management strategy for the disease.

Survey of kinnow orchards

In order to find out the prevalence of citrus canker of kinnow at cultivator’s field, ten orchards at different locations of Sriganganagar (Layalpur farm, 5 Z, Vishnu Garden, Chak 2 (b) E Choti, Khanuja farm, 10-Z, Agricultural Research Station) and Srikaranpur (11-FF, 19-Q, 11-FF) tehsils of Rajasthan and adjacent Abohar tehsil (Khubban, Sappanwali, Gidrawali) of were selected. Ten plants from each orchard having 10-15 years old plants were randomly surveyed during 2003-04 to 2005-06. Forty leaves were randomly selected from each plant for the observation of canker. The disease incidence was scored using 0-4 scale (Fig. 1a), where 0= free from infection, 1= traces to 10%, 2= 11-25%, 3= 26-50% and 4= >50% leaf area infected (7, 12). Per cent disease index (PDI) was calculated as follows. (c) Fig. 1. Citrus canker (X. axonopodis pv. citri) of Kinnow (C. deliciosa) *Corresponding author: [email protected]; (a) Leaves showing different ratings of disease (0-4 scale); (b) [email protected] Canker lesions on twigs; (c) Canker lesions on fruits 346 Indian Phytopathology [Vol. 63(3) : 2010]

Table 1. Prevalence of canker in kinnow (C. deliciosa Ten.) at different cultivator’s fields S. Location % Disease intensity Mean No. 2003-04 2004-05 2005-06 1 Layalpur farm, 5 Z, Sriganganagar (Rajasthan) 63.8 50.6 71.3 61.9 2 Vishnu Garden, Chak 2 E Choti, Sriganganagar (Rajasthan) 42.5 68.1 59.4 56.7 3 Khanuja farm, 10-Z, Sriganganagar (Rajasthan) 43.1 40.6 46.9 43.6 4 Agricultural Research Station, Sriganganagar (Rajasthan) 37.5 32.5 35.6 35.2 5 11-FF, Srikaranpur (Rajasthan) 59.4 63.8 71.3 64.8 6 19-Q, Srikaranpur (Rajasthan) 39.4 45.6 48.1 44.4 7 26-H, Srikaranpur (Rajasthan) 35.6 48.1 39.4 41.1 8 Khubban, Abohar (Punjab) 66.9 79.4 83.8 76.7 9 Sappanwali, Abohar (Punjab) 68.1 74.4 75.6 72.7 10 Gidrawali, Abohar (Punjab) 64.4 71.3 68.1 67.9 Mean 52.1 57.4 59.9 56.5

Table 2. Efficacy of chemicals and biorationals spray schedules against the canker of kinnow Treatments % Disease index Pooled % Disease 2003-04 2004-05 2005-06 control Streptocyclene @ 100 ppm 52.0 (46.1) 35.0 (36.3) 27.7 (31.7) 38.2 (38.0) 44.5 Streptocyclene @ 100 ppm + carbendazim @ 0.1% 40.3 (39.4) 25.0 (30.0) 22.7 (28.4) 29.3 (32.0) 57.4 Streptocyclene @ 100 ppm + copper oxychloride @ 0.2% 32.1 (34.5) 20.2 (26.6) 17.6 (24.8) 23.3 (28.6) 66.1 Streptocyclene @ 100 ppm + DC Tron plus @ 0.5% 47.0 (43.3) 30.2 (33.3) 27.8 (31.8) 35.0 (36.1) 49.1 Streptocyclene @ 100 ppm + Aureofungin @ 25 ppm 50.6 (45.4) 30.2 (33.3) 27.8 (31.8) 36.2 (36.8) 47.4 Talc based Pseudomonas fluorescens (1 x 109 ) @ 0.2% 37.5 (37.7) 20.8 (27.1) 21.9 (27.9) 26.8 (30.9) 61.1 Garlic @ 2.5 g/L water + green chilli extract @ 250 mg/L water 54.9 (47.8) 36.5 (37.2) 35.7 (36.7) 42.4 (40.6) 38.5 Fresh cow urine @ 100 ml/L water 55.1 (47.9) 43.3 (41.2) 32.2 (34.6) 43.6 (41.2) 36.7 DC Tron plus @ 0.5% 61.6 (51.7) 47.3 (43.5) 37.7 (37.9) 48.9 (44.4) 29.0 Copper oxychloride @ 0.3% 60.6 (51.1) 47.3 (43.5) 42.3 (40.6) 50.1 (45.1) 27.2 Control 87.0 (68.9) 72.5 (58.4) 47.0 (43.3) 68.8 (56.9) - C D at 5 % 3.3 1.5 3.0 1.7 C V (%) 4.2 4.9 5.1 4.7 - Figures in parenthesis are angular transformed values. copper oxychloride @ 0.2 and 0.3% (Blitox 50% WP), DC- The orchards at Abohar tehsil in Punjab were highly infected Tron plus @ 0.5% and Aureofungin @ 25 ppm (Aureofungin with canker showing disease intensity between 67.9 - 76.7 46.15% SP) and biorationals like talc based Pseudomonas per cent (Table 1). Though disease intensity ranging fluorescens (1 X 109 cfu/g) @ 0.2%, fresh cow urine @ 100 between 26 to 39% has been reported by earlier workers ml/L of water, garlic @ 0.25% and green chilli extract @ 250 (3, 9) but information generated under present study ppm, separately or in association during the month of accounts new for kinnow growing belt. February and August, twice in each month at 15 days intervals. The plants sprayed with only water served as Effect of foliar sprays control. The experiment was conducted in completely randomized block design with three replications Three years data of disease intensity in kinnow showed considering a single plant as one replication. The that all the chemicals and biorationals reduced the disease observations on disease grade were recorded after one to varying degree. Foliar spray of streptocycline @ 100 ppm month of last spray in each month (February and August) in association with copper oxychloride @ 0.2% proved and the percent disease index (PDI) was calculated. significantly superior to rest of sprays in controlling citrus canker. The spray of talc based P. fluorescens @ 0.2% was Prevalence of canker in kinnow orchards found next in order of efficacy against the disease. The spray of streptocycline @ 100 ppm in association with The yearly average intensity of canker in different tehsils of carbendazim @ 0.1% also reduced the disease (Table 2). Rajasthan and Punjab ranged between 35.6 to 68.1 (2003- Foliar spray of garlic + green chili extract reduced 38.5% 04), 32.5 to 79.4 (2004-05) and 35.6 to 83.8% (2005-06). disease, differing insignificantly with fresh cow urine spray. The overall disease intensity in Sriganganagar tehsil Copper oxychloride @ 0.3% proved least effective in ranged between 35.2 to 61.9%, lowest being at Agricultural controlling canker. The possible reasons for not getting Research Station. In Srikaranpur tehsil of the Rajasthan, complete control of disease could be (a) lack of coverage the disease intensity ranged between 41.1 to 64.8 per cent. of canker lesions by spray solution because of thick plant [Vol. 63(3) : 2010] Indian Phytopathology 347 canopy (b) failure of chemicals or biorationals to penetrate 2. Chadha, K.L. (1995). J. Applied Hort. 1: 1-18. through thick corky and mecrotic lesions. 3. Das, A.K. and Singh, S. (1999). Proc. Intr. Symp. Citriculture, held at NRC for Citrus, Nagpur (Nov. 23-27). Although complete elimination of the bacterial pathogen was not possible in the present investigation, it 4. Das, A.K. (2001). Bacterial diseases of citrus and their management. In: Citrus. (ed. Shyam Singh and S.A.M.H. appeared that foliar sprays of chemicals (streptocycline + Naqvi). IBDC, Publishers, Lucknow(U.P.), pp. 395-406. copper oxychloride) or bioagent (P. fluorescens) can reduce 5. Defago, G. (1993). 2, 4- Diacetylphloroglucinol, a promising the canker incidence in kinnow considerably. Thind et al. compound in biocontrol. Plant Pathol. 42: 311-312. (14) also reported that copper oxychloride + streptocycline significantly reduced the canker incidence and premature 6. Jadeja, K.B., Mayani, N.G., Patel, V.A. and Ghodasara, M.T. (2000). J. Mycol. Pl. Pathol. 30: 87-88. leaf shedding in kinnow mandarin. The use of streptocycline and copper oxychloride against the citrus canker has also 7. Kale, K.B., Kolte, S.O. and Peshney, N.L. (1994). Indian Phytopath. 47: 253-255. been suggested by some other workers (6, 7, 11). The efficacy of P. fluorescens against the canker disease may 8. Kale, K.B. and Peshney, N.L. (1997). Proc. Nat. Symp. be attributed to the antibiosis against the pathogen through Citriculture, held at NRC for Citrus, Nagpur (Nov. 17-19), pp. 486. the production of antibiotics like “2, 4-diacetylphloroglucinol” which have broad spectrum activity against a range of plant 9. Kapur, S., Cheema, S.S. and Kapur, S.P. (1997). Pl. Dis. Res. 12: 159-161. pathogens (5). 10. Krishna, A. and Nema, K.G. (1983). Indian Phytopath. 36: The spray of talc based P. fluorescens (1 X 109 cfu/g) @ 348-350. 0.2% during the month of February and August, twice in 11. Raijadhav, S.B., Bulbule, S.V. and Shinde, M.M. (1999). each month at 15 days intervals is suggested for eco-friendly Proc. Intr. Symp. Citriculture, held at NRC for Citrus, Nagpur management of the canker disease in kinnow. (Nov. 23-27). 12. Reddy, M.R.S. (1997). J. Mycol. Pl. Pathol. 27: 80-81. ACKNOWLEDGEMENT 13. Singh, R. (1994). Studies on bacterial diseases of fruit crops. Ann. Report IIHR, Bangalore. 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