Die Bekämpfung der durch Aspergillus niger und Botryodiplodia theobromae an geernteten Trauben verursachten FäulnisTrauben der Sorten Thompson Seedless, Anab-e-Shahi und Kishmish wurden nach der Ernte mit A. niger und B. theobromae - sowohl rein als auch gemischt - infiziert. Die Wirksamkeit verschiedener Nahrungskonservierungsmittel, Pflanzenöle, Wachstumsregulatoren, homoeopathischer Drogen, Antibiotika und Fungizide, vor und nach der Inokulation angewandt, wurde gepriift. Durch die Behandlung der geernteten Trauben mit Bavistin (0,1 % ) + Kaliummetabisulfit (5 % ) könnten hohe wirtschaftliche Verluste vermieden werden

Dasgupta, M. K.

Mandal, N. C.

English

JKI Open Journal Systems (Julius Kühn-Institut)

Vitis 23, 202-204 (1984) Plant Pathology Laboratory, Palli Siksha Sadana (College of Agriculture), Visva-Bharati, Sriniketan, Birbhum, West Bengal, lndia Control of postharvest grape rots caused by Aspergillus niger and Botryodiplodia theobromae 1) by N. c. MANDAL and M. K. DASGUPI'A Die Bekämpfung der durch Aspergillus nigerund Botryodiplodia theobromae an geernteten Trauben verursachten Fäulnis Zu s a m m e n f a s s u n g . - Trauben der Sorten Thompson Seedless, Anab-e-Shahi und Kishmish wurden nach der Ernte mit A. niger und B. theobromae - sowohl rein als auch gemischt - infiziert. Die Wirksamkeit verschiedener Nahrungskonservierungsmittel, Pflanzenöle, Wachs-tumsregulatoren, homoeopathischer Drogen, Antibiotika und Fungizide, vor und nach der Inokula-tion angewandt, wurde gepriift. Durch die Behandlung der geernteten Trauben mit Bavistin (0,1 % ) + Kaliummetabisulfit (5 % ) könnten hohe wirtschaftliche Verluste vermieden werden. Postharvest losses of grapes were found to vary between 4 and 60 % (MANDAL and DASGUPl'A 1981 ). Among the pathogens occurring on grape, Aspergillus niger V AN TIEGH. and Botryodiplodia theobromae PAT. caused 5---30 % and 0-25 % loss, respectively, in West Bengal (India) (MANDAL, 1981). The synergistic nature of association in their mixed inoculation has been discovered (MANDAL and DASGUPI'A 19B2 a). Control of post-harvest diseases of grapes has recently been reviewed (MANDAL and DASGUPl'A 1982 b), which reveals that no attempt has been made to control B. theobromae or mixed infec-tion of A. niger and B. theobromae. In this communication, results of the attempts to control A. niger and B. theobromae either singly or in combination have been reported. Apparently uninfected grape fruits (cvs. Thompson Seedless, Anab-e-Shahi and Kishmish) were surface-sterilized (dipping in 0.1 % HgC12 for 30 s followed by several washings in sterile water), inoculated by dipping for 5 min in conidial suspensions (50 x 103 spores/ml) and blended mycelial mass of A. niger and B. theobromae, respec-tively. An interval of 24 h was maintained between treatment (dipping for 5 min) and inoculation or vice versa for pre- and postinoculation treatments, ·respectively. After 10 d of incubation at room temperature (32 ± 4 °C), effects of the treatments were observed and analysed by using the variables such as per cent infection, degree of sof-tening (0-3 point scale), superficial growth and/or sporulation (0-3 point scale), aver-age infection index (0-5 point scale), change in colour, flavour, residue left etc. (MAN-DAL 1981). The chemicals used at different doses were food preservatives, vegetabl~ oils (linseed oil, chalmugra oil, neem oil), growth regulators (2,4-D, MH, GA, cycocel [(2-chloroethyl) trimethyl ammonium chloride]), homeopathic drugs (Blatta orientalis, Ca-lotropis, Gina, Filix mas, Ruta graveolens, Tercium), antibiotics and fungicides ( chemi-cal names provided in MERCER 1979). In the preinoculation treatment against A. niger, none of the 14 treatments was effective. In the postinoculation treatment against A. niger out of 12 treatments only bavistin (0.05 % for 5 min) was found to be effective (87 % reduction in infection) and since it has no known or observed undesirable effect, it deserves strong recommenda-') Part of the Ph. D. Thesis of N. C. MANDAL approved by Visva-Bharati, Santiniketan, India. Control of postharvest grape rots by A. niger and B. theobromae 203 tion. This confirms the findings of TANDON et al. (1977) (cit. MANDAL and DASGUPI'A 1982 b). lt is interesting that benomyl was not effective which suggested further inves-tigation (MARsH 1977). Preinoculation treatments against B. theobromae were carried out with 24 treat-ments, but only potassium metabisulphite (5 % ) was most effective, although with a tendency to slight desiccation. Diphenylamine (0.1 % of both aqueous and alcoholic) and macuprax (0.2 % ) were effective, but caused discolouration and left undesirable residues, respectively. However, although effectiveness of S02 fumigation was reported (NELSON and AHMEDUALLA 1972), dipping in sodium metabisulphite was not found to be effective against Botrytis cinerea, when treated after 6 h of inculation (COMBRINA 1975, cit. MANDAL and DASGUPI'A 1982 b ). In the postinoculation treatment against B. theobromae, TBZ (0.25 %), bavistin (0.05 %), benomyl (0.1 %), topsin M-70, (0.1 %), NF-48 (0.01 %) were effective, but con-sidered undesirable in one or more respects. Aureofungin (0.1 %}, griseofulvin (125 ppm), nystatin (0.2 %), calixin (0.1 %), bot water treatment (52 °C for 5 min) were not effective. For control of spoilage against the mixed inoculation of A. niger and B. theobro-mae at the postinoculation stage, out of 21 treatments, bavistin (0.1 % ) + potassium metabisulphite (5 % ) were highly effective (80 % reduction) and could be recom-mended. NF-48 (0.1 %) + potassium metabisulphite (5 %) were highly effective; NF-48, however, has been claimed tobe carcinogenic. Rest of the treatments were either not effective or effective, but left one or more undesirable effects. Storage of surface-sterilized apparently uninfected grapes in refrigerator (3-5.5 °C) followed by room temperature (28.3-36.1 °C and 61.2-68.4 % RH) indicated that grapes could be cold-stored at least up to 35 d and shelved for another 10 d at room temperature. While it is generally recommended to store grapes at 0.2 °C (PORRI'IT 1974), our results indicated that higher temperatures may not be harmful. This piece of information may be useful for shipping of grapes and to the homemakers. Assuming 25 % average loss, annual loss was computed to be 90,000 t and Rupees 800 millions ($ 100 millions) in lndia. The case of mixed treatment of bavistin (0.1 %) +potassium metabisulphite (5 %) has been computed at the rate of Rs. 100/t ($ 12.5) and 20 % average loss can be saved that way. Authors are thankful to Visva-Bharati for providing laboratory facilities. N. C. MANDAL acknowledges the financial support received from the Council of Scientific and Industrial Research, New Delhi. References MANDAL, N. C., 1981: Post-harvest diseases of fruits and vegetables in West Bengal. Ph. D. Thesis, Visva-Bharati. - - and DASGUPrA, M. K., 1981: Post-harvest diseases of perishables in West Bengal. II. Losses. Ann. Agricult. Res. 2, 73--85. - - and - -, 1982 a: Post-harvest diseases of persihables in West Bengal, India. Indian Phyto-pathology 35, 645--649. - - and- -, 1982 b : Control of post-harvest diseases of fruits. Pesticides Information 8 (2), 6---16. MARSH, R. W., 1977: Systemic fungicides. 2nd Ed. Longman, London. MERCER, S . L., 1979: Pans pesticide index - 1979 edition. Centre for Overseas Pest Research, Lon-don. 204 N. c. MANDAL and M. K. DASGUPI'A NELSON, K. E. and AHMEDUALLAH, M., 1972: Effect of type of inpackage S02 generator and packaging material on quality of stored table grapes. Amer. J . Enol. Viticult. 23, 290-301. PoRRI'IT, S. W., 1974: Commercial storage of fruit and vegetables. Information Division, Canada Department of Agriculture, Ottawa. Eingegangen am 14. 2. 1984 Dr. N. C. MANDAL Lecturer in Plant Pathology Dr. M. K. DASGUPrA Reader in Plant Pathology Plant Pathology Laboratory Palli Siksha Sadana (College of Agriculture) Visva-Bharati Sriniketan 731236 Birbhum, West Bengal India 

Control of postharvest grape rots caused by Aspergillus niger and Botryodiplodia theobromae

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Control of postharvest grape rots caused by Aspergillus niger and Botryodiplodia theobromae

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